Introduction
breast cancers, breast cancer
CYTOTOXICITY, HER2+ BREAST CANCER, BREAST CANCER
Human epidermal growth factor receptor 2-positive (HER2+) breast cancer accounts for approximately 20% of all breast cancers [Trastuzumab was the first HER2-targeted therapy approved for the treatment of HER2+ breast cancer. Trastuzumab targets a juxtamembrane epitope in subdomain IV of the extracellular portion of the HER2 protein. Once bound, trastuzumab suppresses HER2 intracellular signalling, and trastuzumab’s human IgG1 isotype framework was deliberately designed to elicit antibody-dependent cell-mediated cytotoxicity (ADCC) [Lapatinib is a small molecule tyrosine kinase inhibitor (TKI) that targets EGFR and HER2 and it is approved for use in combination with capecitabine as second-line therapy for metastatic HER2+ breast cancer that is refractory to trastuzumab, or to treat advanced hormone receptor positive HER2+ breast cancer in combination with letrozole [Other clinical trials investigating the combination of trastuzumab and lapatinib in the neo-adjuvant setting have been conducted: CHER-LOB [