RET (10q11) 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. RET (10q11) gene fusions can be found in 1-2% of NSCLC, more commonly in adenocarcinomas of never or light smokers, whose tumors lack EGFR and KRAS mutations. Patients with RET gene rearrangements, characteristically due to KIF5B–RET, CCDC6–RET, NCOA4–RET, and TRIM33–RET fusion, rendering the tumors sensitive to RET inhibitors such as cabozantinib (while resistant to EGFR tyrosine kinase inhibitor therapies).
https://www.nccn.org/professionals/physician_gls/pdf/nscl.pdf
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).
Methodology:
Fluorescent in-situ hybridization (FISH)
Forms:
Molecular pathology requisition form
Transport:
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:
RET gene rearrangement present = positive result
RET gene rearrangement not detected = negative result
CPT codes:
88377
Test reported:
Results are reported within 7-10 days