Its anti-tumor action interferes with HER2 signaling following binding to the extracellular domain of the receptor through several mechanisms: antibody-dependent cellular cytotoxicity (ADCC), inhibition of the HER2 receptor dimerization, receptor internalization and/or degradation, and inhibition of downstream signaling pathways, i.e., the PI3K-AKT signaling pathway [39]. The gene discussed is ERBB2; the disease is neoplasm.