Immunohistochemical Characteristics of Biliary Tract Carcinoma and Its Precancerous Lesions

Kim, Jiyoung; Park, Youngnyun; Kim, Hogeun

Abstract

Carcinomas of the biliary tract are known to be more common in East Asia than in Western countries, but their exact histopathological characteristics and tumorigenesis are not well elucidated. To examine the histological and immunohistochemical characteristics of the biliary tract carcinomas according to their anatomical sites and to elucidate their tumorigenesis, we performed histological review and immunohistochemical study in a total of 135 cases of biliary tract carcinomas; 24 intrahepatic bile duct, 34 gallbladder, 51 common bile duct, and 26 periampullary carcinomas. Precancerous lesions were associated with 5 (20.8%) cases of intrahepatic duct carcinomas (dysplasia 5), 7 (20.6%) cases of gallbladder carcinomas (adenoma 5, dysplasia 2), 10 (19.6%) cases of common bile duct carcinomas (adenoma 7, dysplasia 3), and 2(7.7%)cases of periampullary carcinomas (adenoma 2). Immunohistochemically, c-erbB-2 expression in gallbladder carcinoma (21/34, 62%) was significantly higher than that of intrahepatic (8/24, 33%). Ki-67 indices were higher in common bile duct carcinomas (19%) than those of intrahepatic bile duct (14%) or periampullary carcinomas (12%). Overexpression of p53 gene product in the periampullary carcinomas (20/22, 77%) was higher than that of intrahepatic (12/24, 50%) or common bile duct carcinoma (26/51, 51%). In the precancerous lesions the c-erbB-2 expression was present in 29% of the gallbladder, 20% of the intrahepatic, 10% of the common bile duct precancerous lesions and none of the 2 cases of adenomas in the periampullary region. The p53 overexpression in the precancerous lesions was frequent, ranging from 43% to 60%. These results suggest that a mechanism involving p53 gene mutation and c-erbB-2 gene activation is present in the tumorigenesis in a significant number of the biliary tract carcinomas and they may be the early events in the tumorigenesis of the biliary tract carcinomas.