BRAF and cancer: CRC has a high prevalence of mutations in the mitogen-activated protein kinase pathway (MAPK pathway), including neuroblastoma ras viral oncogene homolog (NRAS) and Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) sequence variations in roughly 50% of cancers and the v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation, which is seen in 10%.