Occurrence of hematogenous metastasis and serum levels of thymidine phosphorylase in colorectal cancer

Thymidine phosphorylase (dThdPase) is known to promote the development of new blood vessels. Increased dThdPase expression in solid tumors has been shown to correlate with tumor growth, invasion and metastasis. In the present study, we measured dThdPase levels in the tumor tissue and in the serum from the tumor drainage and peripheral venous blood obtained from patients with resectable colorectal cancer. Serum dThdPase levels, measured by a modified ELISA method, were significantly higher in patients with hematogenous metastasis. In the tumor tissue specimens, no significant difference was observed between patients with or without hematogenous metastasis. These results suggest that the serum dThdPase levels are a novel marker to predict occurrence of hematogenous metastasis in patients with resectable colorectal cancer.