ABCB1 and neuroblastoma: We first demonstrated that blocking STAT3 activation by inhibiting IL-6 binding to its receptor with Tocilizumab or blocking JAK2 activation with Ruxolitinib, had no effect on SMAD2 and NF-κB p65 phosphorylation in TGF-β1-treated NB cells (Fig. 5d) but partially restored sensitivity to DOX and ETOP (Figs. 5e and, S4G) and inhibited the expression of BCL-xL but not MDR1 and MRP1 (Fig. 5f).