Expression of Platelet‐derived Endothelial Cell Growth Factor/Thymidine Phosphorylase in Human Bladder Cancer

We investigated the expression of platelet‐derived endothelial cell growth factor/thymidine phosphorylase (PD‐ECGF/TP) in primary bladder cancer, its association with clinicopathologic findings, and their prognostic value. mRNA was extracted from 20 bladder cancer specimens and 6 normal bladder mucosal tissues. Relative amounts of PD‐ECGF/TP mRNA were evaluated by reverse transcriptase‐polymerase chain reaction (RT‐PCR) and compared with the level of glycer‐aldehyde‐3‐phosphate dehydrogenase mRNA (used as an internal standard). PD‐ECGF/TP expression was examined by immunohistochemistry in 85 patients who underwent cystectomy for bladder cancer. Serum PD‐ECGF/TP levels were measured in 23 patients using a sandwich‐type enzyme‐linked immunosorbent assay. By RT‐PCR analysis, expression of PD‐ECGF/TP was found to be 7‐fold higher in invasive tumors than in superficial tumors (P<0.01) and 9‐fold higher than in normal bladder (P<0.01). Out of 85 transitional cell carcinoma tissue samples, 69 (81%) were evaluated as PD‐ECGF/TP‐positive by immunohistochemical staining. PD‐ECGF/TP expression correlated significantly with tumor grade (P=0.001), depth of invasion (P=0.012), and lymphatic invasion (P=0.01). No correlation was found between expression of PD‐ECGF/TP and the number of tumors, tumor configuration, lymph node involvement, venous invasion, c‐erbB‐2 expression, or overall survival. We could not detect a significant serum level of PD‐ECGF/TP in any patient. The results suggest that PD‐ECGF/TP might give valuable information for bladder cancer management, though it may not be a good new tumor marker for bladder cancer.