VDR and neuroblastoma: We have confirmed that 1,25(OH)2D3 positively regulates TH mRNA and protein, and the metabolic product of TH, DA using a VDR‐overexpressing neuroblastoma cell system.(117) Simply increasing VDR expression alone in the absence of 1,25(OH)2D3 is also sufficient to drive undifferentiated cells down a dopaminergic lineage.(135) In addition, we have established that 1,25(OH)2D3 increases VDR regulation of a major metabolic enzyme for DA in the brain, COMT.