Purpose Benign prostatic hyperplasia (BPH) affects over 50 percent of men by age 60 and is the cause of millions of dollars of healthcare expenditure for treatment of lower urinary tract symptoms (LUTS) and urinary obstruction. Despite the widespread use of medical therapy, there is no universal therapy that treats all men with symptomatic BPH, and at least 30% of patients do not respond to medical management and a subset require surgery. Significant advances have been made in understanding the natural history and development of the prostate, such as elucidating the role of the enzyme 5α reductase Type 2 (5AR2), and advances in genomics and biomarker discovery offer the potential for a more targeted approach to therapy. We review the current understanding of BPH progression as well as key genes and signaling pathways implicated in the process such as 5α reductase. We also explore the potential of biomarker screening and gene-specific therapies as tools to risk stratify BPH patients and identify those with symptomatic or medically resistant forms. Materials and Methods A PubMed® literature search of current and past peer-reviewed literature on prostate development, lower urinary tract symptoms, BPH pathogenesis, targeted therapy, biomarkers, epigenetics, 5AR2 and personalized medicine was performed. An additional Google Scholar™ search was conducted to broaden the scope of the review. Relevant reviews and original research articles were examined as well as their cited references, and a synopsis of original data was generated with the goal of informing the practicing urologist of these advances and their implications. Results BPH is associated with a state of hyperplasia of both the stromal and epithelial compartments, with 5AR2 and androgen signaling playing key roles in development and maintenance of the prostate. Chronic inflammation, multiple growth factor and hormonal signaling pathways, and medical comorbidities play an intricate role in prostate tissue homeostasis as well as its evolution into the clinical state of BPH. Resistance to medical therapy with finasteride may occur through silencing of the 5AR2 gene by DNA methylation, leading to a state in which 30% of adult prostates do not express 5AR2. Novel biomarkers such as single nucleotide polymorshisms may be used to risk stratify patients with symptomatic BPH and identify those at risk of progression or failure of medical therapy. Several inhibitors of the androgen receptor and other signaling pathways have recently been identified which appear to attenuate BPH progression and may offer alternative targets for medical therapy. Conclusions Progressive worsening of LUTS and bladder outlet obstruction secondary to BPH is the result of multiple pathways including androgen receptor signaling, pro-inflammatory cytokines and growth factor signals. New techniques in genomics, proteomics and epigenetics have led to the discovery of aberrant signaling pathways, novel biomarkers, DNA methylation signatures and potential gene-specific targets. As personaliz...

5-α Reductase type 2 (SRD5A2) is a critical enzyme for prostatic development and growth. Inhibition of SRD5A2 by finasteride is used commonly for the management of urinary obstruction caused by benign prostatic hyperplasia. Contrary to common belief, we have found that expression of SRD5A2 is variable and absent in one third of benign adult prostates. In human samples, absent SRD5A2 expression is associated with hypermethylation of the SRD5A2 promoter, and in vitro SRD5A2 promoter activity is suppressed by methylation. We show that methylation of SRD5A2 is regulated by DNA methyltransferase 1, and inflammatory mediators such as tumor necrosis factor α, NF-κB, and IL-6 regulate DNA methyltransferase 1 expression and thereby affect SRD5A2 promoter methylation and gene expression. Furthermore, we show that increasing age in mice and humans is associated with increased methylation of the SRD5A2 promoter and concomitantly decreased protein expression. Artificial induction of inflammation in prostate primary epithelial cells leads to hypermethylation of the SRD5A2 promoter and silencing of SRD5A2, whereas inhibition with tumor necrosis factor α inhibitor reactivates SRD5A2 expression. Therefore, expression of SRD5A2 is not static and ubiquitous in benign adult prostate tissues. Methylation and expression of SRD5A2 may be used as a gene signature to tailor therapies for more effective treatment of prostatic diseases.

Purpose 5α reductase inhibitors (5ARIs) are a main modality of treatment for men suffering from symptomatic benign prostatic hyperplasia (BPH). Over 30% of men do not respond to the therapeutic effects of 5ARIs. We have found that 1/3 of adult prostate samples do not express 5AR2 secondary to epigenetic modifications. We sought to evaluate whether 5AR2 expression in BPH specimens of symptomatic men was linked to methylation of the 5AR2 gene promoter and identify associations with age, obesity, cardiac risk factors, and prostate specific antigen (PSA). Materials and Methods Prostate samples from men undergoing transurethral prostate resection were used. 5AR2 protein expression and gene promoter methylation status were determined by common assays. Clinical variables included age, body mass index (BMI), hypertension, hyperlipidemia, diabetes, PSA, and prostate volume. Univariate and multivariate statistical analyses were performed, followed by stepwise logistic regression modeling. Results BMI and age were significantly correlated with methylation of the 5AR2 gene promoter (p<0.05), whereas prostate volume, PSA, or use of BPH medication were not. Methylation was highly correlated with 5AR protein expression (p<0.0001). In a predictive model, both increasing age and BMI significantly predicted methylation status and protein expression (p<0.01). Conclusions Increasing age and BMI correlate with increased 5AR2 gene promoter methylation and decreased protein expression in men with symptomatic BPH. These results highlight the interplay between age, obesity and gene regulation. Our findings suggest the presence of an individualized epigenetic signature for symptomatic BPH, which may be important for choosing appropriate personalized treatment options.