Ki-67 and p53 protein expression was evaluated immunohistochemically in 32 patients with intrahepatic, extrahepatic bile duct and gallbladder carcinomas, who underwent surgery at First Department of Surgery, The University of Tokushima School of Medicine. p53 expression was found more in the well differentiated group than poorly differentiated group (p=0.007). MIB1 labelling index (MIB1 LI) was higher in EHC than in GBC (p=0.0061). MIB1 LI (T), (MIB1 LI in tumor) was higher in cases with lymph node metastasis than in those without lymph node metastasis (p=0.0189). Moreover, MIB1LI (L) (MIB1 LI in metastasized lymph node) was higher in poorly differentiated than in well differentiated carcinoma (p=0.0404). Prognostically, patients with high MIB1 LI (T) (>56.93) had a worse prognosis after surgery than those with low MIB1 LI (T) (p<0.05). There was no association between p53 positive tumors and MIB1 expression. These results suggest that cancer cell proliferative activity was markedly increased in cases with EHC compared to those with GBC and the poorly differentiated and lymph node metastasis group. MIB1 LI in tumor was found to be a good prognostic indicator whereas there was no association of p53 positive tumor with MIB1 expression and prognosis of the patients
