KRAS and colorectal cancer: KRAS mutations, most of which (84%) occur at G12, resulting in single amino acid substitutions that activate the oncoprotein by hindering its ability to hydrolyze GTP, were detected in various solid tumors, such as lung cancer (~25% of cases), colorectal cancer (~35% of cases), and pancreatic cancer (~95% of cases), affecting an estimated 147,000 patients per year in the US 19,20.