KRAS and colorectal cancer: Of the RAS isoforms, KRAS is the most frequently mutated (85%), followed by NRAS (12%) and HRAS (3%).4 KRAS mutations are prevalent in approximately 20% of all human cancers, with particularly high frequencies observed in pancreatic ductal adenocarcinoma (PDAC; 88%), colorectal cancer (CRC; 50%), and non-small cell lung cancer (NSCLC; 32%).5 KRAS mutations typically manifest as activating mutations commonly occurring as single nucleotide substitutions, predominantly in four hotspot codons: 12, 13, 61, and 146.