GSTP1 is involved in the cellular protection system against toxic effects and is especially promising as a biomarker because it is highly specific for prostate cancer (>90%); levels of GSTP1 methylation are associated with different stages of the disease; levels of GSTP1 promoter region methylation can differentiate between prostate cancer and BPH and they are detectable by noninvasive means in body fluids [103–106]. The gene discussed is GSTP1; the disease is Familial prostate cancer.