We performed an upstream regulatory analysis in SEdb to investigate the reason why SMAD9 was highly and specifically expressed in NB, showing that SMAD9 was a specific SEs-targeted gene in NB compared to other cancer types according to SE counts (Figs. 2A and S4A-B), SE rank (Fig. 2B) and SE binding patterns (Fig. 2C). This evidence concerns the gene SMAD9 and neuroblastoma.