PHOX2B and neuroblastoma: Treating MYCN-amplified neuroblastoma cells with ATRA resulted in rapid down-regulation of MYCN expression, loss of H3K27ac chromatin modifications associated with active super-enhancers within the PHOX2B and GATA3 gene loci, and the acquisition of H3K27me3 chromatin silencing modifications of the promoters of these genes, which together lead to decreased expression levels of members of the adrenergic CRC.