The most frequent somatic KRAS mutation in NSCLC is KRAS G12C, which is also common in colo-rectal cancer (KRAS G12C results from nucleotide transversion with a guanine (G) replaced by a thymine (T) at coding position 34 GGT->TGT (c.34G>T) leading to replacement of amino acid glycine (G) to cysteine (C) (p.Gly12Cys). Here, KRAS is linked to rectal cancer.