Relationship between thymidine phosphorylase expression and clinical effects of capecitabine: a preliminary study

Objective To evaluate the relationship between thymidine phosphorylase(TP) expression in tumor cells and clinical effects of capecitabine.Methods 33 cases of malignant tumors,including 12 breast cancer and 21 colorectal cancer,were all treated by capecitabine,and clinical evaluations were conducted.Thymidine phosphorylase expression was detected in the tumor cells of these 33 patients before treatment with an immunohistochemical method.The relationship was compared between the effects and the expression.Results TP positive rates in breast cancer patients were 83.3%(10/12),and 57.2%(12/21) in colorectal cancer patients.The total tumor control rates(TCRs) for all patients with breast cancer and colorectal cancer treated by capecitabine were 63.6%(21/33).In the TP positive patients TCRs were 81.8%(18/22),whereas in TP negative patients TCRs were 27.3%(3/11),and the difference had statistical significance(P0.01).Conclusion For breast and colorectal cancers,patients with TP positive expression in tumor cells seem more sensitive to the treatment of capecitabine.This pilot study provides evidence to prognosticate capecitabine effects by detecting TP expression.