Prevalence of low-penetrance KRAS (codons 12/13 and 61) and BRAF mutations in metastatic colorectal carcinoma.

e14147 Background: In patients with metastatic colorectal cancer (mCRC), activating mutations within KRAS, which result in EGFR-independent intracellular signal transduction activation, are found in approximately 35-40% of patients with mCRC have been significantly associated with lack of response to cetuximab or panitumumab therapy. Although current guidelines recommend testing for frequent KRAS codons 12/13 mutations, emerging data indicate that additional KRAS and BRAF mutations are also predictive of non-responsiveness to anti-EGFR antibodies in mCRC. This study is aimed to analyze the prevalence of low-penetrance KRAS and BRAF V600 mutations in caucasian mCRC population. Methods: A two-institution retrospective cohort of 1,238 consecutive KRAS wild type mCRC patients previously studied for 7 mutations in codons 12/13 (G12D, G12A, G12V, G12S, G12R, G12C and G13D) by the CE-IVD marked ARMS-scorpion real-time polymerase chain reaction PCR (Therascreen, Qiagen) was assayed by the diagnostic TaqMelt PCR a...