Plasma bcl-2 and nitric oxide: possible prognostic role in patients with metastatic breast cancer

Interest in translational studies on breast cancer is presently devoted to identifying biological predictors of disease prognosis and response to treatment. In this study, we determined the plasma levels of bcl-2 and nitric oxide in 45 patients with metastatic breast cancer using an ELISA technique and correlated them with clinical and biological factors that may affect the outcome of disease. The results were as follows. The mean level of bcl-2 was 278.44 +/- 383.2 U/L compared with 64.42 +/- 14.4 U/L (p = 0.007) for controls. Levels of bcl-2 were higher in patients less than 50 yr old, premenopausals., GIII tumors, positive nodes, ER positive tumors (p = 0.6, 0.5, 0.9, 0.4, and 0.005, respectively). The site of metastatic disease and the number of metastatic sites did not show statistically significant influences over bcl-2 levels. Furthermore, there was a trend, although not significant, toward improvement of survival in patients with higher levels of bcl-2. The mean level of the nitric oxide (NO) was 297.12 +/- 220.54 microM compared with 13.91 +/- 1.1 microM for controls (p = 0.003). The levels were higher in patients over 50 yr, postmenopausal patients, those with visceral deposits, grade III tumors, positive lymph nodes, and those with disease-free survival of less than 6 mo following primary treatment (p = 0.1, 0.2, 0.1, 0.09, 0.4, and 0.08 respectively). Furthermore, there was no correlation between NO levels and survival (r = 0.002). This study demonstrates a potential role for NO and bcl-2 as prognostic factors in patients with metastatic breast cancer. However, larger studies with more patients together with a comparison of serum levels (ELISA) and tissue levels (MOAb) are still required.