G6PD and neoplasm: To investigate if 1,25(OH)2D3’s induction of G6PD expression and activity would hamper such anti-tumor strategies, G6PD was genetically and pharmacologically inhibited in MCF-7 cells using siRNA and DHEA, respectively, in the presence and absence of 1,25(OH)2D3, and cellular survival was assessed by SRB assay.