FCGR3A and neoplasm: Considering the increase in apoptosis observed in the SKBR3 co-cultures upon antibody challenge (Figure 5A), and the proximity between tumor and immune cells in this co-culture (Figure 3E), it is plausible that the CD16 downregulation induced in NK cells by trastuzumab and pertuzumab challenge resulted from NK-mediated ADCC.