Epigenetic markers for molecular detection of prostate cancer

Prostate cancer is a highly prevalent malignancy, which is clinically silent but curable while organ-confined. Because available screening methods show poor sensitivity and specificity, the development of new molecular markers is warranted. Epigenetic alterations, mainly promoter hypermethylation of cancer-related genes, are common events in prostate cancer and might be used as cancer biomarkers. Moreover, the development of quantitative, high-throughput techniques to assess promoter methylation enabled the simultaneous screening of multiple clinical samples. From the numerous cancer-related genes hypermethylated in prostate cancer only a few proved to be strong candidates to become routine biomarkers. This small set of genes includes GSTP1, APC, RARbeta2, Cyclin D2, MDR1, and PTGS2. Single and/or multigene analyses demonstrated the feasibility of detecting early prostate cancer, with high sensitivity and specificity, in body fluids (serum, plasma, urine, and ejaculates) and tissue samples. In addition, quantitative hypermethylation of several genes has been associated with clinicopathologic features of tumor aggressiveness, and also reported as independent prognostic factor for relapse. The identification of age-related methylation at specific loci and the differential frequency of methylation among ethnical groups, also provided interesting data linking methylation and prostate cancer risk. Although large trials are needed to validate these findings, the clinical use of these markers might be envisaged for the near future.