Promoter hypermethylation leading to epigenetic silencing of GSTP1 gene expression is frequently detected in prostate cancer cells, the most commonly diagnosed type of malignancy among men in Western European countries and the second cause of cancer-related deaths among men worldwide (Brooks et al., 1998; Cairns et al., 2001; Jeronimo et al., 2002; Henrique and Jeronimo, 2004; Dumache et al., 2010; Ferlay et al., 2010). The gene discussed is GSTP1; the disease is prostate cancer.