[Evaluation of 5-fluorouracil-related genes in breast cancer to predict the effect of adjuvant therapy with CMF].

The correlations between mRNA expressions of 5-fluorouracil(5-FU)-related enzymes; thymidylate synthase(TS), dihydropyrimidine dehydrogenase(DPD), thymidine phosphorylase(TP), and orotate phosphoribosyltransferase (OPRT)in breast cancers, along with disease-free survival(DFS), were investigated in 35 patients treated with postoperative adjuvant chemotherapy using cyclophosphamide, methotrexate and 5-fluorouracil(CMF). The patients treated with CMF were divided into two groups, a lower group(L group)and a higher group(H group), according to the median value of the mRNA expression for each enzyme in 220 breast cancer specimens, which were resected between 1996 and 1998 in our institute. 5-year DFS was not significantly different between TS-L and H group(60% and 80%, p=0.38), DPD-L and H group(57.9% and 86.7%, p=0.088), and TP-L and H group(70% and 73.3%, p=0.89), respectively. 5-year DFS in the OPRT-H group(88.9%)was significantly better than that in the OPRT-L group(50%) (p=0.024). In the OPRT-H group, despite the fact that the proportion of patients with lymph node involvement in the CMF group was significantly higher than that in the postoperative adjuvant hormone therapy group, 5-year DFS was not significantly different between the two groups(p=0.10). Our results suggest that OPRT level was the significant predictive marker for DFS in the breast cancer patients treated with postoperative adjuvant chemotherapy using CMF.

Steroid sulfatase in breast carcinoma and change of serum estrogens levels after operation.

Fifty-four breast carcinomas were studied for the expression of steroid sulfatase (STS) by immunohistochemistry. Correlations between the expression of STS and clinical parameters were determined. Concentrations of serum estrone (E1), estrone sulfate (E1S), estradiol (E2) and estradiol sulfate (E2S) in 12 postmenopausal patients with STS positive tumor were measured by radioimmunoassay. Positive expression of STS was obtained in 72% of tumors. The incidence of STS positive tumor was significantly more frequent in postmenopausal patients (p = 0.01). In our postmenopausal patients, serum E1, E1S, E2, E2S and E2S levels in STS high score group were decreased postoperatively, and those in both STS high and low score group were stabilized after operation. Results from this study suggest STS in breast carcinoma may play an important enzyme of the intratumoral estrogen synthesis in postmenopausal women, and it would be interesting that locally produced STS might be closely related to the control of estrogens environment in breast carcinoma.