KRAS (Codons 12 & 13)

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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).
 
SPECIMEN REQUIREMENTS:
 
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.
A Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information.
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
 
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.
 
Related Tests: EGFR gene and BRAF codon 600
 
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.
ADDITIONAL REFERENCES:
OMIM - Lung Cancer: http://omim.org/entry/211980
Genetics Home Reference: www.ghr.nlm.nih.gov/gene/KRAS