Significance of Thymidine Phosphorylase/Platelet‐derived Endothelial Cell Growth Factor in Carcinoma of the Papilla of Vater

The expression of thymidine phosphorylase (TP) in carcinoma of the papilla of Vater was studied to clarify its significance in tumor progression and in determining prognosis. Fifty‐nine cases of surgically resected carcinoma of the papilla of Vater were studied. Immunohistochemical staining was performed to evaluate the expression of TP, microvessel count and p53 overexpression. TP expression was demonstrated in tumor cells in 62.7% (37/59) of the cases. A higher frequency of regional lymph node metastasis was found in TP‐positive tumors than in TP‐negative tumors (P=0.006). TP‐positive tumors were more advanced than TP‐negative tumors with regard to clinical stage (P=0.035). TP‐positive tumors had significantly higher microvessel density (27.6±10.1) than TP‐negative tumors (20.4±10.0, P=0.01). Moreover, TP expression was significantly correlated with a poor prognosis (P=0.02). These suggest that in carcinoma of the papilla of Vater, TP production by tumor cells is correlated with tumor progression through its regulatory effect on neovascularization.