Dual-luciferase, nuclear run-on, real-time quantitative RT-PCR, and western blot assays further indicated that stable transfection of Smad4 prevented the NB cells from increased promoter activity and expression levels of HPSE induced by LEF1 over-expression (Supplementary Fig. S4a, Fig. 3f–h). This evidence concerns the gene LEF1 and neuroblastoma.