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