CD38 and prostate cancer: To test if CD38 is regulated epigenetically by CpG methylation, we first performed in silico analysis and identified a CpG island in close proximity to the transcriptional start site of CD38. Furthermore, re-analysis of publicly available reduced representation bisulfite sequencing (RRBS) data [57] for the prostate cancer cell line LNCaP demonstrated that dense CpG methylation was present around the transcriptional start site and in the first exon of CD38 (Fig. 3a).