Clinical significance of intratumoral TS levels and DPD activity in breast cancer

: We evaluated the usefulness of the level of thymidylate synthase(TS)and dihydropyrimidine dehydrogenase(DPD) activity as prognostic factors and indicators for selection of chemotherapy regimens. Between November 1997 and March 1999, fifty-seven patients with stages I - IIIa primary breast cancer were registered. Using recurrence risk categories, they were classified into TAM monotherapy, TAM+oral 5-FU, and TAM+CMF groups(each were standard regimens at the time), and underwent postoperative adjuvant chemotherapy. The relationship between prognosis and the TS level and DPD activity, in addition to conventional risk factors, was examined. The recurrence-free survival time curve showed significant differences when stratified by tumor diameter, ER expression, and TS levels, but not by menopausal status, nodal status, surgical method, p53 expression, DPD activity, or HER2 expression. These results suggest that the TS level is useful as a prognostic factor for breast cancer.