NFKB1 and neuroblastoma: In order to examine if the cell growth inhibition in neuroblastoma mediated by topotecan can be synergized with NF-κB pathway inhibition, we tested a specific NF-κB inhibitor, NSC 676914 [19] and a FDA approved proteasome inhibitor which also inhibits the NF-κB pathway, bortezomib, in combination with topotecan.