Lapatinib is used as a treatment for treatment-naive women with breast cancer, ER+/EGFR+/HER2+ breast cancer patients (now often called "triple positive") and patients who have HER2-positive advanced breast cancer that has progressed after previous treatment with other chemotherapeutic agents, such as anthracycline, taxane-derived drugs, or trastuzumab [26]. This evidence concerns the gene ERBB2 and breast cancer.