Bcl-2 expression is a prognostic factor in the subgroups of patients with colorectal cancer

The prognostic significance of Bcl-2 expression in colorectal cancer has been intensively studied, however, the results were controversial in the whole group of colorectal cancer patients. We proposed that one of the main reasons for such controversial results may be that Bcl-2 played variable roles in the subgroup of patients. We, therefore, investigated the prognostic importance of Bcl-2 expression by using immunohistochemistry in the various subgroups of 147 patients with colorectal cancer. Among these tumours, 85 (58%) expressed Bcl-2 protein and 62 (42%) were negative. Bcl-2 expression was positively related to DCC expression (p=0.0002). Survival analyses in the subgroups of the patients showed that lack of Bcl-2 expression was related to a worse prognosis in the male patients (p=0.02) but not in female patients (p=0.53), in the patients with DNA diploid tumours (p=0.005) not in the patients with non-diploid tumours (p=0.46), and in the patients with ras negative tumours (p=0.01) not in the patients with ras positive tumours (p=0.25). Bcl-2 expression was not related to prognosis in the total group of the patients (p=0.20). In conclusion, Bcl-2 protein may play variable prognostic roles in the subgroups of the patients with colorectal cancer. Analysis of Bcl-2 expression in the tumour may be of value in predicting prognosis and therapeutic response.