KRAS and colorectal neoplasm: [1]  Patients whose tumors harbor a mutation in codons 12, 13, or 61 of the KRAS gene do not benefit from cetuximab or panitumumab. Data are mixed whether the presence of a KRAS mutation in colorectal tumors is prognostic (i.e. whether it influences patient outcomes independent of treatment).  KRAS mutational analysis is also used to refine prognosis and treatment decisions in patients with non-small cell lung cancer (NSCLC) and is under investigation as a prognostic and/or predictive factor in other malignancies.