CPT® Code 81311

NRAS (neuroblastoma RAS viral [v-ras] oncogene homolog) (eg, colorectal carcinoma), gene analysis, variants in exon 2 (eg, codons 12 and 13) and exon 3 (eg, codon 61)

Molecular genetic testing is a critical procedure used to identify specific mutations in the NRAS (neuroblastoma RAS viral [v-ras] oncogene homolog) gene, particularly focusing on variants located in exon 2 (codons 12 and 13) and exon 3 (codon 61). This gene is situated on chromosome 1 and plays a significant role in the development of colorectal cancers. The NRAS gene encodes a membrane-bound protein that possesses GTPase activity, which is essential for regulating cell signaling pathways. Mutations in the specified regions of the NRAS gene can disrupt the intrinsic pathway responsible for RAS-GAP mediated GTP hydrolysis, leading to aberrant activation of the epidermal growth factor receptor (EGFR) signaling cascade. This disruption is crucial as it contributes to the processes of malignant cell proliferation, invasion, metastasis, and neovascularization. The identification of these mutations through genetic testing is particularly important for individuals diagnosed with colorectal carcinoma, as it aids in evaluating the potential effectiveness of targeted monoclonal antibody therapies, such as cetuximab and panitumumab. These therapies work by binding to the EGFR, thereby inhibiting the downstream signaling pathways that promote tumor growth and spread.