Expression of thymidine phosphorylase correlates with microvessel density in prostate cancer

Angiogenesis in the growth and development of prostate cancer was the focus of this study. Various angiogenic factors and their clinicopathologic correlations with the progression of prostate cancer have been examined. Thymidine phosphorylase is identical to platelet-derived endothelial cell growth factor (TP/PD-ECGF) and has angiogenic activity. We investigated the expression of TP/PD-ECGF in prostate cancer and its association with angiogenesis or clinicopathologic findings in 81 cases with prostate cancer. Western blot analysis using a specific monoclonal antibody 654-1 revealed the existence of a 55 kDa TP/PD-ECGF protein in human prostate cancer tissue. Cancer tissue showed low-positive immunostaining in 32 cases (39.5%) and high positivity in 49 cases (60.5%). This protein expression indicated a statistically significant association with microvessel density (low vs. high TP/PD-ECGF expression group: mean ± SD, 37.3±27.0 vs. 53.1±28.0 microvessels in three fields, p<0.05). No correlation was found between the expression of TP/PD-ECGF and nuclear grade, glandular differentiation, clinical stage or overall survival rate. TP/PD-ECGF may play an important role in tumor angiogenesis in prostate cancer tissues. Although the expression of TP/PD-ECGF was not correlated with clinical outcome in patients with prostate cancer, there remains the possibility that TP/PD-ECGF may support or modify the tumor growth through angiogenesis in cooperation with other factors.