ERBB2 and breast cancer: For example, release of exosomes from HER2-overexpressing breast cancer cell lines (BT474 and SKBR3) or from HER2-positive breast cancer patient serum could bind to Trastuzumab (a monoclonal antibody therapy that interferes with the HER2 receptor) and lead to an inhibition of the anti-proliferative effects of Trastuzumab on SKBR3 cells.