Immunohistochemical Expression of Thymidine Phosphorylase in Human Endometrial Cancer

Abstract Objective. To investigate correlations between the expression of thymidine phosphorylase (TP) by endometrial cancer cells and the density of microvessels within the tumor, the clinicopathologic features, and the prognosis. Methods. We examined tumor specimens obtained from 46 patients with endometrial cancer (9 FIGO stage IA, 16 stage IB, 8 stage IC, 1 stage IIA, 6 stage IIB, and 6 stage IIIC). The cellular expression of TP and the intratumoral density of microvessels were determined by immunohistochemistry using monoclonal antibodies to TP and factor VIII-related antigen, respectively. We investigated the relationship between the cellular expression of TP and the following factors: clinicopathologic features (menopausal status, histologic type, tumor size, histologic grade, myometrial invasion, cervical invasion, and metastasis), the microvessel count, and the disease-free survival period. Results. Of the 46 tumors, 19 (41%) were TP-positive. The microvessel count was significantly higher in TP-positive tumors than in TP-negative tumors ( P = 0.01, Mann–Whitney U test). There was no significant correlation between TP expression and clinicopathologic features, and there was no significant difference in the disease-free survival period between patients with TP-positive tumors and patients with TP-negative tumors. Conclusion. TP expression was not correlated with clinicopathologic features or prognosis, but was associated with an increased density of microvessels in endometrial cancer. These findings suggest that TP may play an important role in angiogenesis and may be involved in the tumorigenesis of endometrial cancer.