Enhancement of immunohistochemical reactivity for thymidine phosphorylase in breast carcinoma cells after administration of docetaxel as a neoadjuvant chemotherapy in advanced breast cancer patients.

For the purpose of demonstrating possible effects of docetaxel on thymidine phosphorylase (TP) activity in human breast carcinoma, we examined breast carcinoma tissues pre- and post-administration of docetaxel, by an immunohistochemical method using an anti-TP monoclonal antibody. Eight patients with advanced breast carcinoma were initially treated with 3 cycles of 60 mg/m2 of docetaxel once every 3 weeks after incisional biopsy of tumors, and following 3 cycles of docetaxel, they underwent mastectomy with axillary dissection. Grades of immunohistochemical reactivity for TP of carcinoma cells in pre- and post-treatment specimens were compared. Five biopsy specimens (62.5%) were positive for TP. After administration of docetaxel, 6 of 8 cases (75.0%) revealed significant enhancement of reactivity for TP. Increased reactivity was recognized diffusely as well as focally in carcinoma tissues. From these results, we believe that administration of docetaxel to breast cancer patients evokes enhancement of immunohistochemical reactivity for TP in breast carcinoma cells in situ. Furthermore, we consider that docetaxel treatment might improve efficacy of additional doxifluridine and capecitabine therapy.