Subsequent studies have identified more than 40 genes that are targeted by DNA hypermethylation in prostate cancer cells, including RASSF1A (ras association domain family protein 1, isoform A), RARβ2 (retinoic acid receptor β2), p16INK4a, and PTEN (phosphatase and tensin homolog) tumor suppressor genes [11-13]. Here, PTEN is linked to prostate cancer.