ERBB2 and breast cancer: Another preclinical study showed that lapatinib alone or in combination with trastuzumab trastuzumab inhibited HER2 phosphorylation, prevented receptor ubiquitination, and resulted in the accumulation of inactive HER2 at the cell surface of HER2-overexpressing breast cancer cell lines, which led to the subsequent enhancement of ADCC by trastuzumab [66].