To test the hypothesis that IL-6 inhibition may represent a preferential target for Pax5-dependent B-ALLs, and to expand our studies to more clinically relevant settings, we first tested whether IL-6 contributes to Pax5-dependent B-ALL maintenance, since IL-6 is a secreted protein, and as such it is amenable to targeting by neutralizing antibodies26 and, moreover, such an antibody treatment has already been shown to be tolerated in humans27. Here, PAX5 is linked to precursor B-cell acute lymphoblastic leukemia.