KRAS and neoplasm: These relatively rare mutations, as well as codons 12 and 13 mutations, are responsible for the oncogenic constitutive activation (Buhrman et al, 2007; Feig and Cooper, 1988) of RAS/RAF/MAPKs pathway and they might account for up to a 10% of resistant patients bearing KRAS codons 12 and 13 and BRAF wild-type tumours.