There is evidence that trastuzumab inhibits proliferation and survival of breast cancer cells by mechanisms that include stimulation of antibody-dependent cell-mediated cytotoxicity (ADCC) [22,23], inhibition of angiogenesis [24,25], and enhancement of endocytic degradation of HER2/neu, although the latter finding remains controversial [23]. Here, ERBB2 is linked to breast carcinoma.