We studied CD70 expression profiles in different cohorts of BCP-ALL samples and evaluated CD70 as immunotherapeutic target using CD70-directed antibodies in vitro, ex vivo and in vivo...Therefore, we further evaluated CD70 as target for directed immunotherapy. Anti-CD70 monoclonal antibodies displayed antibody dependent cell mediated cytotoxicity against primary BCP-ALL cells and cell lines with CD70 expression in vitro....Moreover, we also investigated anti-CD70 activity in a pre-clinical model of manifest ALL and observed a dose-dependent, significant leukemia reduction in treated animals.