FCGR2A and neuroblastoma: We observed no ADCC activity of DB or NAXI against neuroblastoma cells with low or no GD2 expression (SHEP-2, SK-N-SH, COG-N-519) at any concentration, suggesting that GD2 surface expression is crucial for antibody-mediated Fcγ receptor (FcγR) activation (Supplemental Figure S2).