Expression of bcl-2 protein in lymphocytes of patients with laryngeal carcinoma

The aim of this study was to evaluate the expression of bcl-2 protein in lymphocytes of the peripheral blood of patients with laryngeal carcinoma. The protein product of the proto-oncogene bcl-2 is a physiological inhibitor of apoptosis or programmed cell death. Since we believe that apoptosis is involved in the regulation of an immune response to a cancer process, we tried to show how this mechanism works in laryngeal carcinoma in comparison with normal peripheral blood lymphocytes of healthy controls. To explain the significance of this molecule’s expression, we used flow cytometry to examine the expression of bcl-2 in T lymphocytes from the peripheral blood of 23 patients with laryngeal carcinoma and 20 healthy controls. Our study revealed that the expression of bcl-2 protein in T lymphocytes from the cancer patients was significantly higher than in the controls (P < 0.05). This difference in the expression of bcl-2 protein was found in both CD4 and CD8 subpopulations and was significantly higher than in the control group. In patients with laryngeal carcinoma expression of bcl-2 protein in T lymphocytes was higher in CD4 than in CD8 cells (P < 0.05). These results suggest that bcl-2 protein may interact in the regulation of apoptosis of lymphocytes, taking part in anti-cancer defence. Received: 26 September 1998 / Accepted: 17 February 1999