SLC39A1 and Familial prostate cancer: An early epigenetic analysis shows that it is the hypermethylation of promoter region of transcription factor activating enhancer-binding protein-2α (AP-2α), a regulator of ZIP1, but not the methylation of ZIP1 promoter, is the mechanism responsible for the downregulation of ZIP1 in DU145 and LNCaP prostate cancer cells [49].