• Test Code:
  • Department:
  • Test Synonyms:
    KRASKRAS Gene Mutation (exons 1, 2)
  • CPT Code(s):

Colorectal adenocarcinomaKRAS gene mutations are present in approximately 35% of cases and correlate with resistance to treatment with cetuximab.1   For patients whose tumor is positive for a KRAS mutation, treatment with anti-EGFR monoclonal antibody therapy is not recommended based on the Provisional Clinical Opinion issued by the American Society for Clinical Oncology.2
Non-small cell lung carcinoma (NSCLC) - KRAS gene mutations are present in approximately 30% of cases and correlate with a worse progression-free survival as compared with tumors harboring EGFR mutations.3


1. Microscopic examination of the specimen and macrodissection of tumor-rich areas.
2. DNA extraction and purification.
3. PCR amplification of KRAS coding exons 1 and 2.
4. Screening for mutations by one of two methods, depending on tumor cellularity.

a. Real-time PCR with high resolution melting curve analysis (HRM). DNA sequencing is used to confirm any potential mutations identified by this approach.

b. Bidirectional Sanger sequencing

i.  An LNA-modified oligonucleotide is included to suppress wild-type allelic amplification (LNA-sequencing).

5. Estimated sensitivity:
          a.  20% mutant allele for HRM.
          b.  1% mutant allele for LNA-sequencing (used for samples with low tumor cellularity)
6. Estimated specificity: 99.5% of KRAS mutations reported in colorectal carcinoma.

Specimen Requirements:

  • A paraffin block or
  • 10 unstained sections of tumor (4-5 microns) (15 sections for small biopsies)

Contact Client Services for shipping materials and procedrues at (855)535-1522

A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES.  Please include detailed clinical information.

Test Performed (Days):

Mon - Fri

Turn Around Time:

7 - 10 days

Shipment Sensitivity Requirements:

  • Keep specimen cool during transit, but do not ship on dry ice.
  • Please use the cold pack provided in the KDL shipping kit.
  • Ship the specimen overnight express, using the FedEx priority overnight label provided. 
  • Contact Client Services for shipping materials and procedures at (855) 535-1522.


  1. Loupakis F, Ruzzo A, Cremolini C, Vincenzi B, Salvatore L, Santini D, Masi G, Stasi I, Canestrari E, Rulli E, Floriani I, Bencardino K, Galluccio N, Catalano V, Tonini G, Magnani M, Fontanini G, Basolo F, Falcone A, Graziano F. KRAS codon 61, 146 and BRAF mutations predict resistance to cetuximab plus irinotecan in KRAS codon 12 and 13 wild-type metastatic colorectal cancer. Br J Cancer. 2009 Aug 18;101(4):715-21.
  2. Allegra CJ, Jessup JM, Somerfield MR, et al. American Society of Clinical Oncology Provisional Clinical Opinion: Testing for KRAS gene mutations in patients with metastatic colorectal carcinoma to predict response to anti–epidermal growth factor receptor monoclonal antibody therapy. J Clin Oncol. 2009 Apr 20;27(12):2091-6.
  3. Brugger W, Triller N, Blasinska-Morawiec M, Curescu S, Sakalauskas R, Manikhas GM, Mazieres J, Whittom R, Ward C, Mayne K, Trunzer K, Cappuzzo F. Prospective Molecular Marker Analyses of EGFR and KRAS From a Randomized, Placebo-Controlled Study of Erlotinib Maintenance Therapy in Advanced Non-Small-Cell Lung Cancer. J Clin Oncol. 2011 Nov 1;29(31):4113-20.

Additional Info:

The Knight Cancer Institute at Oregon Health & Science University is a pioneer in the field of precision cancer medicine. The institute's director, Brian Druker, M.D., helped prove it was possible to shut down just the cells that enable cancer to grow. This breakthrough has made once-fatal forms of the disease manageable and transformed how cancer is treated. The OHSU Knight Cancer Institute is the only National Cancer Institute-designated Cancer Center between Sacramento and Seattle – an honor earned only by the nation's top cancer centers. It is headquarters for one of the National Cancer Institute's largest research collaboratives, SWOG, in addition to offering the latest treatments and technologies as well as hundreds of research studies and clinical trials.

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