KRAS and colorectal cancer: While the frequency of mutations and the ras family gene that is mutated varies by cancer type, approximately 30% of all human cancers harbour a mutation in a ras gene with mutations most frequently occurring in KRAS. KRAS mutations occur in more than 90% of pancreatic adenocarcinomas, in approximately 40% of colorectal cancers and 33% of non- small cell lung carcinomas (NSCLC) [4].