methotrexate + fluorouracil + tamoxifen

This is a combination regimen consisting of three drugs—methotrexate, fluorouracil (5-fluorouracil or 5-FU), and tamoxifen—used primarily in the treatment of advanced or metastatic breast cancer. Methotrexate is an antimetabolite that inhibits dihydrofolate reductase, interfering with DNA synthesis and cell replication. Fluorouracil is a pyrimidine analog that inhibits thymidylate synthase, disrupting DNA synthesis. Tamoxifen is a selective estrogen receptor modulator (SERM) that acts as an antagonist on estrogen receptors in breast tissue, inhibiting hormone-driven tumor growth. The combination leverages both cytotoxic chemotherapy and hormonal therapy to target heterogeneous breast tumors with varying estrogen receptor status. Preclinical studies have shown synergistic cytotoxicity when these agents are used together[1][2]. Clinical studies report high response rates and manageable toxicity profiles for this regimen in patients with advanced breast cancer[1].