KRAS and colorectal carcinoma: While KRAS A18D and L19F, and BRAF mutations other than V600E were rare in large CRC cohorts (each <1%) (Giannakis et al., 2016, TCGA, 2012), NF1 mutations have been reported in ∼5% of cases and successful validation as a predictive marker in randomized trials could spare these pts ineffective treatment.