ESR1 and breast cancer: Imatinib- is used for CML(Chronic Myelogenous Leukemia) and ALL(Acute lymphocytic Leukemia) and other gastrointestinal stromal tumours(GIST).Lapatinib- Used in treatment-naïve, ER+/EGFR+/HER2+ breast cancer patients and patients with HER2-positive advanced breast cancer that has progressed after previous treatment to Trastuzumab, anthracycline and taxane derived drugs.Combinatorial Drug Therapy for Triple Negative Breast Cancer.