Surprisingly, SMAD2 KD partially but statistically significantly restored the sensitivity of rTGF-β1-treated NB cells to DOX and ETOP (average IC50 of 275 ± 46.9 nM for DOX and 428.4 ± 39.2 nM for ETOP) (Figs. 4c and, S3B). This evidence concerns the gene SMAD2 and neuroblastoma.