Although past studies have shown that 5-aza-CdR was able to demethylate and re-express GSTP1 in prostate cancer cells [54], [55], [56], our results are the first to demonstrate that GSTP1 methylation and protein status was indicative of 5-aza-CdR treatment efficacy using a daily low-dose treatment regime. The gene discussed is GSTP1; the disease is Familial prostate cancer.