BRCA1 and biliary tract neoplasm: Frequency of these mutations in GI tumors are still being elucidated but appear at a wide range dependent on the mutation and GI tumor (i.e., BRCA1 pancreatic cancer = 1.3–1.4%; BRCA2 pancreatic cancer = ~3%; BRCA1 biliary tract cancers = 1%; BRCA2 biliary tract cancers = 2%; etc.)[84].