In contrast, SMAD4 KD had no effect on DOX and ETOP sensitivity in the presence of rTGF-β1 (average IC50 of 417.6 ± 16.9 nM for DOX and 688.3 ± 84.4 nM for ETOP), whereas NF-κB p65 KD entirely restored the sensitivity of rTGF-β1-treated NB cells (average of 125.6 ± 40.1 nM for DOX and 268.7 ± 69.3 nM for ETOP). Here, SMAD4 is linked to neuroblastoma.