Increased polycomb-group oncogene Bmi-1 expression correlates with poor prognosis in hepatocellular carcinoma

Purpose Recent studies have identified polycomb-group gene Bmi-1 as oncogene in the generation of mouse pre-cell lymphomas, and overexpression of Bmi-1 has been found in several human tumor with the disease progress and poor prognosis of the cancer patients. Methods In present study, we investigated Bmi-1 expression and its prognostic significance in hepatocellular carcinoma (HCC) by performing immunohistochemical analysis, using a total of 137 HCC clinical tissue samples. Results High Bmi-1 expression (Bmi-1 2+ or 3+) was shown in 29.9% cases. The positive immuno-staining of Bmi-1 was not only in well/moderately-differentiated tumor cells, but also in surrounding noncancerous or cirrhotic liver tissue. Bmi-1 expression level did not correlate with any clinicopathological parameters. However, survival analysis showed that the high-Bmi-1 group had a significantly shorter overall survival time than the low-Bmi-1 group (P = 0.047). Multivariate analysis after 24 months revealed that Bmi-1 expression was a significant and independent prognostic parameter (P = 0.002) for HCC patients. Conclusion Our study indicated that Bmi-1 could be a candidate biomarker for long-term survival in HCC.