NCIt definition : A change in the nucleotide sequence of the KRAS gene that that results in constitutive
signal transduction, which stimulates downstream signaling pathways involved in cell
growth, proliferation, invasion, and metastasis. The presence of KRAS activating mutations
in colorectal cancer and non-small-cell lung cancer is used identify the subgroup
of patients who are most likely to respond to EGFR antagonist chemotherapy.;