Figure 3.

Mechanisms of action of trastuzumab. A) Trastuzumab may cause immune activation by recruiting natural killer (NK) cells, leading to cancer cells lysis. B) Trastuzumab may physically block either human epidermal growth factor receptor 2 (HER2) homodimerization or heterodimerization with other HER family partners. C) Trastuzumab may inhibit the shedding of HER2 extracellular domain, preventing the formation of p95. D) Trastuzumab may reduce the signaling from downstream pathways by the internalization and degradation of HER2.