High frequency of K-ras mutations in biliary duct carcinomas of cases witha long common channel in the papilla of vater

The frequency of K-ras mutation in biliary duct carcinomas in different loc ations and the relationship to the form of the junction of the pancreaticob iliary duct (JPBD) are not understood clearly. These points were investigat ed in the present study. Thirty-seven biliary duct carcinomas in patients w ithout anomalous JPBD were investigated for K-ras mutations. Regarding loca tion, 12 were hilar, 4 in the upper, 11 in the middle, and 10 in the lower portion of the duct. Furthermore, with 14 cases for which the form of the J PBD could be confirmed by endoscopic retrograde cholangiopancreatography or postoperative cholangiopancreatography, division was made into two types: those with a long common channel (>5 mm) in the papilla of Vater (type 1, n = 4), and the other with a shorter or nonapparent common channel (type 2, n = 10), The overall frequency of K-ras mutation was 30%, the incidence gra dually increasing from upper to lower regions. K-ras mutations were signifi cantly more frequent in biliary duct carcinomas associated with long common channels (P < 0.05). These results suggest that a long common channel may bear a relation to K-ras mutations in biliary duct carcinogenesis, presumab ly through its influence on pancreatic juice regurgitation.