In colon and rectal carcinoma (CRC), KRAS is also found predominantly in a mutated isoform (45 %), whereas NRAS mutations are infrequent (in 7.5 % of CRC) and HRAS mutations have not been detected.4 RAS proteins act as molecular switches alternating between an active, GTP‐bound state and an inactive, GDP‐bound state. This evidence concerns the gene KRAS and colorectal carcinoma.