Genomic profiling of cell-free DNA in blood and bone marrow of prostate cancer patients

Copy number variations in primary tumor, serum and lymph node metastasis of bladder cancer patients treated with radical cystectomy

The aim of the present study was to analyze copy number variations (CNV) of multiple oncogenes and tumor suppressor genes in genomic DNA from primary tumor tissue, lymph node metastasis and cell-free DNA (cfDNA) from serum of 72 urothelial carcinoma of bladder (UCB) patients treated with radical cystectomy (RC), using multiplex ligation-dependent probe amplification (MLPA). We hypothesized that primary tumor and lymph node metastasis show similar CNV profiles, and CNV are more present in lymph node metastasis compared to primary tumor tissue. Samples from 43 (59.7%) patients could be analyzed. In total, 35 (83%), 26 (68%) and 8 (42%) patients had CNV in primary tumor, serum and lymph node metastasis, respectively. MYC, CCND1, ERBB2 and CCNE1 displayed the most frequent amplifications. In particular, CNV in ERBB2 was associated with aggressive tumor characteristics. CNV in both ERBB2 and TOP2A were risk factors for disease recurrence. The current findings show that CNV are present in various oncogenes and tumor suppressor genes in genomic DNA from primary tumor, lymph node metastasis and cfDNA from serum. CNV were more present in genomic DNA from primary tumor tissue compared to cfDNA from serum and genomic DNA from lymph node metastasis. Patients with CNV in ERBB2 and TOP2A are at increased risk for disease recurrence following RC. Further studies are necessary to validate, whether these genes may represent promising candidates for targeted-therapy.

Liquid biopsy with cell free DNA: new horizons for prostate cancer

Although prostate cancer (PCa) is one of the most common tumors in European males, the only minimally invasive diagnostic tool in PCa setup is the determination of PSA in serum. Cell-free DNA (cfDNA) has been demonstrated to be helpful for PCa diagnosis but has not yet been integrated into the clinical setting. This review aims to provide a systematic update of cfDNA and its fragmentation patterns in PCa reported in literature published over the last twenty years. Due to the high variability of the scientific methods adopted and a lack of standardized median cfDNA levels, results fluctuate across different studies. These differences may be due to the cfDNA source, the quantification method, or the fragmentation pattern. Blood plasma is the most frequently analyzed biological fluid, but seminal plasma has been reported to contain higher cfDNA concentration due to its vicinity to the tumor origin. CfDNA has been shown to be composed of single-stranded (ssDNA) and double-stranded DNA (dsDNA), so the total cfDNA concentration should be preferred as it corresponds best to the tumor mass. Fluorometry and capillary electrophoresis (CE) may be quick and cost-effective tools for cfDNA assessment in a clinical setting. The greatest future challenge is the elaboration of common guidelines and standardized procedures for diagnostic laboratories performing cfDNA analysis. A multiparametric approach combining the analysis of total cfDNA (both ssDNA and dsDNA), cfDNA fragment length, and specific genetic mutations (ctDNA assessment) is required for optimal future applications of liquid biopsy.

GSTP1 methylation in cancer: a liquid biopsy biomarker?

The coding region of GSTP1 gene is preceded by a large CpG-rich region that is frequently affected by methylation. In many cancer types, GSTP1 is affected by hypermethylation and, as a consequence, it has a low expression. The aim of this review is to give an overview on GSTP1 methylation studies with a special focus on liquid biopsy, thus to summarize methods, results, sample types, different diseases, to have a complete information regarding this promising epigenetic biomarker. We used all the most valuable scientific search engines (PubMed, Medline, Scopus and Web of Science) searching the following keywords: GSTP1, methylation, cancer, urine, serum, plasma and blood. GSTP1 is a largely investigated tissue biomarker in several malignancies such as prostate, breast, lung and hepatocellular carcinoma with good performances especially for diagnostic purposes. As a liquid biopsy biomarker, it has been mainly investigated in prostate cancer (PCa) where it showed a high specificity but a low sensitivity; thus, it is recommended in combination with other biomarkers. Despite the large number of published papers and the promising results, GSTP1 has not yet entered the clinical practice even for PCa diagnosis. For this reason, further large and prospective studies are needed to validate this assay.

Cell-free DNA release under psychosocial and physical stress conditions

The understanding of mechanisms linking psychological stress to disease risk depend on reliable stress biomarkers. Circulating cell-free DNA (cfDNA) has emerged as a potential biomarker of cellular stress, aging, inflammatory processes, and cell death. Recent studies indicated that psychosocial stress and physical exercise might also influence its release. We compared the effects of acute psychosocial and physical exercise stress on cfDNA release by exposing 20 young, healthy men to both an acute psychosocial laboratory stressor and an acute physical exercise stressor. Venous blood and saliva samples were collected before and after stress exposure. Cell-free DNA was extracted from plasma and quantified by qPCR. Furthermore, cfDNA fragment length was analyzed and cfDNA methylation patterns were assayed across time. In addition, release of stress hormones and subjective stress responses were measured. Results showed a twofold increase of cfDNA after TSST and fivefold increase after exhaustive treadmill exercise, with an overabundance of shorter cfDNA fragments after physical exhaustion. Interestingly, cell-free mitochondrial DNA showed similar increase after both stress paradigms. Furthermore, cfDNA methylation signatures-used here as a marker for diverse cellular origin-were significantly different post stress tests. While DNA methylation decreased immediately after psychosocial stress, it increased after physical stress, suggesting different cellular sources of active DNA release. In summary, our results suggest stimulus and cell-specific regulation of cfDNA release. Whereas the functional role of stress-associated cfDNA release remains elusive, it might serve as a valuable biomarker in molecular stress research as a part of the psychophysiological stress response.

Identification of open chromosomal regions and key genes in prostate cancer via integrated analysis of DNase‑seq and RNA‑seq data

Prostate cancer is a type of adenocarcinoma arising from the peripheral zone of the prostate gland, and metastasized prostate cancer is incurable with the current available therapies. The present study aimed to identify open chromosomal regions and differentially expressed genes (DEGs) associated with prostate cancer development. The DNase sequencing data (GSE33216) and RNA sequencing data (GSE22260) were downloaded from the Gene Expression Omnibus database. DNase I hypersensitive sites were detected and analyzed. Subsequently, DEGs were identified and their potential functions were enriched. Finally, upstream regulatory elements of DEGs were predicted. In LNCaP cells, following androgen receptor activation, 244 upregulated and 486 downregulated open chromosomal regions were identified. However, only 1% of the open chromosomal regions were dynamically altered. The 41 genes with upregulated open chromosomal signals within their promoter regions were primarily enriched in biological processes. Additionally, 211 upregulated and 150 downregulated DEGs were identified in prostate cancer, including eight transcription factors (TFs). Finally, nine regulatory elements associated with prostate cancer were predicted. In particular, inhibitor of DNA binding 1 HLH protein (ID1) was the only significantly upregulated TF which exhibited motif enrichment in the promoter regions of upregulated genes. CCCTC‑binding factor (CTCF) and ELK1 ETS transcription factor (ELK1), enriched in the open promoter regions of downregulated genes, were potential upstream regulatory elements. Furthermore, reverse transcription‑quantitative polymerase chain reaction analysis confirmed that ID1 expression was significantly upregulated in LNCaP cells and 5α‑dihydrotestosterone (DHT)‑treated LNCaP cells compared with that in BPH1 cells, while CTCF and ELK1 expression was significantly downregulated in LNCaP cells and DHT‑treated LNCaP cells. In conclusion, ID1, CTCF and ELK1 may be associated with prostate cancer, and may be potential therapeutic targets for the treatment of this disease.

Meta-analysis of CDKN2A methylation to find its role in prostate cancer development and progression, and also to find the effect of CDKN2A expression on disease-free survival (PRISMA)

BACKGROUND

Reduction of cyclin-dependent kinase inhibitor 2A (CDKN2A) (p16 and p14) expression through DNA methylation has been reported in prostate cancer (PCa). This meta-analysis was conducted to assess the difference of p16 and p14 methylation between PCa and different histological types of nonmalignant controls and the correlation of p16 or p14 methylation with clinicopathological features of PCa.

METHODS

According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement criteria, articles were searched in PubMed, Embase, EBSCO, Wanfang, and CNKI databases. The strength of correlation was calculated by the pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs). Trial sequential analysis (TSA) was used to estimate the required population information for significant results.

RESULTS

A total of 20 studies published from 1997 to 2017 were identified in this meta-analysis, including 1140 PCa patients and 530 cases without cancer. Only p16 methylation in PCa was significantly higher than in benign prostatic lesions (OR = 4.72, P = .011), but had a similar level in PCa and adjacent tissues or high-grade prostatic intraepithelial neoplasias (HGPIN). TSA revealed that this analysis on p16 methylation is a false positive result in cancer versus benign prostatic lesions (the estimated required information size of 5116 participants). p16 methylation was not correlated with PCa in the urine and blood. Besides, p16 methylation was not linked to clinical stage, prostate-specific antigen (PSA) level, and Gleason score (GS) of patients with PCa. p14 methylation was not correlated with PCa in tissue and urine samples. No correlation was observed between p14 methylation and clinical stage or GS. CDKN2A mutation and copy number alteration were not associated with prognosis of PCa in overall survival and disease-free survival. CDKN2A expression was not correlated with the prognosis of PCa in overall survival (492 cases) (P > .1), while CDKN2A expression was significantly associated with a poor disease-free survival (P < .01).

CONCLUSION

CDKN2A methylation may not be significantly associated with the development, progression of PCa. Although CDKN2A expression had an unfavorable prognosis in disease-free survival. More studies are needed to confirm our results.

Copy number variations of circulating, cell-free DNA in urothelial carcinoma of the bladder patients treated with radical cystectomy: a prospective study

The aim of the present study was to establish a rapid profiling method using multiplex ligation-dependent probe amplification (MLPA) and characterize copy number variations (CNV) in circulating, cell-free DNA (cfDNA) in 85 urothelial carcinoma of the bladder (UCB) patients treated with radical cystectomy (RC). MLPA was tested for the use of cfDNA extracted from serum and plasma by various commercial extraction kits. Eighteen probes served as reference to control denaturation, ligation and amplification efficiency. MLPA was exclusively suitable for cfDNA extracted from serum. Serum from 72 patients (84.7%) could be analyzed. Thirty-five patients (48.6%) had presence of CNV in cfDNA. The median CNV count in patients with presence of CNV was 2. Predominantly, CNV were located in the genes CDH1, ZFHX3, RIPK2 and PTEN in 15 patients (20.8%), 12 patients (16.7%), 9 patients (12.5%) and 7 patients (9.7%), respectively. CNV in TSG1, RAD21, KIAA0196, ANXA7 and TMPRSS2 were associated with presence of variant UCB histology (p = 0.029, 0.029, 0.029, 0.029, 0.043, respectively). Furthermore, CNV in miR-15a, CDH1 and ZFHX3 were associated with presence of incidental prostate cancer (p = 0.023, 0.003, 0.025, respectively). Patients with CNV in KLF5, ZFHX3 and CDH1 had reduced cancer-specific survival, compared to patients without CNV in these genes (pairwise p = 0.028, 0.026, 0.044, respectively). MLPA represents an efficient method for the detection of CNV among numerous genes on various chromosomal regions. CNV in specific genes seem to be associated with aggressive UCB biologic features and presence of incidental prostate cancer, and may have a negative impact on cancer-specific survival.

Multiplexed methylation profiles of tumor suppressor genes and clinical outcome in oligodendroglial tumors

Aberrant methylation has been associated with transcriptional inactivation of tumor‐related genes in a wide spectrum of human neoplasms. The influence of DNA methylation in oligodendroglial tumors is not fully understood. Genomic DNA was isolated from 61 oligodendroglial tumors for analysis of methylation using methylation‐specific multiplex ligation‐dependent probe amplification assay (MS‐MLPA). We correlated methylation status with clinicopathological findings and outcome. The genes found to be most frequently methylated in oligodendroglial tumors were RASSF1A (80.3%), CASP8 (70.5%), and CDKN2A (52.5%). Kaplan–Meier survival curve analysis demonstrated longer duration of progression‐free survival in patients with 19q loss, aged less than 38 years, and with a proliferative index of less than 5%. Methylation of the ESR1 promoter is significantly associated with shorter duration of overall survival and progression‐free survival, and that methylation of IGSF4 and RASSF1A is significantly associated with shorter duration of progression‐free survival. However, none of the methylation status of ESR1, IGSF4, and RASSF1A was of prognostic value for survival in a multivariate Cox model. A number of novel and interesting epigenetic alterations were identified in this study. The findings highlight the importance of methylation profiles in oligodendroglial tumors and their possible involvement in tumorigenesis.

Regulation of cancer metastasis by cell-free miRNAs

MicroRNAs (miRNAs) are integral molecules in the regulation of numerous physiological cellular processes that have emerged as critical players in cancer initiation and metastatic progression, both by promoting and suppressing metastasis. Recently, cell-free miRNAs shed from cancer cells into circulation have been reported in cancer patients, raising hope for development of novel biomarkers that can be routinely measured in easily accessible samples. In fact, establishing miRNA expression in the circulation likely has advantages over determination in primary tumor tissue, further augmenting the potential applications of miRNA detection in oncological practice. In addition, secretion of miRNAs impacting distant cell signaling or promoting the formation of a niche that sustains a distant tumor microenvironment allows for new treatment approaches to thwart cancer progression.

Aberrantly hypermethylated Homeobox A2 derepresses metalloproteinase-9 through TBP and promotes invasion in Nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is notorious for its high invasiveness and metastatic ability. In this study, we identified a differential hypermethylated transcription repressor, Homeobox A2 (HOXA2), which may render NPC cells invasive and metastatic. Aberrant hypermethylation of HOXA2 led to low RNA expression in NPC tumors and cells. Addition of methylation inhibitor 5'Aza restored HOXA2 RNA expression in NPC cells. Methylated HOXA2 promoter reduces the binding affinity of the transcriptional co-activator p300, causing transcriptional repression of HOXA2. In NPC cells, re-expression of ectopic HOXA2 was correlated with decreased invasive ability and reduced metalloproteinase MMP-9 RNA and protein expression. Promoter, ChIP and DNA-pull down assays indicated that HOXA2 competes with the transcription activator, TATA-box binding protein (TBP) for a recognition sequence near the MMP-9 transcription start site, and suppresses MMP-9 transcription. Thus, HOXA2 acts as a suppressor or TBP-antagonist to inhibit MMP-9 expression; while methylation-mediated inactivation of HOXA2 in NPC derepresses MMP-9 production and increases invasion of NPC cells. In NPC plasma samples, increased plasma EBV copy number was correlated with increased in cell-free HOXA2 hypermethylation and elevated MMP-9 levels. Plasma EBV DNA and methylated cell-free HOXA2 can be used as biomarkers for monitoring NPC treatment.

Challenges for the application of DNA methylation biomarkers in molecular diagnostic testing for cancer

Aberrant DNA methylation is ubiquitous in human cancer and has been shown to occur early during carcinogenesis, thus providing attractive potential biomarkers for the early detection of cancer. The introduction of genome-wide DNA methylation analysis comparing tumor and nonmalignant tissues resulted in the discovery of many regions that undergo aberrant methylation during carcinogenesis. Those regions can potentially be used as biomarkers for cancer detection. However, a biomarker will be useful for screening or early detection of cancer only if it can be detected in a noninvasive or minimally invasive fashion without tissue biopsy. The authors discuss the challenges in translating DNA methylation biomarkers to cancer diagnosis - including obstacles in assay development, tissue-specific methylation load on tumor suppressor genes, detecting markers with sufficient sensitivity and specificity in the periphery, and ways in which these obstacles can be overcome.

APC gene hypermethylation and prostate cancer: a systematic review and meta-analysis

Prostate cancer (PCa) is a worldwide disease that affects a large number of males. Although prostate-specific antigen (PSA) screening is used, the specificity is limited. This study analyzes the sensitivity and specificity of adenomatous polyposis coli (APC) methylation for PCa detection in body fluids and tissues. Combining search results from PubMed and Embase, 19 studies were included, 5 involving body fluids and 14 involving prostate tissue, with 2344 subjects. In body fluid subgroups, the pooled sensitivity and specificity was 0.53 (95% confidence interval (CI): 0.28-0.78) and 0.92 (95% CI: 0.86-0.95), respectively. From tissue studies, the results presented as 0.84 (95% CI: 0.70-0.92) and 0.91 (95% CI: 0.77-0.97). To confirm the results, we conducted a further analysis by removing studies which introduced high heterogeneity due to the type of cases and controls. The same degree of sensitivity and specificity was presented in two subgroups (urine: sensitivity 0.46, 95% CI: 0.39-0.53; specificity 0.87, 95% CI: 0.64-0.96; tissue: sensitivity 0.87, 95% CI: 0.72-0.94; specificity 0.89, 95% CI: 0.68-0.97). In addition, analysis of the interaction between APC methylation and PCa showed strong association in the whole data set (odds ratio (OR)=24.91, 95% CI: 12.86-48.24, I(2)=72.5%). Pooling the same two main subgroups (tissue/fluid) gave a pooled OR of 33.54 (95% CI: 14.88-75.59; I(2)=70.7%) and 8.20 (95% CI: 2.84-23.74, I(2)=64.2%), respectively. From this study, the results suggest that APC promoter methylation may be the potential testing for PCa diagnosis and provide a new viewpoint in the treatment of PCa.

Diagnostic utility of MS-MLPA in DNA methylation profiling of adenocarcinomas and neuroendocrine carcinomas of the colon-rectum

Methylation-specific multiple ligation-dependent probe amplification (MS-MLPA) is a fast, new, inexpensive method that has rarely been exploited in DNA methylation profiling of colorectal cancers (CRCs). The aim of this study was to test the diagnostic utility of MS-MLPA to evaluate the methylation status of 34 genes in normal colonic mucosa samples and in a well-characterized series of 83 adenocarcinomas and 21 neuroendocrine carcinomas of colon-rectum. Two commercial MS-MLPA kits (SALSA MS-MLPA ME001-C1 Tumor suppressor-1 Kit and SALSA MS-MLPA ME002-B1 Tumor suppressor-2 Kit) were used to perform promoter methylation analysis on formalin-fixed and paraffin-embedded tissues. MS-MLPA analysis was validated by bisulfite pyrosequencing, bisulfite cycle sequencing, and methylation-specific PCR. MS-MLPA analysis identified a subset of 27 CRCs (26 % of cases) showing high levels of gene methylation involving a mean percentage of 34 % of the promoters examined. These tumors exhibited all the main clinicopathological and genetic features described for CRCs with CpG island Methylator Phenotype-High. High levels of methylation were observed with similar frequency in adenocarcinomas and in neuroendocrine carcinomas (25 % versus 29 %, respectively), but different methylation profiles were observed in the two tumor types. In both groups, tumors with microsatellite instability and widespread methylation represented a homogeneous clinicopathological entity. MS-MLPA assay is an easy and reliable system for epigenetic characterization of tumor tissues and leads to a rapid identification of CRCs with the highest levels of gene methylation. Aberrant gene methylation is a common abnormality in CRC initiation and may be observed in tumors with very different genetic and clinicopathological profiles.

Genomic deletion of PTEN is associated with tumor progression and early PSA recurrence in ERG fusion-positive and fusion-negative prostate cancer

The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene is often altered in prostate cancer. To determine the prevalence and clinical significance of the different mechanisms of PTEN inactivation, we analyzed PTEN deletions in TMAs containing 4699 hormone-naïve and 57 hormone-refractory prostate cancers using fluorescence in situ hybridization analysis. PTEN mutations and methylation were analyzed in subsets of 149 and 34 tumors, respectively. PTEN deletions were present in 20.2% (458/2266) of prostate cancers, including 8.1% heterozygous and 12.1% homozygous deletions, and were linked to advanced tumor stage (P < 0.0001), high Gleason grade (P < 0.0001), presence of lymph node metastasis (P = 0.0002), hormone-refractory disease (P < 0.0001), presence of ERG gene fusion (P < 0.0001), and nuclear p53 accumulation (P < 0.0001). PTEN deletions were also associated with early prostate-specific antigen recurrence in univariate (P < 0.0001) and multivariate (P = 0.0158) analyses. The prognostic impact of PTEN deletion was seen in both ERG fusion-positive and ERG fusion-negative tumors. PTEN mutations were found in 4 (12.9%) of 31 cancers with heterozygous PTEN deletions but in only 1 (2%) of 59 cancers without PTEN deletion (P = 0.027). Aberrant PTEN promoter methylation was not detected in 34 tumors. The results of this study demonstrate that biallelic PTEN inactivation, by either homozygous deletion or deletion of one allele and mutation of the other, occurs in most PTEN-defective cancers and characterizes a particularly aggressive subset of metastatic and hormone-refractory prostate cancers.

Epigenetic markers of prostate cancer in plasma circulating DNA

Epigenetic differences are a common feature of many diseases, including cancer, and disease-associated changes have even been detected in bodily fluids. DNA modification studies in circulating DNA (cirDNA) may lead to the development of specific non-invasive biomarkers. To test this hypothesis, we investigated cirDNA modifications in prostate cancer patients with locally confined disease (n = 19), in patients with benign prostate hyperplasias (n = 20) and in men without any known prostate disease (n = 20). This initial discovery screen identified 39 disease-associated changes in cirDNA modification, and seven of these were validated using the sodium bisulfite-based mapping of modified cytosines in both the discovery cohort and an independent 38-patient validation cohort. In particular, we showed that the DNA modification of regions adjacent to the gene encoding ring finger protein 219 distinguished prostate cancer from benign hyperplasias with good sensitivity (61%) and specificity (71%). We also showed that repetitive sequences detected in this study were meaningful, as they indicated a highly statistically significant loss of DNA at the pericentromeric region of chromosome 10 in prostate cancer patients (p = 1.8 × 10(-6)). Based on these strong univariate results, we applied machine-learning techniques to develop a multi-locus biomarker that correctly distinguished prostate cancer samples from unaffected controls with 72% accuracy. Lastly, we used systems biology techniques to integrate our data with publicly available DNA modification and transcriptomic data from primary prostate tumors, thereby prioritizing genes for further studies. These data suggest that cirDNA epigenomics are promising source for non-invasive biomarkers.

DNA methylation testing and marker validation using PCR: diagnostic applications

DNA methylation provides a fundamental epigenetic mechanism to establish and promote cell-specific gene-expression patterns, which are inherited by subsequent cell generations. Thus, the epigenome determines the differentiation into a cell lineage but can also program cells to become abnormal or malignant. In humans, different germline and somatic diseases have been linked to faulty DNA methylation. In this article, we will discuss the available PCR-based technologies to assess differences in DNA methylation levels mainly affecting 5-methylcytosine in the CpG dinucleotide context in hereditary syndromal and somatic pathological conditions. We will discuss some of the current diagnostic applications and provide an outlook on how DNA methylation-based biomarkers might provide novel tools for diagnosis, prognosis or patient stratification for diseases such as cancer.

Modified PNA-PCR method: a convenient and accurate method to screen plasma KRAS mutations of cancer patients

KRAS mutations are proved to confer dramatic resistance to EGFR target therapy of cancer patients. The aim of this study was to establish a convenient and accurate method to screen plasma KRAS mutations of cancer patients since tumor specimens were not always available in clinical practice. A modified PNA-PCR method was established and evaluated in plasma of 19 pancreatic cancer patients. Our results showed that the modified PNA-PCR assay was a sensitive (87.5%, 14/16) and accurate (92.9%, 13/14) method to screen plasma KRAS mutations of pancreatic cancer patients and there was a high consistency of KRAS mutation status between plasma samples and tumor specimens. The modified protocol could not only screen plasma KRAS mutations rapidly and accurately but also had potential to quantify KRAS mutant DNA to predict treatment response of cancer patients and monitor disease progression. It's should be indicated that this modified assay was only confirmed in the pancreatic cancer patients in this study and need to be verified in other cancer patients.

DNA methylation in promoter region as biomarkers in prostate cancer

The prostate gland is the most common site of cancer and the second leading cause of cancer death in American men. Recent emerging molecular biological technologies help us to know that epigenetic alterations such as DNA methylation within the regulatory (promoter) regions of genes are associated with transcriptional silencing in cancer. Promoter hypermethylation of critical pathway genes could be potential biomarkers and therapeutic targets for prostate cancer. In this chapter, we updated current information on methylated genes associated with the development and progression of prostate cancer. Over 40 genes have been investigated for methylation in promoter region in prostate cancer. These methylated genes are involved in critical pathways, such as DNA repair, metabolism, and invasion/metastasis. The role of hypermethylated genes in regulation of critical pathways in prostate cancer is discussed. These findings may provide new information of the pathogenesis, the exciting potential to be predictive and to provide personalized treatment of prostate cancer. Indeed, some epigenetic alterations in prostate tumors are being translated into clinical practice for therapeutic use.