Prostate cancer is the most prevalent cancer and the second leading cause of cancer death in men. Serum prostate-speciﬁc antigen (PSA) screening is the gold standard biomarker for prostate cancer diagnosis and management. The problem is that the PSA test has poor speciﬁcity. Epigenetic-based biomarkers may provide the next future step in prostate cancer diagnosis and prognosis, especially as genome-wide sequencing and analysis approaches. DNA methylation, posttranslational histone modiﬁcations, the incorporation of histone variants and expression of non-coding RNAs are four major epigenetic markers.
Low levels of cytosine methylation in non-CpG contexts have also been identiﬁed by methylome sequencing in embryonic stem cells, oocytes and brain. 5mCpG promoter hypermethylation is the best-characterised epigenetic alteration in prostate cancer. The global levels of 5hmC have found to be strongly reduced in cancer, including prostate cancer.
Each miRNA can potentially bind and inhibit 200 or more different mRNAs simultaneously, and also each mRNA can be targeted by multiple miRNAs.
One of the main challenge there are limited bioinformatic tools and that our knowledge in the cancer epigenomic landscape needs a deeper understanding. New technologies, such as NGS for global epigenomic analyses and integration with genomic and transcriptomic data, will exponentially expand our understanding of prostate tumorigenesis and will yield more clinically informative epigenetic biomarkers to aid in disease stratiﬁcation.