Dahl Chase Folders

FISH for ALK Gene Rearrangements

Reference Number: AA-00433

ALK (2p23) Gene Rearrangement

Clinical Significance:

Recently established guidelines from the American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP), and/or the American Society of Clinical Oncology (ASCP) recommend testing for all newly diagnosed non-small cell, non-squamous lung carcinomas or such metastatic lung carcinomas that have not had a primary resection available for testing.  ALK (2p23) gene rearrangements can be found in 2-7% of non-small cell lung carcinomas (NSCLC), more commonly in adenocarcinomas of never or light smokers, whose tumors lack EGFR and KRAS mutations.  ALK gene rearrangements, due to fusion with various other genes (such as ALK-EML4) render the tumors sensitive to ALK inhibitors; such as crizotinib (while resistant to EGFR tyrosine kinase inhibitor therapies)


Specimen Requirements and Collection:

Formalin fixed tissue containing a sufficient amount of tumor (generally at least several mm of tumor tissue submitted in the tissue block). 



Fluorescent in-situ hybridization (FISH)


Molecular pathology requisition form


Send formalin-fixed, paraffin-embedded (FFPE) tissue and cell block containing tumor at room temperature.  Also acceptable 10-unstained, 4-5 micron slides with 1 post H&E.  Please include a surgical pathology report

Unacceptable specimen:

Specimens fixed in alternative fixatives or metal fixatives (ex. B-plus).  Decalcified specimens.

Reference Range:

ALK gene rearrangement present = positive result

ALK gene rearrangement not detected = negative result

CPT codes:


Test reported:

Results are reported within 7-10 days