SMAD9 and neuroblastoma: We detected MYCN expression in NB cell lines (SK-N-SH, SH-SY5Y, SK-N-BE2, BE(2)-C, IMR-32) at the protein level (Fig. S5A) and SMAD9 and MYCN mRNA expression in NB cell lines, a fibroblast cell line (RPE-1), epithelium-derived cell line (MCF-10) and NB tissues from SCH (Fig. S5B).