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

Transcript

• 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.