Fig. 1

The antitumor mechanisms of anti-HER2 monoclonal antibody (taking an example of trastuzumab). a Trastuzumab downregulates HER2 expression by inducing receptor internalization and degradation. b Trastuzumab binding to extracellular subdomain IV of HER2 inhibits the homodimerization of HER2 and blocks downstream PI3K/Akt and Ras/Raf/MAPK pathways. c Trastuzumab plays a role in inhibiting angiogenesis. d Fc fragment of trastuzumab binding to NK cells triggers potent ADCC and secretion of cytokines to kill tumor cell