RUNX1T1 and neuroblastoma: Even more importantly, the value of BPPB IC50 on HTLA-ER (IC50 = 1.1 μM) HR-NB cells was 538-fold lower than that reported for ETO (IC50 = 592 μM), a clinically approved drug to treat HR-NB cells, which unfortunately develops resistance after only six months of treatment.