Since the CpG region in the promoter of exon 1c in leukemia cell lines was fully methylated, we hypothesized that hypomethylating agents, zebularine (ZEB) or 5-azacytidine (5AZA), may increase VDR expression, and, in consequence, the activity of VDR as a transcription factor. The gene discussed is VDR; the disease is leukemia.