What is KRAS Mutational Analysis?

KRAS Mutational Analysis looks for 14 mutations in the KRAS gene.  The current clinical literature indicates that colorectal adenocarcinomas harboring mutations in the KRAS gene have been associated with a lack of response to therapy with cetuximab and panitumumab.

Which of my patients can be tested with KRAS Mutational Analysis?
It is up to the discretion of physicians to determine when to order KRAS Mutational Analysis. KRAS Mutational Analysis can provide important information for colorectal cancer patients that might be candidates for cetuximab or panitumumab targeted therapy against EGFR.

On what type of malignancies can KRAS Mutational Analysis provide information?
KRAS Mutational Analysis can be performed on patients with colorectal denotation. The analysis can be performed on either formalin fixed paraffin-embedded (FFPE) and/or fresh frozen samples as long as there is a minimum of 2mm of 100% tumor or 4 mm of 50% tumor or an equivalent combination thereof.

Exactly what type of testing is performed with KRAS Mutational Analysis?
Through DNA sequencing, KRAS Mutational Analysis detects the 14 most frequent KRAS mutations in codons 12, 13, and 61, identifying greater than 99% of tumor mutations.

What are the studies supporting KRAS Mutational Analysis?
The following two studies have demonstrated that the presence of a KRAS mutation was associated with a lack of response to cetuximab in patients with colorectal adenocarcinoma:

• 1- Khambata-Ford, S., et al., Expression of epiregulin and amphiregulin and KRAS mutation status predict disease control in metastatic colorectal cancer patients treated with cetuximab. J Clin Oncol, 2007. 25(22): p. 3230-7.
• 2- Lievre, A., et al., KRAS mutations as an independent prognostic factor in patients with advanced colorectal cancer treated with cetuximab. J Clin Oncol, 2008. 26(3): p. 374-9.

The following study has shown that the presence of a KRAS mutation was associated with a lack of response to panitumumab in patients with colorectal adenocarcinoma;

• 1. Amado, R.G., et al., Wild-type KRAS is required for panitumumab efficacy in patients with metastatic colorectal cancer. J Clin Oncol, 2008. 26(10): p. 1626-34.

The following study shows KRAS mutations are found in approximately 37% of colorectal cancers:

• 1- Andreyev, H.J., et al., Kirsten ras mutations in patients with colorectal cancer: the multicenter "RASCAL" study. J Natl Cancer Inst, 1998. 90(9): p. 675-84.

What are the specimen requirements for KRAS Mutational analysis?
KRAS mutational analysis can be performed on FFPE tissue. Submit one paraffin block or 6 unstained uncharged slides cut at 4 microns each, containing at least 50% tumor from the patient’s most recent surgery or biopsy. We request tissue that has not previously been frozen (for intraoperative consultation) unless there is no other available tissue. A sample should contain 100% tumor in a 2 mm diameter sample or 50% tumor in a 4 mm sample, or an equivalent combination thereof. Please include a copy of the patient’s corresponding pathology report.

How do I order KRAS Mutational analysis?
Please contact us at 1-800-901-5177 and inquire about KRAS Mutational Analysis ordering information. Client Services will provide a KRAS Mutational Analysis paraffin block shipper or assist you in using your own shipping materials. For timely results, please do not ship the day before a holiday.

What type of report will I receive?
KRAS Mutational Analysis results are integrated in an easy to interpret report. Each report provides detailed information on a patient’s tumor, confirming which, if any of fourteen (14) potential mutations are present or absent.

What is the turnaround time for KRAS Mutational Analysis?
Once we receive the tissue specimen or slides and required forms, analysis takes approximately 7 days.

Is KRAS Mutational Analysis reimbursed?
KRAS Mutational Analysis is reimbursed by Medicare and other third party payors. Caris Dx will bill third party payors for KRAS Mutational analysis and there are no out-of-pocket costs for the patient, except for co-pays or deductibles as required by law or the patient’s insurance plan.

Will my office need to obtain prior authorization from the patient’s insurance company prior to ordering KRAS Mutational Analysis?
If required, prior authorization should be obtained before submitting a specimen. Caris Dx can help you obtain this information.

Who do I call for additional information or with questions on the KRAS Mutational Analysis?
Please call us at 1-800-901-5177.