KRAS Mutation
Detection
Clinical
Significance:
The American Society of Clinical Oncologists (ASCO), ASCP, CAP, AMP, and
National Comprehensive Cancer Network (NCCN) recommend routine testing for RAS mutation at diagnosis of stage IV
disease and all colorectal carcinomas considered for therapy with cetuximab or
panitumumab, either alone or in combination with other anti-cancer agents.
https://www.nccn.org/professionals/physician_gls/pdf/colon.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). The KRAS test
utilized by our laboratory will detect mutations as long as they constitute at
least 10% of the DNA sample population.
Methodology:
DNA isolation and extraction, library prep, and next-generation
sequencing (NGS) for hotspot mutations KRAS
exon 2, 3, and 4
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:
KRAS mutation
not detected = negative result
KRAS mutation
detected = positive result
CPT codes:
88381, 81275, 81276, 81403, G0452
Test
reported:
Results are reported within 7-10 days