KRAS and colorectal carcinoma: Subsequently, somatic gain-of-function v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) [and v-raf murine sarcoma viral oncogene homolog B1 (BRAF)] mutations have been identified as reliable and strong negative predictors for the response to anti-EGFR treatment in CRC (1–6).