ALK FISH

Formalin-fixed, paraffin-embedded tissue blocks; fixed in 10% neutral-buffered formalin for at least 6 hours, and not more than 72 hours. Tissue should be prepared in sections at 4 microns thick. Sections should be mounted on the positive side of an organosilane-coated slide in order to minimize detachment of the tissue from the slide during FISH assay. EDTA decal specimens are accepted.

ALK encodes receptor TK (intracellular) that can fuse with amino terminus portion of other genes. Present in 4-5% nonsmall cell carcinomas, primarily adenocarcinomas.EML-ALK fusion generates activated protein TK that is involved in inhibiting of apoptosis, promotion of proliferation and has shown sensitivity to crizotinib (Xalkori).

Pathology Report

Ambient temperature (20-25°C); refrigerated samples acceptable); exposure to acids, strong bases or extreme heat should be avoided.

Specimen not verified for the presence of invasive carcinoma and specimens fixed in fixatives other than formalin are not acceptable. Surgical pathology report should be included. Acid decalcification compromises the specimen quality. Use EDTA for decalcification.

FFPE - 10 years

Only tissue that is clearly invasive carcinoma (established by histopathologic criteria) should be tested. Selection of tissue for the FISH assay should be performed by a pathologist. In non-FFPE specimens, presence of tumor cells should be verified by a pathologist.