KRAS Somatic Mutation Analysis, Tumor

Casandra

Casandra Test Code MC55341Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID KRASPCPT Codes 81275, 81276, 88381

KRAS Somatic Mutation Analysis, Tumor

Clinical Use

Use

This test is useful for detecting molecular markers associated with response or resistance to specific cancer therapies. Monoclonal antibodies against epidermal growth factor receptor (EGFR), such as cetuximab and panitumumab, represent an area of targeted therapy for patients with colorectal and non-small cell lung cancer (NSCLC). However, studies have shown that not all individuals with colorectal cancer or NSCLC respond to EGFR targeted molecules. As altered KRAS constitutively activates the RAS/MAPK pathway downstream of EGFR, agents such as cetuximab and panitumumab, which prevent ligand-binding to EGFR, do not appear to have any meaningful inhibitor activity on cell proliferation in the presence of altered KRAS. Current data suggest that the efficacy of EGFR-targeted therapies in colon cancer and NSCLC is confined to patients with tumors lacking KRAS mutations.

Special Instructions

A pathology report (final or preliminary) must accompany the specimen for testing to be performed. The report must include the patient name, block number (must be on all blocks, slides, and paperwork) and date of tissue collection.

Limitations

This assay is designed to detect variants in KRAS codons 12, 13, 61, and 146 (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T). It has not been clinically validated for use as a tool to monitor response to therapy or for early detection of tumors. This test cannot differentiate between somatic and germline alterations. Not all patients whose tumors have wildtype KRAS respond to epidermal growth factor receptor (EGFR)-targeted therapies. Rare genetic alterations may lead to false-negative or false-positive results.

Test Details

New York Approved