Although our results have demonstrated that NPTX2 is expressed at low levels in prostate cancer and that 5-AZA-dC can upregulate its levels in DU145 and PC3 cell lines, NPTX2 is relatively highly expressed in the C4-2 cell line and 5-AZA-dC has no regulatory effect on it, indicating that the NPTX2 promoter is not methylated at C4-2, indicating there are more mechanisms to explore in the occurrence and development of prostate cancer. This evidence concerns the gene NPTX2 and prostate cancer.