Expression of the proliferative cell nuclear antigen (PCNA) in adenocarcinoma of the gallbladder, and its relationship to prognosis.

Proliferative cell nuclear antigen (PCNA) has been correlated with degree of differentiation in some tumours, but information on PCNA expression in adenocarcinoma of the gallbladder is currently limited. Therefore, we examined PCNA expression in adenocarcinoma of the gallbladder, and its relationship to prognosis. The expression of PCNA was studied by immunohistochemistry in 70 formalin-fixed, paraffin-embedded specimens of surgically removed adenocarcinomas of the gallbladder. The percentage of stained nuclei was recorded, and the PCNA-labelling index (LI) was expressed as the ratio of labelled nuclei to the total number of nuclei counted. In all histological types, the PCNA-LI in the invasive zone of the tumour was higher than that in the luminal zone of the tumour (p < 0.05). The PCNA-LI showed a stepwise increase with decreasing degrees of differentiation in both the invasive and the luminal zone of the tumour (p < 0.01). In advanced adenocarcinomas, patients whose tumours had a PCNA-LI of less than 35 in the invasive zone had significantly longer survival rates than those with PCNA-LI equal to or greater than 35 (p < 0.01). Multivariate analysis, using the Cox proportional hazards model, indicated that a PCNA-LI > or = 35 in the invasive zone of the tumour was a significantly unfavourable prognostic factor (p = 0.002). The PCNA-LI of routinely processed specimens of adenocarcinoma of the gallbladder may be helpful for the evaluation of cell proliferation and prognosis.