Download KRAS Gene Mutation Analysis

KRAS Gene Mutation Analysis
DESCRIPTION
The v-Ki-ras2 Kirsten rat sarcoma (KRAS) gene encodes a small GTPase that functions in a signal transduction
cascade downstream of the epidermal growth factor receptor (EGFR). KRAS somatic mutations have been
identified in 30-40% of colorectal cancers and 10-30% of non-small cell lung cancers. The most common
mutations reported are in KRAS codons 12 and 13. Several studies have demonstrated that tumors carrying
any of these mutant forms of the KRAS gene are less likely to respond to EGFR inhibitors. Clinical guidelines
now recommend KRAS testing before starting anti-EGFR therapy. The KRAS Gene Mutation Analysis assay is
able to differentiate between the following 7 most common mutations and the wild-type form of KRAS
codons 12 and 13:
Gene
Mutation
KRAS
KRAS
KRAS
KRAS
12GGT>AGT
12GGT>GAT
12GGT>GTT
12GGT>TGT
Amino Acid
Change
G12S
G12D
G12V
G12C
Gene
KRAS
KRAS
KRAS
Mutation
12GGT>GCT
12GGT>CGT
13GGC>GAC
Amino Acid
Change
G12A
G12R
G13D
SPECIFICATIONS
IG Labs Test Code
118
Turnaround Time
24-48 hours
PCR/Probe Targets
Mutations within codons 12 and 13 of the v-Ki-ras2 Kirsten rat sarcoma (KRAS)
gene and an endogenous control.
Specimen
Formalin-fixed, paraffin-embedded blocks/slides
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2-3 10-micron sections
Storage: Ambient (4°C preferred)
Sections must be freshly prepared or less than 3 months old.
Causes for Rejection
DNA quality can be compromised due to nucleic acid fragmentation, and/or
modification by chemical reactions between formaldehyde and nucleic acids
which include crosslinking with proteins or other biomolecules. Specimens with
endogenous control Ct values greater than 30 cycles will be deemed as
Quantity/Quality Not Sufficient (QNS) and are noted as such.
Limit of Detection
2% mutant content (Validated in Formalin-fixed paraffin embedded cell line
studies)
Detection Range
Reaction
Ct Value
Endogenous Control
20 - 30
KRAS Detection
Above Baseline < 35 cycles
Samples with a 35 Ct value are approaching the lower limits of detection for the assay.
Method
Quantitative Real-Time Polymerase Chain Reaction (qPCR)
CPT Codes
81275, 81403
References
1.
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10.
Allegra C.J., et al. J Clin Oncol (2009), 27:2091-2096.
Amado R.G., et al. J Clin Oncol (2008), 26:1626-1634.
Baldus, S.E., et al. Clin Cancer Res (2010), 16:790-799.
Eberhard D.A., et al. J Clin Oncol (2005), 23:5900-9.
Jackman D.M., et al. Clin Cancer Res (2009), 15:5267-5273.
Lievre A., et al. Cancer Res (2006), 66: 3992-3995.
Massarelli E., et al. Clin Cancer Res. (2007), 13:2890-2896.
Pao W., et al. PLosMed. (2005), 2:e17.
ASCO Provisional Clinical Opinion. J Clin Oncol (2009), 27.
College of American Pathologists Perspective on Emerging Technologies – KRAS Mutation Testing for
Colorectal Cancer (CRC), September 2009.
11. National Comprehensive Cancer Network - NCCN Clinical Practice Guidelines in Oncology November
2008.