Tissue specimens used by various projects supported by the Core often need to be sectioned by microtomes and mounted on glass slides for histological examination. This may be for review by a pathologist, either to verify the presence of a lesion or to localize microscopic regions to be analyzed. Some molecular biology techniques, such as PCR, may also be performed directly on histological preparations. The tissue specimens are cut and processed for histological examination by histotechnicians on a fee-for-service basis. This service is easy to coordinate with the other activities of the Core because the MBSPSC is located within the Pathology Department, in a room adjacent to that where the histotechnicians are working. Most of the tissue samples are from fixed archival specimens but a similar service is available for frozen specimens.

Many projects supported by the MBSPFC depend on accurate microdissections of tissue samples in order to ensure that the material being studied is enriched for a particular cell type or disease of interest. For example, some of the projects supported by the Core during the last funding cycle involved mutational analyses of the p53 gene in cancers from patients with and without exposure to a specific environmental agent such as tobacco. Given that cancer cells are often admixed with dense stroma as well as with inflammatory cells in vivo, it is important to identify areas enriched for cells of interest in tissue specimens and to separate them from surrounding cells before performing the appropriate molecular biological tests. It is often necessary in such cases to also identify areas of the tissue samples that are devoid of cancer cells and to be able to isolate cells from those areas as well for controls. The MBSPFC is equipped with a laser capture microdissecting instrument where histological tissue sections (from either frozen or fixed, archival specimens) can be examined microscopically and areas of interest can be targeted with a laser beam. The heat generated by this beam melts a thin polymer film that is placed over the tissue, which makes it adhere to the underlying cells that can then be lifted and separated from surrounding cells. This allows microdissections of tissue areas with a resolution of 35 microns in diameter. Dr. Dubeau, the director of the MBSPFC, a surgical pathologist, has the expertise needed to either perform the microdissections or to guide users interested in this core function.