KRAS is a gene that encodes one of the several proteins in the epidermal growth factor receptor (EGFR) signaling pathway that is important in the development and progression of cancer. KRAS can harbor oncogenic mutations that yield a constitutively active protein. Such mutations are found in approximately 30% to 50% of metastatic colorectal tumors and are common in other tumor types. Mutations in the KRAS gene may indicate poor prognosis and poor drug response with therapies targeted to EGFR. The absence of a KRAS mutation predicts a greater likelihood of response to EGFR-targeted therapies and improved survival with such treatment. The relevant KRAS mutation is in one of five codons (12 13, 61, 117 or 146). The presence of KRAS mutations in codon 12, 13 or 61 is associated with a high likelihood of resistance to therapies targeting EGFR. In addition, mutations at codons 117 and 146 may also be associated with reduced response to EGFR-targeted therapies. Results should be interpreted in conjunction with other laboratory and clinical findings. Drug resistance: Panitumumab Cetuximab

KRAS belongs to the RAS family of oncogenes. In lung, KRAS mutations are detected in approximately 20% to 25% of adenocarcinoma and less than 10% of squamous cell carcinoma which demonstrate a minor glandular component. KRAS mutations in NSCLC most often occur in codons 12 or 13 and with a lower frequency in codon 61. Mutations in KRAS are usually mutually exclusive with other oncogenic driver aberrations including EGFR, BRAF, HER2 mutations and ALK and ROS1 rearrangements. Contrary to most other oncogenic driver mutations, KRAS is more often found in smokers and is detected at lower frequency in East Asian patient cohorts. The prognostic as well as predictive role of KRAS mutations continues to be studied. Although various attempts inhibiting KRAS have been made, there is no established therapy specific for this large patient subpopulation. Recommend correlation with other clinical and lab findings.

KRAS belongs to the RAS family of oncogenes. KRAS mutations are detected in approximately 20% to 25% of lung adenocarcinoma. Contrary to most other oncogenic driver mutations, KRAS is more often found in smokers and is detected at lower frequency in East Asian patient cohorts. Mutations in KRAS are usually mutually exclusive with other oncogenic driver aberrations including EGFR, BRAF, HER2 mutations and ALK and ROS1 rearrangements. KRAS mutations in NSCLC most often occur in codons 12 or 13 and with a lower frequency in codon 61. The prognostic as well as predictive role of KRAS mutations continues to be studied. Although various attempts inhibiting KRAS have been made, there is no established therapy specific for this large patient subpopulation.

Pancreatic ductal adenocarcinoma (PDAC) is initiated by oncogenic mutant KRAS, which has been shown to drive pancreatic neoplasia. More than 90% of pancreatic ductal adenocarcinoma samples have a KRAS mutation which may have prognostic, and (with ongoing trials assessing the efficacy of novel KRAS inhibitors) possibly therapeutic implications. However, targeting KRAS directly has been difficult in these tumors.

KRAS mutations are infrequent in gastric carcinomas and have been reported in approximately 6% of cases. Studies have shown no statistically significant difference in survival between KRAS-mutated and KRAS-non-mutated gastric carcinomas. However, one study showed a trend that the presence of a KRAS mutation was associated with better overall survival in gastric carcinoma patients. There is an increased frequency of KRAS mutations in gastric carcinomas with microsatellite instability. In gastric cancer, the predictive ability of KRAS has not been extensively studied, but a small study did not demonstrate an effect on survival in patients treated with an EGFR inhibitor.