This silencing, mediated by hypermethylation of GSTP1 transcriptional regulatory sequences, has been consistently detected in more than 90% of PCa cases [3, 4], and this specificity of GSTP1 promoter methylation measured in body fluids (plasma, serum, and urine) suggests a potential screening measurement for prostate cancer diagnosis [5]. The gene discussed is GSTP1; the disease is prostate cancer.