ERBB2 and neoplasm: Besides blocking the oncogenic signals of amplified HER2 (PI3K/Akt and Ras/MAPK pathways), inhibiting cell cycle progression, reducing angiogenesis, and preventing the cleavage of the extracellular domain of HER2, trastuzumab mediates its anti-tumor activity by activating ADCC, which relies on effective innate and adaptive immunity [12].