In the present study, the expression of protease indicated by cathepsin B (CB) and the expression of extracellular matrix indicated by laminin (LN) and tenascin (TN) was immunohistochemically examined in 25 gallbladder carcinomas. The incidence of expression of .CB and TN in normal epithelium was 1/25 (4%) and 0/25 (0%), respectively, and significantly increased in carcinomas (14/25 : 56% and 21/25 : 84%, respectively) (p<0.01). The LN expression was detected in the basement membrane of all normal epithelium, and the incidence of LN expression was significantly decreased in the carcinomas (7/25: 28%) (p<0.01). The incidence of CB expression in poorly differentiated adenocarcinomas (1/8: 13%) was significantly lower than that in papillary, welland moderately differentiated adenocarcinomas (11/15: 74%) (p<0.01). However, these responses were not significantly related with other histologic features or nuclear DNA ploidy pattern. The LN expression of the hepatic metastasis group (4/6 :67%) was significantly greater than that in the non-metastatic group (3/19 :16%) (p<0.05). The expressions of CB, LN and TN were not associated with the postoperative prognosis. In conclusion, the increased expressions of CB and TN, and the decreased expression of LN were cancerassociated alterations. The expression of CB was correlated with the histological grade of differentiation, and the expression of LN was correlated with the hepatic metastasis
