KRAS (CODONS 12 & 13)
Gene Symbol: KRAS
Chromosomal Locus: 12p12.1
Protein: KRAS - V-KI-RAS2 Kirsten Rat Sarcoma Viral Oncogene Homolog
Pseudonyms: KRAS1; KRAS2; RASK2; C-RAS
TURNAROUND TIME: 8 days
2012 AMA Code: 81275
TESTING METHODOLOGY: Polymerase chain reaction (PCR) followed by mutation specific analysis of codons 12 and 13 of the K-ras gene (KRAS).
Collect: Tumor specimen containing at least 30% tumor mass. 5-6 unstained slides with 3-4 uM thick tissue sections. Must be accompanied by a pathology report and an H&E slide with the tumor regions clearly identified.
- Transport: Specimen should be shipped at Room Temperature (No Saturday delivery
- Unacceptable Conditions: Stained slides.
Counseling and informed consent are recommended for genetic testing. A consent form
is available as a resource but not required.
Inheritance: Somatically acquired.
Colorectal Cancer: KRAS is mutated at codon 12 or 13 in 30%-40% of colorectal carcinomas.
Non-Small Cell Lung Cancer: KRAS is mutated at codon 12 or 13 in 20-25% of non-small cell lung carcinomas.
Disease Characteristics: Tumors that have a KRAS mutation at codon 12 or 13 will not respond to anti-EGFR inhibitor drugs.
Molecular Genetic Mechanism: Somatic mutations can occur at any of the 6 nucleotides that comprise codons 12 and 13 of the KRAS gene.
Clinical Sensitivity: The tissue sample submitted for testing must contain at least 30% tumor. The assay will detect as low as a 3% population of mutant cells.
Analytical Sensitivity: 97%
Test Limitations: Mutations that are not at codons 12 and 13 will not be detected. This test is only for somatic KRAS mutations in cancer tissue. Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
Indications for Use:
- To predict the effectiveness of EGFR-targeted drugs in a chemotherapy protocol on colon or non-small cell lung cancer.