Abstract
Gamma delta T-cell (γδ T-cell) acute lymphoblastic leukemia(γδ T-ALL) is rare and aggressive, but secondary γδ T-ALL following breast cancer is more rare. Our case presents a patient with breast cancer, received surgical treatment and chemotherapy consisting of epirubicin and cyclophosphamide. Three years later, the patient got secondary γδ T-ALL. The chemotherapeutic agents had a significant effect on the breast cancer patient, who has an increased risk of secondary γδ T-ALL.