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Updated: Aug 19, 2026
Multiomics Analysis of TMEM200A as a Pan-Cancer Biomarker
Published on: September 15, 2023
Prognostic importance of thymidylate synthase expression in early breast cancer
B C Pestalozzi1, H F Peterson, R D Gelber
1National Cancer Institute-Navy Medical Oncology Branch, Division of Clinical Sciences, Bethesda, MD, USA.
Purpose:
To assess the prognostic importance of thymidylate synthase (TS) expression in breast tumors of patients with early-stage breast cancer, and to determine whether the benefit of chemotherapy (CT) is associated with TS expression.
Patients And Methods:
The level of TS expression was evaluated in 210 node-negative and 278 node-positive patients enrolled onto Trial V of the International Breast Cancer Study Group ([IBCSG] formerly the Ludwig Breast Cancer Study Group) with a median follow-up time of 8.5 years. TS expression was assessed using the immunohistochemical method with the monoclonal antibody TS 106 on paraffin-embedded tissue specimens.
Results:
High TS expression was associated with a significantly worse prognosis in node-positive but not in node-negative breast cancer patients. Twenty-seven percent of node-positive patients with high TS expression were disease-free at 10 years, compared with 44% of node-positive patients with low TS expression (P = .03). Forty-one percent of patients with node-positive high-TS-expressing tumors were alive after 10 years, compared with 49% of those with low TS expression (P = .06). The association between TS and disease-free survival (DFS) and overall survival (OS) was independent of other prognostic factors such as tumor size, tumor grade, nodal status, vessel invasion, estrogen receptor (ER)/ progestin receptor (PR) status, c-erb B-2, or Ki-67 expression. In node-positive patients, six cycles of standard adjuvant cyclophosphamide, methotrexate, and fluorouracil ([5-FU] CMF) CT improved DFS and OS compared with one cycle of perioperative CMF therapy. The magnitude of this benefit was greatest in patients whose tumors had high TS expression (P < .01 for DFS; P < .01 for OS). Node-negative patients demonstrated no difference in outcome to CT based on TS expression; however, the power to detect differences was limited by the small number of events in this group.
Conclusion:
In early-stage breast cancer, high TS expression is associated with a significantly worse prognosis in node-positive patients. Node-positive patients with high TS levels demonstrate the most significant improvement in DFS and OS when treated with six cycles of conventional adjuvant CMF therapy.
