Thymidine phosphorylase and dihydropyrimidine dehydrogenase expression levels in tumor and normal tissue specimens of T3 human colorectal carcinoma.

Purpose: Thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) are important enzymes related to the metabolism of 5-fluorouracil and its derivatives. We evaluated the association between the clinicopathological factors and these enzymes in patients with T3 colorectal carcinoma.

Methods: The TP and DPD expression levels in 15 patients with T3 colorectal carcinomas were measured in tumor and adjacent normal tissue specimens by enzyme-linked immunosorbent assay.

The transfection of thymidylate synthase antisense suppresses oncogenic properties of a human colon cancer cell line and augments the antitumor effect of fluorouracil.

5-Fluorouracil (5-FU), a fluoropyrimidine analogue, is one of the most commonly used anticancer drugs for the treatment of gastrointestinal malignancies. Some studies reported that the cytotoxicity of fluoropyrimidines is mediated, in large part, by inhibition of the thymidylate synthase (TS), an essential DNA synthetic enzyme. The aim of this study was to determine if antisense TS technology could augment the chemosensitivity of human cancer cells to 5-FU.