# Pathology Grand Rounds: April 6, 2023 - Abner Louissaint, MD, PhD

April 06, 2023## Information

Translating Molecular Characterization and Preclinical iInvestigation of B-cell Lmphomas into Impactful Therapeutic Opportunities - by Abner Louissaint, MD, PhD

ID9812

To CiteDCA Citation Guide

- 00:00All right. It is my great pleasure
- 00:03to introduce Doctor Abner Lucent
- 00:06for our grand rounds today.
- 00:08Doctor Lucent is a hematopathologist
- 00:10at MGH and associate professor
- 00:12at Harvard Medical School.
- 00:14Upon graduating from college at Wash U,
- 00:16he went to Cornell for his MDPHD,
- 00:18followed by a PCP residency and
- 00:21then Heme Path Fellowship at MGH.
- 00:24He has since been there,
- 00:24rising to the rank of associate professor.
- 00:26He is currently director
- 00:28of the Hematology Lab.
- 00:30As well as the nascent
- 00:33lymphoma tissue repository, Dr.
- 00:35Luson has characterized novel
- 00:37subtypes of follicular lymphoma
- 00:39such as pediatric type follicular
- 00:41lymphoma and has defined the genetic
- 00:44underpinnings of these tumors.
- 00:45So specifically,
- 00:46his initial study in blood
- 00:48demonstrated the genomic differences
- 00:50between pediatric type and the
- 00:53traditional follicular lymphoma,
- 00:54representing a major advancement
- 00:56in the field.
- 00:57On the basis of this work
- 00:59and also follow up studies.
- 01:00PD type molecular lymphoma is
- 01:02now a distinct entity in The Who.
- 01:04More recently,
- 01:05he has characterized the genetic
- 01:07landscape of additional lymphoma
- 01:09subtypes including primary
- 01:10duodenal follicular lymphoma,
- 01:12primary cutaneous follicle
- 01:13center cell lymphoma,
- 01:15primary cutaneous gamma delta T
- 01:16cell lymphoma, as well as DLBCL.
- 01:19Leg type Doctor Lusan's lab has
- 01:21established the first ever PDX
- 01:23model of follicular lymphoma.
- 01:25He is currently an author for
- 01:27five chapters of the upcoming
- 01:285th edition of The Who and lead
- 01:31author for four of these chapters.
- 01:33He's highly involved in ash,
- 01:35working on the Publications committee as
- 01:37well as the Abstract Review Committee.
- 01:39He has won the Benjamin Councilman Award,
- 01:41outstanding paper and pathology
- 01:43through use CAP,
- 01:44as well as the Berard Dorfman Founders
- 01:46Award for Young investigators
- 01:48through Society for HEMATOPATHOLOGY.
- 01:51I knew of Abner,
- 01:52but then got to know him personally
- 01:54through a rather epic study that is ongoing,
- 01:58and for that I got tasked with
- 02:00evaluating 789 potchkin lymphomas
- 02:05and I thought.
- 02:07Nobody would be willing to work
- 02:09on this with me,
- 02:09particularly someone with a lab himself.
- 02:13But Abner has proved me wrong and has
- 02:17helped greatly in that translational study.
- 02:19What I didn't know about him until
- 02:22very recently is that he started
- 02:24his academic faculty position
- 02:26focusing on clinical hematopathology.
- 02:28And was not in fact in the lab when
- 02:30he asked those fundamental questions
- 02:33about pediatric type follicular
- 02:35lymphoma and that resulted in his Kay Ward.
- 02:37He later carried out these
- 02:39experiments in David Weinstock's lab.
- 02:41And I think it is this unique pathway
- 02:43that he has carved that demonstrates
- 02:45his scientific queries are truly
- 02:47grounded in his own personal clinical
- 02:49expertise and that is something
- 02:51that I find truly inspiring.
- 02:52So thank you so much for coming
- 02:54to speak at Yale Grand Rounds.
- 02:57Thank you so
- 02:57much for that really kind introduction
- 03:00and it's it's truly an honor and
- 03:02pleasure to be here in the department
- 03:05and thank Doctor Chu and Doctor Lu
- 03:07for hosting me in the department.
- 03:09I'm really happy to talk a little bit
- 03:11about some of the work that we've done
- 03:16just I have no disclosures and.
- 03:19I will talk about different,
- 03:22different efforts,
- 03:22but they all center around a
- 03:25central goal which is if you think
- 03:27about lymphoma or what we do as
- 03:29pathologists and classifying the
- 03:31over hundred types of lymphoma.
- 03:51And all the work that I'll be
- 03:53presenting has attempted to do is to
- 03:56identify biomarkers that can either
- 03:58predict or give us a sense of help
- 04:00us understand how different lesions,
- 04:03why different lesions respond differently
- 04:05to therapeutic interventions and the
- 04:07heterogeneity responses that we see
- 04:09even within a single disease entity.
- 04:12And then occasionally when you
- 04:13do the investigation,
- 04:14you end up finding that what
- 04:16was thought to be a part of an
- 04:19entity is actually its own entity.
- 04:21And so with that I'll start,
- 04:23I'll start each of these sections with
- 04:25sort of a clinical case that sort of
- 04:28represents the impact or of the work.
- 04:30So the first is a 25 year old man with
- 04:34isolated cervical lymph adenopathy
- 04:36limited stage with clonal CD10B cell
- 04:38population by flow cytometry and
- 04:40you can sort of see a confluence of
- 04:43expanded follicles and the sort of
- 04:45largest medium to largest sort of cells.
- 04:48And there's an architectural pattern to it,
- 04:51focular pattern.
- 04:52The neoplastic cells are CD10 positive,
- 04:55their BCL two mostly negative and have
- 04:57a really high proliferation fraction.
- 05:03And so traditionally when this was
- 05:07originally diagnosed, this case,
- 05:08it was diagnosed as a focal lymphoma and
- 05:10I'll talk a little bit about that for those.
- 05:13Not in familiar with lymphoma,
- 05:14but it was diagnosed as a high grade Grade
- 05:183 focal lymphoma and it was limited stage.
- 05:21And so the question there is do you
- 05:24treat with chemotherapy at the time
- 05:26or do you observe radiation therapy?
- 05:28And so we'll get back to the case,
- 05:31but just as a background focal lymphoma
- 05:33is a neoplasm of germinal center B cells
- 05:35comprised of centrocites and centroblasts,
- 05:37normal cell types within follicles,
- 05:40lymph node follicles.
- 05:41This disease demonstrates a
- 05:43policular growth pattern.
- 05:44The mean age is 6 decade and often
- 05:47presents with advanced stage disease,
- 05:50usually involving lymph nodes
- 05:52can occasionally involve marrow
- 05:54and extranodal sites.
- 05:56These follicular lymphomas can have
- 05:58different contributions of centrocytes,
- 06:00which are smaller cleave cells
- 06:03and larger centroblasts and today.
- 06:10Grade one to two would be sort of a lower
- 06:13grade and tends to have these smaller cells
- 06:16with sort of irregularly shaped nuclei.
- 06:19Whereas the central blasts are larger,
- 06:22more round with usually nuclear that
- 06:25are opposed to the nuclear membrane
- 06:27and 3A and 3D split between 3D
- 06:30being sheets of these large cells,
- 06:323A being more than 15 per high power field.
- 06:35And generally the thought is
- 06:37that the grade threes are.
- 06:39May have a behave worse and may it may
- 06:45require more aggressive chemotherapy
- 06:47and the current upcoming WHO grading
- 06:52has been removed and and and the ICC
- 06:55classification it's still there but
- 06:57for the purposes of this just want
- 06:59to present the difference so these
- 07:03focalformers have a fundamental genetic
- 07:05alteration which is BC L2 translocations.
- 07:09Which the 1418 which juxtaposes BC
- 07:12L2 upon regulatory enhancer elements
- 07:14of the heavy chain which causes
- 07:17up regulation of BC L2 expression
- 07:20which imparts survival advantage
- 07:22and it clinically we can see this
- 07:31expression representing a germinal
- 07:32center cell and you can see that in.
- 07:38Folk lympharma, traditional classic,
- 07:40folk lympharma, you have BCL two
- 07:42expression and traditionally the most
- 07:46folk lympharmas have a relatively low
- 07:49proliferation fraction and usually
- 07:51a reactive general center will have
- 07:53a very high proliferation fraction.
- 07:55And we can do additional studies to look at
- 07:58clonality like PCR for IGHD arrangements,
- 08:01fish for for to assess the the BCL
- 08:052 rearrangement and flow cytometry.
- 08:08Now early on we had identified there
- 08:11were some early series looking at folk
- 08:13and plumber and children and there
- 08:15there was some common trends noticed.
- 08:17So many of these young patients
- 08:21were were boys, young young boys.
- 08:24And there was they presented with
- 08:25limited stage disease often in
- 08:27the head and neck region,
- 08:28often had what was thought to be high
- 08:31histologic grade like more like a Grade 3
- 08:33or thought to be and they often lacked BC L2.
- 08:37Next question,
- 08:38but interestingly in all these
- 08:39series there was durable remission.
- 08:41Often these patients they'd get
- 08:43chemotherapy but sometimes they
- 08:45did not and and response was good.
- 08:49And so back in 2008 this was considered
- 08:51a provisional entity pediatric
- 08:53cochlemphoma with where you have these
- 08:55folkformers and kids that did well,
- 08:57they tended to have what they called
- 08:59grade 3 morphology expansive follicles,
- 09:02but it was clear that these
- 09:04pediatric cochlemphomas.
- 09:05Had many features indistinguishable
- 09:06from those seen in adults.
- 09:08And so at the time when I answered the field,
- 09:10there were some questions that came to mind.
- 09:12One is that as we got more
- 09:15and more experience,
- 09:15we realized that many of these patients
- 09:17had no progression or occurrence
- 09:18even with just excision of the node.
- 09:20And I began to see a lot of these cases
- 09:23presenting in patients with in their
- 09:2520s and 30s with the same features.
- 09:28So now the question is,
- 09:28are are these Grade 3 folliculars
- 09:30or the pediatric folliculars?
- 09:32And so we asked the question how
- 09:33can we actually distinguish these
- 09:34because it's going to actually
- 09:36make a big difference in care,
- 09:38how can we objectively define these.
- 09:39So we started by looking at 27,
- 09:42you know all the focal point of
- 09:44patients at MGH that were less than 40
- 09:46years of age and we found that they
- 09:48should have broke into two groups,
- 09:49one that were limited stage and
- 09:52one with advanced stage disease and
- 09:54the ones that were limited stage
- 09:56we did see a predominance in in in
- 09:59a male predominance.
- 10:01And we looked at a whole slew
- 10:03of pathological features to
- 10:05try to distinguish those.
- 10:06We did find that the the limited
- 10:08stage ones had large follicles
- 10:10and had a star sky pattern,
- 10:12but many of the other parameters
- 10:14didn't pan out to make a difference.
- 10:16But one thing that we noticed really made
- 10:18a difference was the BCL 2G arrangements.
- 10:20So all of the limited stage ones lacked BCL
- 10:23two arrangements and BCL 6 arrangements,
- 10:25and had a very high proliferation
- 10:27fraction greater than 30%.
- 10:29And they had the combination of them
- 10:31whereas the the Advanced Age ones,
- 10:34the majority did not have none of them
- 10:36had both and both of those features.
- 10:41So we thought well maybe this is something
- 10:43maybe maybe these two features the the,
- 10:45the BCL 2 gene arrangements and the
- 10:48proliferation fraction together could
- 10:49could pick these good behaving cases out.
- 10:52So then we looked at a second cohort of
- 10:54adult patients less than 40 years of age.
- 10:57Right. And we've broken them up
- 10:59into four categories, you know,
- 11:01translocation, no translocation,
- 11:02no translocation and high proliferation,
- 11:04low proliferation index and the
- 11:06ones that had no translocation
- 11:08and high proliferation fraction,
- 11:10all of them ended up being stage one disease.
- 11:14Many of them did get chemotherapy
- 11:16and in terms of progression relapse,
- 11:18none of them had progression or relapse.
- 11:20And actually I remember reading the notes
- 11:22and it would be like these surprising notes,
- 11:23Oh my gosh,
- 11:24this is patients doing really well and.
- 11:27And but this trend was really important
- 11:29to us and this is just a looking at
- 11:32Kaplan Meyer sort of curve showing
- 11:34the differences between the the cases
- 11:36that have BC L2 arrangements and High
- 11:38proliferation index and the ones that didn't.
- 11:40At the same time Elaine Jaffe's
- 11:43group described that these these
- 11:45pediatric follicular lymphoma cases.
- 11:49Had a very different morphology.
- 11:50So they're the morphology was not
- 11:52that of typical Centra blast where
- 11:54you can see these larger cells with
- 11:56these nucleoli sort of centers sort
- 11:59of touching nuclear membranes.
- 12:01They were more of a medium sized
- 12:03blastoid type phenotype and for that
- 12:05reason suggested that we shouldn't
- 12:07grade these these these cases.
- 12:08And when you look when we looked at
- 12:10all of our case at MGH we we found
- 12:12that there were two sort of peaks,
- 12:14so the pediatric type focal from a peak.
- 12:16Peaked in adolescence,
- 12:17but you can see that it tailed
- 12:20into adulthood versus.
- 12:23They took the classic focalforma which
- 12:25as we know peaks in the in the 6th,
- 12:277th decade,
- 12:28but it's in this intermediate range
- 12:31where it becomes important to be
- 12:33able to distinguish the difference.
- 12:37So from this we proposed that there was a
- 12:39highly indolent subset of focalforma which.
- 12:42Occurred in patients which were not likely
- 12:44to progress and did not require chemotherapy.
- 12:47Characterized by the lack of the B,
- 12:49CL2B, C,
- 12:49L6 arrangements and high
- 12:51proliferation fraction,
- 12:51and we hypothesize that they were
- 12:55biologically distinct and common in
- 12:57adolescents and young adults,
- 12:58but can occur in older patients.
- 13:01At the time,
- 13:02we were really excited about this,
- 13:04but we realized we saw a phenomenon that.
- 13:08You know,
- 13:08we hadn't really,
- 13:08we they were histologically similar
- 13:10to high grateful lymphoma in some ways
- 13:12and there was no direct evidence that
- 13:13the ones that occurred in adults were
- 13:15equivalent to the ones that occurred in kids.
- 13:17And practically speaking,
- 13:18we noticed,
- 13:19I noticed that a lot of patients
- 13:21who presented young patients,
- 13:23it depended their,
- 13:23their therapy depended upon who they saw.
- 13:25So if they saw a pediatric pediatric
- 13:27oncologist they would be quickly,
- 13:29they would be observed and
- 13:31they would do fine.
- 13:32And if they saw an adult
- 13:34oncologist they'd basically be
- 13:35given our chop and they would do fine.
- 13:37So we I thought it was important to go
- 13:39further to define these objectively so that
- 13:42basically to avoid unnecessary therapy.
- 13:45And so the question hypothesis is
- 13:46that pediatric type filial fund
- 13:48is biologically distinct and we
- 13:50wanted to look at the mutational
- 13:52profile differences between the two.
- 13:53Now to do this,
- 13:54we had to leverage colleagues from
- 13:56different institutions across the
- 13:58country to get these uncommon cases.
- 14:00So we put together 44 cases
- 14:03of limited stage disease,
- 14:04so we were not including
- 14:06advanced stage disease,
- 14:07no DLBCL and basically split them up
- 14:10into pediatric type focal components
- 14:11defined by the BC L2 rearrangement and
- 14:14high proliferation fraction versus the
- 14:16ones that either had BC L2 arrangement
- 14:18or locally low proliferation fraction.
- 14:22And we found when we did this again that
- 14:24the the ones that we call pediatric
- 14:26type had a had a male predominance were
- 14:29mostly involving the head and neck.
- 14:31And when we looked at the ones above
- 14:33older than 18 or younger than 18,
- 14:35which is the classic definition of pediatric
- 14:38and how sometimes these were defined,
- 14:40they had a similar breakdown male
- 14:42predominance and head and neck predominance.
- 14:45And in terms of therapy,
- 14:47a lot of the limited stage
- 14:50ones did get chemotherapy,
- 14:52the classic folk problems did
- 14:54get chemotherapy and radiation.
- 14:56A lot of the ones that were
- 14:58called PTFL did get excision,
- 15:01but the sort of rates were very different.
- 15:03So the the patients,
- 15:05the PTFL patients did really well with
- 15:08with remission no evidence of disease.
- 15:12Whereas the the the ones that were
- 15:14more classic had a BC L2 arrangement
- 15:17or high a low proliferation fraction
- 15:19were much more likely to recur and
- 15:22transformation events occurred
- 15:23solely in that group.
- 15:24This is a Kappa Meyer and when you
- 15:27looked at the breakdown between
- 15:29pediatric type in older patients
- 15:31and and less than 18 or older than
- 15:3318 the the the the the same trends
- 15:37occurred in terms of doing well.
- 15:40So we then looked at the the the
- 15:43molecular dynamics of these lesions
- 15:45and we found that the pediatric
- 15:48type colliculum informas had a very
- 15:51low genomic complexity with you
- 15:53know much fewer genome copy number
- 15:56alterations and genomic events
- 15:58than the typical for lymphomas.
- 16:00And there was a high higher predominance
- 16:03of loss of heterozygosity 1P36 and
- 16:05deletions at that site of TNFRSF 14.
- 16:09But the most striking thing was
- 16:11when we looked at the pediatric
- 16:14type whether lower than 18 or older
- 16:16than 18 that the classic.
- 16:18So we we did a targeted panel that
- 16:20included pretty much every gene
- 16:22that had been mutated reported to be
- 16:24mutated in focal form at the time
- 16:27and which was much more than here almost 100
- 16:34I think 100 genes.
- 16:35These these on the left are sort
- 16:37of the ones that are classically
- 16:39mutated in full lymphoma.
- 16:41And you can see that the even limited
- 16:44stage ones that had BC L2 arrangement
- 16:46or low proliferation fraction had a
- 16:48high frequency of these mutations.
- 16:50But they were essentially
- 16:52not present in the PTF,
- 16:53the pediatric type full lymphomas other than
- 16:58TNFTNFTNFRSF 14.
- 17:01We also did helexome on a on a on on
- 17:03six of the cases and we didn't find
- 17:05any recurrent mutations at the time.
- 17:07And this histogram just shows the purple
- 17:10and the blue represents 2 big subsets
- 17:12of typical classic focal FOMA and the
- 17:15most common mutations including ML,
- 17:18L2, probably PA,
- 17:19lot of chromatin modifying genes.
- 17:21And you can see that the the low
- 17:23frequency in the pediatric type
- 17:24focalforma other than the Tina,
- 17:25Tina, RSF 14.
- 17:26So we thought that they suggested
- 17:29definitely these were biologically distinct
- 17:32and we were pretty happy with that.
- 17:35And but we weren't clear what was driving
- 17:37the the pediatric type proliferation
- 17:38but at the same time we submitted
- 17:40to to blood and we're very excited.
- 17:42We we received a review saying well you
- 17:45only looked at six cases of whole EXIM.
- 17:47We think you should look up more
- 17:49and that was a little depressing
- 17:51at the time but it was turned
- 17:53out to be very fruitful and maybe
- 17:55appreciate the review process because
- 17:57we we basically sequenced all,
- 17:59the whole EXIM and all we found that.
- 18:01About 60% of these cases had
- 18:03mutations in the MAP kinase pathway,
- 18:05particularly MAP 2K1 at a
- 18:08a targeted hotspot site,
- 18:10which is present in this negative
- 18:14regulatory region of map 2K1 and represents
- 18:17a mutation that's commonly seen in
- 18:19other neoplasms including melanomas,
- 18:21****** hand cell hysterocytosis,
- 18:23B rap negative hairy cells,
- 18:26etcetera.
- 18:26So we were very excited about this and
- 18:28we thought this clearly demonstrated
- 18:30that these were biologically distinct.
- 18:33And at the time three groups were
- 18:35working on this simultaneously.
- 18:38And this is sort of a summary of
- 18:40all the cases in those three groups.
- 18:43You can see that again the common
- 18:46mutations typical and full lymphoma
- 18:48are very lowly are very rare in
- 18:51pediatric type and the map 2K1 and
- 18:53the MAP kinase pathway mutations
- 18:55really seem to be to drive the
- 18:57pediatric type molecular ones.
- 18:59The the one that is shared is
- 19:01the mutation of TNFRSF 14.
- 19:03So from this we you know we use
- 19:06the term pediatric type lymphoma
- 19:08to to include the fact that these
- 19:11occur in older patients.
- 19:12And you know from that that sort
- 19:15of helped define the current our
- 19:17current understanding of pediatric
- 19:19type of lymphoma and and in the
- 19:21DOUBLECHILD 2016 that was the help
- 19:24define the the characteristics.
- 19:26Some of the important features are
- 19:27that grading is not used for these
- 19:30for the reasons I mentioned there's
- 19:32never any advantage disease and
- 19:35there's no component of the LBCL.
- 19:37So if there is a if you see the
- 19:39LBCL that excludes this diagnosis.
- 19:41And the clinical implications that
- 19:43both children and adults with PTFL
- 19:45do not likely need chemotherapy when
- 19:47they're when they're diagnosed that
- 19:49way and the map kinase mutation may help,
- 19:52may help with the diagnosis.
- 19:53So going back to the patient I
- 19:55described that was originally
- 19:56diagnosed as grade three O 3,
- 19:58this was re diagnosed by Elaine Jaffe
- 20:02at at, at, at as pediatric type
- 20:05for lymphoma but at the site where
- 20:08the patient was being treated.
- 20:09They were still going to give
- 20:10our chop because they weren't
- 20:11familiar with this entity.
- 20:12And so I received a call from the
- 20:15mom about this and had seen the paper
- 20:17and I refer them to our ecology team
- 20:20who who basically were suggested
- 20:22observation and the patient's doing
- 20:24well and I still occasionally get calls
- 20:26from families about this where the
- 20:29the thought is to treat aggressively
- 20:32and they're always actually happy
- 20:34to to to feel like I've made some
- 20:37impact on the care of these patients.
- 20:39I just wanted to emphasize that
- 20:41it's really important to to follow
- 20:43all the criteria and this this
- 20:47case sort of demonstrates why.
- 20:49So this is a 25 year old with
- 20:52cervical lymphadenopathy,
- 20:54the nice space dot star sky pattern
- 20:56and the sort of blastoid type
- 20:59cells and these are CD10 positive
- 21:03with B cells with a relatively
- 21:06high proliferation fraction and.
- 21:09No BC L2 expression.
- 21:10So this was brought to me as a as a
- 21:12consult as whether this could be a
- 21:14nice classic case of pediatric type
- 21:16lymphoma and I asked you know did
- 21:18you do the fish for B CL2B C L6 and
- 21:21they didn't and it was frustrating
- 21:23for them but it after came back
- 21:26with ABC L6 gene rearrangement.
- 21:27So this is essentially a conventional
- 21:30BC L2 negative lymphoma.
- 21:32So it's not a pediatric type
- 21:34which and these do occur.
- 21:37And interestingly later there was
- 21:39you know months later there was a
- 21:40axillary lymph adenopathy and they
- 21:42re biopsied it because they were a
- 21:43little concerned by the diagnosis
- 21:44that it was not called pediatric type
- 21:46this time the the Falcons were much smaller.
- 21:50There was this eosinophil deposits and
- 21:53deposits that looked a little bit like
- 21:55Dutcher bodies and some of the cells,
- 21:57the cells were relatively small.
- 22:01The follicles were or small smaller
- 22:03again CD10 positive but this time
- 22:05the proliferation fraction was low
- 22:07and there was BC L2 expression.
- 22:09So clearly a case of classic
- 22:12classic folk lymphoma.
- 22:14So it's really important to follow
- 22:15all those guidelines and make
- 22:16the diagnosis of pediatric type.
- 22:18It's not just the BC L2 negativity.
- 22:22So from that you know we looked
- 22:25at several subtypes of folk
- 22:27lymphoma to to try to understand.
- 22:29Them and sort of the variation in in
- 22:32their behavior and I'll just mention
- 22:34while the other one which is the primary
- 22:37utaneous follicle central lymphoma
- 22:38which are localized skin lesions.
- 22:41They by definition don't are not
- 22:44systemic disease and they often
- 22:46occur in the head and the trunk.
- 22:48They have an excellent prognosis.
- 22:50Again they're negative for BC L2,
- 22:52they lack BC L2 rearrangements.
- 22:55So they're clear similarities to
- 22:57to pediatric type of lymphoma.
- 23:00So we wanted to investigate to see if
- 23:03we can understand understand these.
- 23:05We did, we did a study where we
- 23:09basically got primary continuous,
- 23:13continuous focal pharma and and
- 23:16secondary primarily being ones
- 23:18that occurred in the skin and
- 23:20actually and and not systemically.
- 23:22Initially there were four cases
- 23:23and we occasionally see this where
- 23:26it it fulfills the features of of.
- 23:28A primary utanous follicle center lymphoma,
- 23:30but then years later, months later,
- 23:32years later has systemic dissemination.
- 23:34So we had four of those.
- 23:36And then we also had secondary utanous
- 23:39follicle center lymphoma where there
- 23:41was a previous systemic disease
- 23:42involving the skin or they currently
- 23:45presented systemically and in the skin.
- 23:47And so the hypothesis that these
- 23:50would be genetically distinct and
- 23:52there may be initial differences.
- 23:55So you can see here that the median range,
- 23:57age range was approximately
- 23:59similar across these groups
- 24:03and in terms of therapeutic therapy
- 24:08was pretty it was pretty similar
- 24:11as well and the the patients with
- 24:13primary continuous fossil center
- 24:15of course did much better and but
- 24:17they they did they did recur as
- 24:20these as these cases do recur but
- 24:22the patients still do very well.
- 24:24One of the interesting things we noted
- 24:26was that the recurrences tended to
- 24:29occur at the similar same location.
- 24:32So you can see.
- 24:33You can see that here where the
- 24:35recurrences occurred pretty much at the
- 24:38same sites as the primary location,
- 24:40even the secondary recurrences.
- 24:42Whereas the the four cases that
- 24:46actually eventually recurred in a
- 24:50in a different site or were more.
- 24:52Groups presented systemically
- 24:54had quite interesting locations
- 24:56such as the dura breast and
- 25:02bone marrow, and so one of
- 25:05the things we noted was that
- 25:07these secondary cutaneous folk,
- 25:09the secondary cutaneous folk lymphomas,
- 25:12harbored a lot of the mutations
- 25:14in the chromatin modifying genes.
- 25:16Whereas again the primary cutaneous had
- 25:18fewer although they were more they were they,
- 25:21they occurred more frequently.
- 25:22I mean they they they had there were
- 25:25more cases than in primary pediatric
- 25:27type and that that had these but they
- 25:30were definitely much fewer than the
- 25:33secondary cutaneous folk lymphomas,
- 25:35the few cases that actually presented
- 25:39like primary cutaneous falcal,
- 25:41center lymphoma but then.
- 25:44Showed systemic involvement
- 25:46interestingly showed
- 25:49more frequent mutations in these
- 25:52chromatin modifying genes.
- 25:55So we proposed an algorithm to try to
- 26:00predict cases or to to help support
- 26:04cases that we that would potentially
- 26:07behave either at the time of diagnosis
- 26:10or later with systemic disease and.
- 26:13Basically the way it works is 1
- 26:16criteria is having both mutations in
- 26:19KMTTD and Kreb BP or having more than
- 26:23three chromatin modifier gene mutate,
- 26:25more than 3 mutations and chromatin modifier
- 26:28genes or the presence of BCLTG arrangement.
- 26:31And we found that if you had more than two
- 26:37of these two or more of these criteria
- 26:39that there was a very high risk.
- 26:41That this represented a lesion that
- 26:44was going to behave more systemically.
- 26:46And just to demonstrate this,
- 26:49these are few cases.
- 26:50This is 1 case of Prime Minister
- 26:53Falcon Center Oklahoma with that was
- 26:56had no BC L2 generated in the 74
- 26:58year old in the scalp and this had
- 27:01classic there was CD20 positive cells,
- 27:04somewhat of a high proliferation fraction.
- 27:07Again the cells were BC L2 negative.
- 27:09There was a relatively high,
- 27:11like I mentioned,
- 27:13proliferation fraction and there
- 27:15was no mutations in these in the
- 27:17common chromatin modifier genes.
- 27:19There was no B CL2B C L6 arrangement
- 27:22and this patient to the end of follow
- 27:25up never had any systemic disease,
- 27:28but there was.
- 27:29Here's another case of a 47 year
- 27:31old male who had a forehead lesion.
- 27:35The I HC showed terminal Center B cells,
- 27:37but these were BC L2.
- 27:40Positive there was no BC L2,
- 27:43B CL6GG arrangements.
- 27:45It was signed out as possible cutaneous
- 27:48falcocenter lymphoma primary but these
- 27:51this turned out to have mutations
- 27:54prebby P and KTM2D No B CL2B C L6
- 28:00arrangements and then imaging at
- 28:02the time showed concurrent nodal
- 28:04involvement and then there was a 45
- 28:06year old with a male scalp lesion.
- 28:09Again,
- 28:11no B CL2B C L6 arrangement
- 28:13signed out as possible primary
- 28:15cutaneous Falco Center lymphoma.
- 28:17Again this had Kreb BPKTMTD
- 28:21mutations and ABC L2 arrangement.
- 28:23The imaging at the time should not
- 28:25no concurrent nodal involvement,
- 28:27so it was thought to be a primary
- 28:29cutaneous Falco center lymphoma.
- 28:31But thirteen months later there was
- 28:32involvement of the bone marrow and
- 28:34axillary lymph node involvement.
- 28:35So I think,
- 28:36I mean there's still has to
- 28:37be validation for this,
- 28:38but I think these parameters can help
- 28:42in what can sometimes be a difficult,
- 28:46in some difficult cases and
- 28:47trying to predict,
- 28:48maybe even help support when
- 28:51these patients should be followed
- 28:53carefully for systemic disease.
- 28:55So to summarize some of these
- 28:59subsets that I've described,
- 29:00you have classic focal Pharma with B,
- 29:02CL2B, C L6 arrangements.
- 29:03And krubby P mutations and KTMTD mutations,
- 29:06other chromatin modifying G mutations
- 29:08with a low proliferation fraction.
- 29:11And then you have which is
- 29:13classic focal FOMA.
- 29:14You have pediatric focal FOMA
- 29:16which lacks the BCL two BCL 6 and
- 29:18lacks these chromatin modifying G
- 29:20mutations but has kinase mutations
- 29:22has a high proliferation fraction.
- 29:24These are most likely not arising
- 29:27from the typical.
- 29:28Recursive cell in the bone marrow
- 29:30and where which derives the
- 29:31systemic form of this,
- 29:33but it's probably represents
- 29:35a locally stimulated clonal
- 29:37follicular proliferation and
- 29:38similarly primary containers.
- 29:39Falconceno FOMA is is most likely
- 29:42locally stimulated focal lymphoma,
- 29:44but a subset of these that appear
- 29:47to be this way may actually be more
- 29:50have a more of a systemic behavior
- 29:52and I think looking at these
- 29:55mutations these underlying mutations
- 29:56may help predict those few cases.
- 29:59So you know,
- 30:02one runs against the one runs against the
- 30:05wall when really trying to identify
- 30:08biomarkers with basically pieces
- 30:10of tissue and characterizing,
- 30:12we can look at mutational profiles,
- 30:14but I began to think about ways that
- 30:18we can get around that in terms of
- 30:21looking at snapshots of mutational
- 30:24landscapes or expression profiles.
- 30:26Wanted to do more functional,
- 30:28be able to look at the more functional
- 30:30behavior of these cells in a context
- 30:32of microenvironment or be able to
- 30:34assess responses in therapy directly.
- 30:36And so began to think about models
- 30:38to do this and we started to develop
- 30:41patient derived xenograft models and
- 30:43we initially developed a repository
- 30:45where you know the lymphoma cases
- 30:47go to the frozen lab and we have a
- 30:50pipeline where tissues that are large
- 30:53enough that are not small biopsies.
- 30:55We can set aside some tissue and
- 30:57viably freeze that tissue and consent
- 31:00the patients and then in a very non.
- 31:03So we're not targeting any particular
- 31:05Histology or anything like that.
- 31:06We've done this for about 200 cases to
- 31:10date and it's been a very fruitful effort.
- 31:13It allows us because we're not
- 31:15going after specific histhologies
- 31:16to occasional to capture rare cases
- 31:19that if you were going to try to
- 31:21target that would be hard to do.
- 31:24And diagnostic challenging cases
- 31:26and the the viably frozen being able
- 31:29to viably freeze them allows us to
- 31:31then thaw them out and generate
- 31:33PDX models or try to culture them.
- 31:36So it's been great.
- 31:37So that's sort of our resource for this.
- 31:40And then the way we generate these
- 31:43PDX models is we use NSG immunity
- 31:46deficient mice and we initially we
- 31:48take those little pieces of tissue
- 31:50which you can see on the.
- 31:52On the on the right here that we
- 31:54viably freeze and we implant them
- 31:55underneath the capsule,
- 31:56the the renal capsule.
- 31:58So we pop out the kidney,
- 31:59we make a little hole and we stick the
- 32:01tissue in there and then eventually it
- 32:04grows into something on the bottom now.
- 32:06So you can see it just becomes a tumor
- 32:09and we can then take that and we
- 32:11can keep propagating that over time.
- 32:14And these models are very helpful because
- 32:15you can use them to test different therapies.
- 32:18And you basically are growing more
- 32:20tissue that you can then study live
- 32:25and so we use this recently for in in a
- 32:29more aggressive disease and again I'll,
- 32:31I'll I'll start with the case of
- 32:34a 42 year old man presented to the
- 32:36Ed with junction night sweats,
- 32:38anemia and basically a lot of
- 32:42disease lymphadenopathy.
- 32:43A biopsy was rendered and basically
- 32:47we have these sheets of very large
- 32:50cells with a lot of areas of necrosis
- 32:54and apoptosis and the cells had were
- 32:57large and had plasma blastic sort
- 33:00of phenotype with very prominent
- 33:02nucleoli and essentially placed nuclei.
- 33:05The cells were strongly out positive
- 33:08and lacked CD20 and CD3B cell and
- 33:10T cell markers and had some CD138.
- 33:14So essentially this was the diagnostic
- 33:17of positive large B cell lymphoma
- 33:20which is driven by overexpression of
- 33:23anaplastic lymphoma kinase which is
- 33:26which was reported fairly recently in 97.
- 33:29These are extremely rare lymphoma cases.
- 33:32They often do express plasma
- 33:35cell plasoblastic markers.
- 33:37They lack typical B cell T cell markers.
- 33:40The patients tend to be young,
- 33:41the median age.
- 33:42In the 40s, one third of them
- 33:44are in the pediatric age group.
- 33:46The the patient, the the prognosis
- 33:48is dismal and many patients die,
- 33:50especially in advanced stage
- 33:51with within a few years.
- 33:53And because of the rarity of the disease
- 33:55and the aggressiveness of the disease,
- 33:58it's essentially impossible to
- 33:59to set up a clinical trial.
- 34:02The the ALC anaplastic lymphoma kinase
- 34:05is a receptive tyrosine kinase originally
- 34:08discovered in anaplastic large cell
- 34:10lymphoma which is an op positive.
- 34:12T cell from a 94 and these
- 34:15are driven by fusions.
- 34:16The alcos of a LC L's driven by
- 34:19NPM fusions with with the kinase
- 34:23part of the ALC protein.
- 34:25But the alcosa large B cell from us
- 34:27tend to have the partner tends to
- 34:30be clathrin so different than the
- 34:32ALC L's and these lead to downstream
- 34:34signaling and Jack stat and P cell
- 34:36gamma and Ras irk Pi through kinase pathways.
- 34:42But you can see that the prognosis
- 34:44is pretty dismal for patients that
- 34:46particularly in advanced stage disease
- 34:50and there has been as you probably
- 34:53know ALK inhibitors developed for
- 34:55these malignancies all kinds of lung,
- 34:58all kinds of with without fusions and
- 35:01that have been fairly effective so
- 35:05soon after the discovery of these fusions.
- 35:08The the first generation OP inhibitor
- 35:10was was was generated and and and
- 35:13shown to be effective in in different
- 35:17positive neoplasms and then then
- 35:19there was second and third generation
- 35:21inhibitors that had higher potency.
- 35:23So interestingly in in AL positive
- 35:27anaplastic large cell lymphoma
- 35:28there has been that you you get a
- 35:31significant response right and to
- 35:33this to chrosatini which is the
- 35:35first generation OP inhibitor but.
- 35:36Where the out positive large B cell
- 35:38from is you actually these patients
- 35:41often go through a several sequential
- 35:44highly aggressive chemotherapy
- 35:45regimens and don't do well.
- 35:48And anecdotally people have tried
- 35:50the chrysotonyb and basically the
- 35:52patients have maybe had partial
- 35:54response and then essentially failure.
- 35:56And so the few cases that have been
- 35:59reported in the literature anecdotally.
- 36:01Have have have shown like a a
- 36:04very short response,
- 36:05a transit partial response and then
- 36:07failure and that's only been a couple.
- 36:10So that that had been the status of the
- 36:12field and these patients just don't do well.
- 36:15So the rationale for PDX modeling
- 36:17is that you know to to look at the
- 36:20efficacy of these OP inhibitors and
- 36:21the the fact is we can't do clinical trials.
- 36:23So could we use these models to test
- 36:26these OP inhibitors in this disease.
- 36:29So again this is just another image
- 36:32of how we make these.
- 36:33So you can see the small tumor
- 36:35and and basically
- 36:38we pop that back in and then we
- 36:39generate a tumor on the kidney,
- 36:41this actually is a tumor and out tumor.
- 36:45So on the left here you can see the
- 36:47normal kidney on the right these
- 36:49go pretty quickly and you can sort
- 36:50of see the size of the tumor and
- 36:52this is bivalve then you can see
- 36:54the the consistency of the tumor.
- 36:56You can see here that the PDX tumor
- 36:58actually expresses ALC and maintains the
- 37:00mean of phenotype of the native and the
- 37:02similarities between the Histology of
- 37:04the PDX ALC and the original patient.
- 37:08So this was originally we did this with
- 37:10the with a case that we captured through
- 37:13our pipeline and then we consent to
- 37:16the patient who agreed to only do this
- 37:17if we if we named the mask after him,
- 37:19which we did.
- 37:21So our approach was to implant the tumor
- 37:26and we we use ultrasound to actually
- 37:28check for engrassmans and then we we
- 37:30check at a second time point to to
- 37:32assess for growth and then we sort of
- 37:35split the mice between vehicle and latinum.
- 37:37So the question is we know that chrosotinum,
- 37:39we knew that Chrosotinum wasn't working,
- 37:41could second and third generation be helpful
- 37:44and so that's what we initially did so.
- 37:47So what we found,
- 37:48so this is ultrasound imaging and
- 37:49it's it's hard to tell but this is
- 37:51all tumor and this is all tumor.
- 37:53So there was large tumors at the
- 37:55time when we started therapy and you
- 37:57can see within within a week this on
- 38:00the right this is responsive therapy
- 38:02with most of this is like fibrotic
- 38:04tissue and on the left that's the
- 38:07disease and so on the right here
- 38:09you can see sort of the difference.
- 38:11So at day zero this is the time of
- 38:13therapy and you can see the ones
- 38:15that didn't get therapy.
- 38:16Grew,
- 38:17continued to grow.
- 38:18The ones that got therapy responded
- 38:20well and and and you can see by
- 38:22Western that the activity is,
- 38:24is is functional in terms on the access
- 38:27in terms of eliminating phosphorylation
- 38:30of ALK and some downstream signaling.
- 38:33And so then we went back to look
- 38:36at chrysatinib versus latinib and
- 38:38interestingly we found that yes
- 38:40in comparison to the vehicle which
- 38:42could grew after after therapy
- 38:44chrysatnib did have this little.
- 38:46Temporary stalling,
- 38:47but then grew out afterwards and
- 38:50then the Latin showed growth.
- 38:52So we're excited that the model
- 38:55was sort of mimicking what we were
- 38:57seeing in patients.
- 38:59We also tried a lectin A,
- 39:01which is another ALK inhibitor
- 39:04and found similar effect.
- 39:06So this is Jake Soumerai,
- 39:08who I work closely with as
- 39:10a clinical colleague.
- 39:11From our data we then he reached out
- 39:14to colleagues at different institutions
- 39:16who happened to have patients without
- 39:18B cell lymphomas for patients and
- 39:21they all had the ones that we could
- 39:24had the classerin alk fusion,
- 39:26many of them had been on prior therapies,
- 39:28a couple of them had been
- 39:30not responsive resotinip.
- 39:32So we put them on this therapy.
- 39:36So the one of the patients actually.
- 39:41Respond responded and is now in that
- 39:47at this point almost three years in
- 39:51clinical remission on the right you
- 39:53can sort of see what the patient
- 39:55initial disease and sort of after we
- 40:00had one patient who you know that the
- 40:03initial actually I should say the
- 40:04initial patient that we made the PDX
- 40:07out of responded and then recurred.
- 40:11And basically the transplants could
- 40:14not be performed in time and he passed.
- 40:17But since then the team has sort of
- 40:19realized the importance of getting
- 40:21the transplant done up front.
- 40:23So in summary, one of the patients,
- 40:25it's three years out and there's
- 40:27another young patient who was
- 40:29transferred to us who's now about
- 40:33one one year out in clinical remission,
- 40:36one of the patients had a partial remission.
- 40:39So from this we've initiated a small
- 40:45clinical trial to to get more cases
- 40:48and generate more PDX models to
- 40:50study this and other agents further
- 40:53and to also begin to look do some
- 40:56functional studies on on these cases.
- 40:58Interestingly I also really fascinated
- 41:00by class of plastic lymphoma
- 41:02because they were discovered.
- 41:04Around the same time in actually 1997,
- 41:06they, they have,
- 41:08they both have plasma blocks morphology,
- 41:11they have a very similar expression
- 41:13profile with the difference being the
- 41:15ALC because they're driven by ALC.
- 41:17The ALC largely cell phones
- 41:18drive by ALC fusions,
- 41:20the the plasma blocks forms are
- 41:21driven by Epstein Barr virus.
- 41:22So but I actually think that the
- 41:24biologies are probably pretty similar.
- 41:26There have been some evidence of
- 41:28the similar downstream signaling
- 41:30pathways being involved.
- 41:31So we we've started to view these
- 41:34as class obelastic type of fomas
- 41:36that have that both have sort of
- 41:39clinical clinically disciplined
- 41:40prognosis and no clinical trials.
- 41:42And we've actually set up models
- 41:45of these of class obelastic FOMA as
- 41:47well to begin to understand the the
- 41:50biology and develop new targets.
- 41:52And if you think about B cell develop
- 41:54B cell development starting with
- 41:56the Pro B cell and the bone marrow
- 41:58going into mature B cell.
- 42:01And then before you get to plasma
- 42:03cell where myelomas are derived
- 42:05from most of our mature B cell
- 42:08lymphomas are coming from you know
- 42:09the more mature B cell phenotype.
- 42:11There is a a very transient plastoblast
- 42:13phase where probably the plastoblast
- 42:15lymphomas and the up large B cell
- 42:18lymphomas arise and it it may be
- 42:20because these are so transient
- 42:22why these are are less common.
- 42:24But a very interested in sort of
- 42:26characterizing these in our models
- 42:27and understanding biology and
- 42:29coming up with new targets.
- 42:30Some of the questions we'd like to answer
- 42:33are what mediates these crozotinib
- 42:35failures in out large B cell lymphoma.
- 42:38We think that it may have to do with
- 42:42P glycoprotein where we know that
- 42:44crozotinib may be a a target for that.
- 42:48And then also what mediates resistance
- 42:51downstream after some time with
- 42:54the with the second and third
- 42:56generation OP inhibitors.
- 42:57And and it's interesting,
- 42:59I think it's fascinating that the
- 43:01ALK fusions actually are actually
- 43:03in part a better prognosis in the
- 43:05anaplastic large cell infomas better
- 43:06than the ones that don't have the ALK,
- 43:09whereas in the B cell infomas,
- 43:10it's in parts of dismal prognosis.
- 43:12So we're beginning to look
- 43:15at trying to understand.
- 43:17Whether those differences are different
- 43:19by the differences in in the fusion
- 43:21partners versus whether it's the native
- 43:23environment of B cell versus T cells.
- 43:24We have some experiments there to to
- 43:28look at that and and again trying to
- 43:31understand the silicon pathways that
- 43:33may be in parallel to plasma blast
- 43:35lymphomas to begin to develop some
- 43:36targeted therapies for that disease
- 43:38which there are none at the time.
- 43:41So for this part we you know we we basically.
- 43:45I found the the use of the second,
- 43:48the high the next generation of
- 43:50inhibitors in this disease and
- 43:52illustrate the potential of PDX
- 43:55models to inform therapeutic options
- 43:57for patients with REMALIGNANCIES.
- 44:03And you know more efforts are
- 44:05currently needed to look at adding
- 44:07electinim to low Latin to first line.
- 44:09So currently the NCCN guidelines
- 44:11have been modified to include.
- 44:13This as a go to after failure
- 44:16with first line therapies,
- 44:17but we're looking to begin to look at
- 44:20setting up a trial where these are
- 44:22included as part of the first line therapy.
- 44:25And then we've set up multiple
- 44:27lines of these at large B cell
- 44:29infomas and a plast cell infomas of
- 44:31Plast blast infomas to begin to do
- 44:33some of these functional studies.
- 44:34So I won't go through in detail
- 44:36with this last part,
- 44:38but one of the issues with lymphoma is
- 44:40that it's not a sheet of neoplastic cells,
- 44:42but there is a lot of microenvironmental
- 44:44cells that are actively interacting
- 44:46with the neoplastic cells.
- 44:47We know the landscape very well of
- 44:49the perform as I described initially,
- 44:51but we still can't explain the
- 44:53heterogeneity of the disease and the
- 44:55one thing that we can at this point
- 44:57know that is important is if patients.
- 45:00For this the proportion of patients
- 45:02that need therapy if they are,
- 45:04if they progress or relapse within
- 45:06two unit therapy they do really
- 45:08poorly and others do really well.
- 45:10But trying to find biomarkers earlier
- 45:12on to produce that is important.
- 45:14We think that understanding some elements
- 45:16of the micro environment may be important.
- 45:18So we begin to set up,
- 45:21we've we've set up models of focal
- 45:23fellow which are much harder than some of
- 45:25the aggressive lymphomas to begin to look at.
- 45:27The impact of genetic alterations in in
- 45:29the context of the microenvironment and
- 45:31what the interplay may be between the
- 45:33neoplastic cells and the microenvironment
- 45:37and the barriers again are having
- 45:39models for this and I'll just show
- 45:41you some of the pictures of the full
- 45:43and final model we've generated.
- 45:44So again this is a image
- 45:46of the tumor on the kidney.
- 45:49It's much more well circumscribed than
- 45:52some of the aggressive models here
- 45:53you can see that the cells are small,
- 45:55they look more like centrosized but.
- 45:57Mixed mixed morphology,
- 45:58one of the exciting things is that when
- 46:01you do when we look at the cells they
- 46:04include both B cells and the human T cells.
- 46:07So they they those two are present
- 46:09in the the tumor giving us an
- 46:11opportunity to begin to under to
- 46:13look at their interactions in vivo.
- 46:15This is just the immune chemistry showing
- 46:18the B cells and and T cells in the.
- 46:22In the tissue we do interestingly get
- 46:24some plasma acidic differentiation
- 46:26which you don't typically get in
- 46:28folk lymphoma but occurs in these
- 46:30models and we do get,
- 46:31we do get CD21 meshworks in this
- 46:33model although they don't persist
- 46:35and we believe that's because
- 46:37they're non non hematopoietic cells.
- 46:39So they persist for a period
- 46:40of time and go away.
- 46:41We we do get in NSG mice which don't
- 46:45have lymph nodes by definition.
- 46:47When we do the,
- 46:48when we do the PDX as we begin
- 46:50to see the generation of lymph
- 46:52nodes which is really interesting.
- 46:53So these these cells are tracking
- 46:56and into some residual primordial
- 46:58structure and generating lymph nodes
- 47:00and this just shows the B cells and
- 47:03the T cells within that and you do see
- 47:05some of this plasma state differentiation.
- 47:09We we do imaging to to to look at these.
- 47:12So this is normal kidney on
- 47:14the left and on the right.
- 47:19We'll see
- 47:24this, this dark thing is the tumor
- 47:26and we we developed this because
- 47:28unlike the large aggressive tumors
- 47:30where you can clinically sense when
- 47:32when the when the tumor is there,
- 47:35these are indolent.
- 47:36So we need some imaging to be able
- 47:38to detect engraftment and we're now
- 47:41working at colleagues at the road.
- 47:44Wignesh Shanmugam is close colleague.
- 47:47I'm working on spatial transcriptomics
- 47:49to begin to ask questions around the
- 47:52microenvironment and and the spatial
- 47:55relationships between the neoplastic
- 47:56cells and different subsets of the
- 47:59microenvironments and how that plays both
- 48:01in real patients but ultimately in the
- 48:04PD X's where we can do some manipulation.
- 48:08So I just want to make sure
- 48:09I don't out of time.
- 48:10So yeah, so in conclusion here we.
- 48:14We are,
- 48:16we are using you know paired human
- 48:19focal FOMA and focal PDX samples that
- 48:22characterize the the microenvironment,
- 48:24the clonal populations and to explore
- 48:26their nature and roll the crosstalk
- 48:29between these cell populations.
- 48:30And we anticipate that the INTRIVIAL
- 48:32model will serve as an ideal system to
- 48:35really interrogate focal formal biology
- 48:37and understand the mechanism mechanisms
- 48:39of targeted therapies and resistance.
- 48:43So with that I want to thank you for,
- 48:47for coming in person and
- 48:49for those who are on zoom,
- 48:51thank you for for listening
- 48:53and I'll take any questions.
- 49:03Very nice.
- 49:05Two questions Chris really like getting.
- 49:14It's
- 49:30about is now we know that uniquely
- 49:35starts by in that general center.
- 49:44Yeah, I mean presumably like the
- 49:47potentially the map kinase might
- 49:49be driving proliferation in those,
- 49:51that's one possibility and
- 49:53you know there have been
- 49:58you know people looking at micro
- 50:00RNAs and other other downstream.
- 50:03But we don't have a clear clearly that
- 50:05not it's not the same mechanism as
- 50:07having BCL two over express but that
- 50:09also may may be part of the reason why
- 50:11we never see systemic involvement by we
- 50:13don't see you know long term systemic
- 50:16involvement by these pediatric type.
- 50:17They're pretty limited and the you
- 50:19know to the point where there was
- 50:21a lot of debate about whether these
- 50:23should even be called lymphoma, right.
- 50:33Maybe I wonder where it's in
- 50:38on the OR the machinery. Yeah,
- 50:43yeah. There's no direct. Yeah.
- 50:45Second question I wanted to
- 50:46ask is on the latter app,
- 50:48the PDX is really pretty exciting
- 50:51to be able to use those.
- 50:54But you brought up from the end that
- 50:56you also want to look at the micro.
- 50:59Yes, you do get to. Have some of it
- 51:02in the future planted,
- 51:04but I think a lot of you guys,
- 51:05some of the issues are that for
- 51:09multiple passages that sort of
- 51:11leave that and you start winding up.
- 51:13Yes, yes. So, so I'm wondering if
- 51:16a lot of you guys explore which
- 51:20types of humanized type models.
- 51:24We're we're starting to to to
- 51:26look at the humanized models
- 51:27we've had it's a little bit,
- 51:29they're a little bit tricky to to
- 51:30use and they're extremely expensive.
- 51:32So you have to like you have to temper
- 51:34how you do things get this jump into it.
- 51:36And then we also in terms of match and
- 51:39we've tried to attempt to in our bank,
- 51:41we actually can prospectively
- 51:42collect blood from the patients who
- 51:45consent and so we've actually tried
- 51:47to think about matching those which
- 51:48takes some time and then you have to
- 51:50you know so we're working on that.
- 51:52It's a much harder experiment.
- 51:54Yeah. And you're right.
- 51:55Over time, it's a, you know,
- 51:57we do run into, you know,
- 51:58you lose like environment and how.
- 51:59Yeah.
- 52:01Thank you.
- 52:05Hi, can I ask you a question?
- 52:06This is Jeff Sklar on Zoom
- 52:11A2 part question. You know, I wonder
- 52:15about selection that's going on.
- 52:23Murders once they're established
- 52:25and compare the sequences of the
- 52:31yeah, we we do do that,
- 52:32we we do sequence them and do RN A/C
- 52:37to to compare and the the mutations
- 52:41that are present in the patient
- 52:43are typically present in the,
- 52:44although there are some.
- 52:47They're not 100% but they're
- 52:49pretty similar the the main
- 52:50chromatin modifying gene
- 52:57and so one of the points I was
- 53:00kind of getting at is do you ever
- 53:03see transformation to large cell
- 53:05in the rafted folliculars? Yes,
- 53:08we have. We have seen that in a in a few
- 53:11cases we can't get it to recurrently occur.
- 53:14So we'll have it as a.
- 53:15As an event and you know we're excited
- 53:17about the possibility of leveraging
- 53:19that to understand transformation,
- 53:21but it's it's hard to get as a
- 53:24recurrent issue as a you know,
- 53:26as a model of that transformation. Thanks.
- 53:38Yeah,
- 53:42very.
- 53:52Yes, yeah. Yes. Yeah,
- 53:57yeah,
- 54:02yeah. And that's also
- 54:03in my bucket in my mind.
- 54:05But I never really talked
- 54:06about it because no one knows,
- 54:07you know, it's so rare.
- 54:09But I really think that
- 54:10ultimately we're going to find
- 54:12that these have very similar.
- 54:14Analogy and if targets and in one,
- 54:18then my other question
- 54:28what are your thoughts really
- 54:30about this grading versus not.
- 54:35Yeah. So to be honest when
- 54:38I when I first joined
- 54:40the committee and having trained.
- 54:43With Nancy Harris.
- 54:44And I got onto the committee
- 54:46and the committee was like,
- 54:47we need to get rid of this grading.
- 54:49And my eyes were like,
- 54:52yeah, because that was like,
- 54:54yeah, I was like, wow.
- 54:56And I found myself defending really trying
- 54:58to defend the the point of grading.
- 55:00But then they made me see that, you know,
- 55:03with some of the newer targeted therapies
- 55:05that are being used, there is no.
- 55:08There's no difference really in in the
- 55:11patients that are 3A versus 1 to 2.
- 55:12And then the other thing is like
- 55:14I mentioned the POD24 where where
- 55:16patients that relapse or occur
- 55:18within two years they do much worse.
- 55:20And then the patients who don't,
- 55:22if you look at some of those papers
- 55:24they they they show you like in the
- 55:26supplements like the the the breakdown of
- 55:28these cases and there's an even number
- 55:30of grade one to two grade 3A in those.
- 55:32So it's actually not predictive of that.
- 55:34So I actually think there's a pretty
- 55:37good argument of not doing grading.
- 55:40I think the consensus of 3B is
- 55:44really more like DLBCL essentially,
- 55:45which is basically sheets of large cells.
- 55:47This happens to have follicles.
- 55:49So what the decision was was
- 55:51we would lose it.
- 55:52But usually when you think about
- 55:54making a change in a different way,
- 55:56show there's sort of this unwritten
- 55:57rule that you have to have data.
- 55:59To support it and interestingly for that,
- 56:00there is no data to talk
- 56:02about removing something,
- 56:03but it's almost like when you look at the
- 56:05origins of grading which was a little bit,
- 56:08there's not much data there.
- 56:10So it's and then the idea was
- 56:11like over time we'll figure it
- 56:12out but it never got figured out.
- 56:14So it's almost removing something
- 56:15that was never.
- 56:16So I think that's the,
- 56:17well what we did do is was
- 56:20suggest that grading be allowed.
- 56:22So it's,
- 56:23it's not required but at local
- 56:25institutions like ours where some of the
- 56:27oncologists really want the grading.
- 56:28We still have the grading,
- 56:29but we just wanted,
- 56:30I think the idea was to make it
- 56:31clear that it wasn't required.
- 56:32And I think that sort of the
- 56:35balance that we left were left with.
- 56:40Yeah, right, right.
- 56:45Thank you for the question.
- 56:55Are you looking for the DA sequence?
- 56:57Are you looking for the most of PCM who
- 57:00might support the transportation but
- 57:03have you snapped any translocation that.
- 57:08No. So there's no, there's
- 57:10usually no rearrangement.
- 57:11Igh would be the common partner,
- 57:16yeah no I I don't know of any.
- 57:18I know that there's some new
- 57:20technologies that are that can
- 57:21that can pick up some uncommon.
- 57:23Types of transvocations and we've thought
- 57:25about submitting some of these to that,
- 57:26but there's no evidence to date of any
- 57:29rearrangements in these in these lesions.
- 57:33So the second question regarding more
- 57:36general for the P7 coma, so really P7
- 57:41coma that have ITG and location is.
- 57:43So what is driving by the ITG from overreach?
- 57:49Right. So because the right now the
- 57:51uncle gene always replaced by the ITG
- 57:54which so it's high and expressed.
- 57:56So my thought is that we if we instead
- 58:01of becoming even the uncle gene which
- 58:04is coming out the ITG transporting
- 58:06the level you keep the water
- 58:10transportation uncle gene fashion low.
- 58:12You see that will be high in your strategy.
- 58:15So targeting, targeting the
- 58:17rearrangement you're saying.
- 58:18No talking even though globally
- 58:21and trying to reliable because
- 58:24this this model actually friendly
- 58:26controlled by the ITG reliable.
- 58:30Yeah no, I've never really thought
- 58:32thought about that interesting idea.
- 58:38Thank you.