ROS1
(6q22) 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. ROS1 (6q22) gene
rearrangements can be found in 1-2% of non-small cell lung carcinomas
(NSCLC), more commonly in adenocarcinomas of never or light smokers, whose
tumors lack EGFR and KRAS mutations. ROS1 gene rearrangement with common fusion
partners include: CD74, SLC34A2, CCDC6, and FIG, and are associated with
responsiveness to oral ROS1 tyrosine kinase inhibitors (TKIs).
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:
ROS1 gene
rearrangement present = positive result
ROS1 gene
rearrangement not detected = negative result
CPT codes:
88377
Test
reported:
Results are reported within 7-10 days
