An abbreviation for a chemotherapy combination used to treat breast cancer. It includes the drugs doxorubicin hydrochloride (Adriamycin) and cyclophosphamide, followed by treatment with paclitaxel (Taxol) and trastuzumab (Herceptin). Also called AC-T-T, AC-TH regimen, and sequential AC/Taxol-Trastuzumab regimen.