Welcome to the Yale Cancer Center/Pathology Tissue Microarray Facility, a Cancer Center shared resource. We provide the university community with services related to tissue microarray technologies. Services are also available for the biotech and pharmaceutical industries.
These services include:
- Array design
- Slide distribution
- Technical support
- Cell line and tissue controls
What are tissue microarrays?
Tissue microarrays are produced by a method of re-locating tissue from conventional histologic paraffin blocks such that tissue from multiple patients or blocks can be seen on the same slide. This is done by using a needle to biopsy a standard histologic sections and placing the core into an array on a recipient paraffin block. This technique, originally described by in 1987 by Wan, Fortuna and Furmanski in Journal of Immunological Methods. They published a modification of Battifora's "sausage" block technique whereby tissue cores were placed in specific spatially fixed positions in a block. The technique was popularized by Kononen and colleagues in the laboratory of Ollie Kallioneimi after a publication in Nature Medicine in 1998. This technology should not be confused with DNA microarrays where each tiny spot represents a unique cloned cDNA or oligonucleotide. In tissue microarrays, the spots are larger and contain small histologic sections from unique tissues or tumors.
An example of a tissue microarray and its construction
The arrays are assembled by taking core needle “biopsies” from specific locations in pre-existing paraffin-embedded tissue blocks and re-embedding them in an arrayed “master” block, using techniques and an apparatus developed by Konenen et al. In this way, tissue from 600 specimens can be represented in a single paraffin block.
The arraying device is designed to produce sample circular spots that are 0.6 mm in diameter at a spacing of 0.7-0.8 mm. The surface area of each sample is 0.282 mm2, or in pathologists’ terms, about the size of 2-3 high power fields. The number of spots on a single slide is variable depending on the array design, the current comfortable maximum with the 0.6 mm needle is about 600 spots per standard glass microscope slide.
Once a TMA is constructed it can be used for quantitative analysis. AQUA technology measures the actual level of protein in the cells by fluorescence. This is a much more sensitive and specific way to measure proteins for more specialized chemotherapeutic treatment.