KRAS and neoplasm: Mutations of the APC, K-ras and p53 genes were detected in one (2.4%), three (7.3%) and 15 (36.6%) of the 52 cases of C-Ca with differentiated-type tumours, respectively, and 16 (20.0%), five (6.3%) and 20 (25.0%) of the 82 cases of D-Ca with differentiated-type tumours, respectively.