In the six patients with biliary tract cancer, the following mutations were detected: KRAS in one patient (16.7%), TP53 in five (83.3%), CDKN2A in four (66.7%), SMAD4 in three (50.0%), and CDKN2B in two (33.3%; Table 6). The gene discussed is KRAS; the disease is biliary tract neoplasm.