In conclusion, our results indicate that ATRA induces activity of the COX-2 promoter and synthesis of COX-2 mRNA and COX-2 protein, resulting in increased PGE2 production in SH-SY5Y human neuroblastoma cells; and that RARs and ERK1/2 were required for these ATRA effects. This evidence concerns the gene MAPK3 and neuroblastoma.