Notably, induction of NK cell ADCC was less pronounced with Trastuzumab as compared to Rituximab, which can be explained by the lower expression levels/molecule counts of HER2/neu compared to CD20 on the cell surface of ALL blasts observed by us and others [41] and is in line with the fact that induction of ADCC by a given antibody correlates with the expression level of its target antigen [42, 43]. This evidence concerns the gene ERBB2 and acute lymphoblastic leukemia.