ERBB2 and cancer: To investigate the combined effect of target binding and Fc-mediated FcαRI engagement in a cellular ADCC assay, titrated amounts of the anti-HER2 AlbuAbs were added to freshly isolated human PMNs and HER2-expressing cancer cell lines (Fig. 2C), either expressing high (SK-BR-3, Fig. 2D) or intermediate (MCF-7-HER2, Fig. 2E) HER2 levels on their cell surface (Fig. S3).