Thymidine phosphorylase expression in invasive carcinoma: correlations with clinicopathologic variables and in vitro chemosensitivity to 5-fluorouracil.

Background: Thymidine phosphorylase (TP) is critical for angiogenic activity, but little information is available on the relationship between TP expression and other Clinicopathologic variables. Furthermore, the relationship between TP and chemosensitivity is still debated.

Materials And Methods: The expression of TP was examined in 116 primary breast carcinomas and in vitro chemosensitivity was assessed in 67 of them by histoculture drug response assay (HDRA) using 5-fluorouracil (5-FU).

Results: Tumor cell TP expression was significantly inversely correlated with histological grade and positively correlated with Bcl-2 expression, but no association with other tumor variables was found. Unexpectedly, TP immunoreactivity was not related to 5-FU chemosensitivity.

Conclusion: The present results suggest that TP is important for remodeling the existing vasculature early in tumor development and intraductal extension, expressions of TP and Bcl-2 are tightly linked and TP status can not generally predict chemotherapeutic sensitivity for 5-FU as a single molecular marker.