ERBB2 and breast cancer: Alterations in the PI3K/AKT signaling pathway have been shown to track consistently with therapy-induced resistance in breast cancer patients, including endocrine-based therapy, chemotherapy and HER2-targeted therapy.36, 37, 38 Recent studies demonstrate that targeting the PI3K/AKT pathway in combination with trastuzumab or tamoxifen is beneficial in trastuzumab-resistant breast cancer or endocrine therapy-resistant breast cancer.38, 39 Hence, we further investigated whether BKM120 could synergize with chemotherapeutic agents commonly used in breast cancer therapy regimens.