cyclophosphamide + docetaxel + epirubicin + metformin

This is a combination regimen consisting of four drugs—cyclophosphamide, docetaxel, epirubicin, and metformin. Cyclophosphamide is an alkylating agent that interferes with DNA replication and RNA transcription, leading to cell death. Docetaxel is a taxane-class chemotherapeutic that stabilizes microtubules and inhibits their depolymerization, thereby blocking cell division. Epirubicin is an anthracycline antibiotic that intercalates into DNA and inhibits topoisomerase II activity, resulting in inhibition of DNA synthesis and function. Metformin is a biguanide antidiabetic drug with emerging evidence for anti-cancer properties; it acts primarily by activating AMP-activated protein kinase (AMPK), inhibiting mTOR signaling pathways, reducing insulin resistance, lowering circulating insulin/IGF-1 levels, and exerting direct cytostatic effects on tumor cells[6][8][10]. This combination has been explored in clinical research settings for the treatment of breast cancer due to the established efficacy of the chemotherapy agents in various regimens (notably TC or TEC protocols) as well as the potential anti-tumor benefits of metformin.