KRAS and adenocarcinoma: In the multivariate logistic regression analysis, non-adenocarcinoma (OR, 1.553; P = 0.035), right colon (OR, 1.626; P = 0.008), well and moderate differentiation (OR, 2.227; P = 0.002) and positive CA19-9 (OR, 1.591; P = 0.030) were independent factors for predicting KRAS mutations.