Our study represents the first to demonstrate a significant association between PRS and BPH within the Han Chinese population. Through the analysis of data gathered from the TCVGH-TPMI cohort, we discovered that PRS serves as a reliable predictor of BPH incidence, as well as other clinical parameters, including prostate volume, response to 5ARI medications, and the future risk of requiring TURP.
As BPH is a prevalent condition among elderly men, identifying individuals at a higher risk of developing it can assist with early intervention and management. The heritability of BPH and male lower urinary tract symptoms in twins has been estimated to range from 20–83% across various cohorts, strongly indicating that genetic factors play a significant role in the development of BPH 5,25,26.
Numerous genes have been shown to be associated with the development of BPH. Among these genes, steroid 5α-reductase 1 (SRD5A1) and steroid 5α-reductase 2 (SRD5A2) encode 5α-reductase type 1 and type 2, respectively, which are involved in testosterone metabolism and have been associated with an increased risk of prostatic hyperplasia 27,28. SRD5A2 is abundantly expressed in the male reproductive system, where it catalyzes the conversion of testosterone to dihydrotestosterone (DHT) 29. A decrease in the expression of SRD5A2 has been associated with underdeveloped and atypical genitalia, while an increase in its expression has been linked to excessive DHT production and an increased risk of BPH 30,31. 5ARIs, such as finasteride and dutasteride, primarily target SRD5A2 and reduce the levels of DHT, thereby indicating their effectiveness in treating BPH 31.
The androgen receptor (AR) signaling pathway has been established as a key contributor to BPH development. Increased AR expression in stromal cells can modify the interaction between epithelial and stromal cells, making the prostate more sensitive to androgen and resulting in hyperplastic growth 32. Blocking or decreasing AR signaling pathway expression could decrease prostate volume and relieve lower urinary tract symptoms 32–34. Specific AR gene polymorphisms, such as SNP rs6152 in the first exon of the AR gene, have been associated with AR expression and the development of androgenetic alopecia and BPH 35. Genomic studies have suggested that FOXA1 regulates the expression of AR and that deletion of FOXA1 in the luminal epithelium of adult mice causes prostatic hyperplasia 36,37. Additionally, NFIB has been found to interact with FOXA1 as a cofactor in regulating AR target gene expression, and loss of NFIB induces prostatic hyperplasia in a mouse model 38. Although the precise mechanism by which these transcription factors contribute to the pathogenesis of BPH remains unclear, various potential genes have been identified to exhibit association with the development of BPH through different etiologies.
The PRS, which is based on multiple genetic markers associated with BPH, can provide a comprehensive risk assessment that takes into account the genetic predisposition of an individual 15. The positive correlation between PRS and BPH incidence suggests that individuals with higher PRS may have a higher risk of developing BPH, and close monitoring and appropriate interventions should be considered in this population.
Gudmundsson et al. provided initial evidence for a positive association between PRS and BPH. Their study utilized data from the Icelandic BPH/LUTS dataset and the UK Biobank dataset, which included a total of 20,621 BPH patients and 280,541 controls of European ancestry. Through genome-wide analysis, the researchers identified 23 variants at 14 loci that were significantly associated with BPH development. Further analysis revealed a strong correlation between PRS and elevated prostate-specific antigen (PSA) levels, as well as an increased risk of BPH development 19. Glaser et al. utilized genome-wide data from the UK Biobank to investigate the genetic relationship between BPH and prostate cancer 39. They found that the two conditions share common inherited genetics. In addition to the study by Conti et al., which identified 239 risk SNPs for prostate cancer, Glaser et al. identified 15 risk SNPs for BPH development, and 49 of the identified SNPs were significantly associated with the risk of the other disease 39,40. Furthermore, the PRS for BPH was significantly associated with prostate cancer risk, and vice versa 39. This suggests that PRS could serve as a comprehensive risk assessment tool for predicting the development of both BPH and prostate cancer. In summary, genetics play a significant role in the occurrence of BPH, and PRS can provide valuable insights for disease prediction.
Our research findings demonstrate a positive correlation between PRS and susceptibility to BPH. Notably, our study deviates from previous literature that has predominantly focused on individuals of European ancestry, as we have specifically analyzed the Han Chinese population. Additionally, patients with prostate cancer were excluded from analysis to prevent any potential confounding factors. As a single-center cohort study, our research benefits from ample medical record availability. We leveraged this advantage by measuring prostate volume as an outcome and discovered that genome-wide factors not only correlated with disease diagnosis 41,42. To the best of our knowledge, this is the first report of such a correlation in the literature. Furthermore, our findings echo those of Gudmundsson et al., as we also observed an association between PRS and elevated PSA levels 19.
Secondly, our study revealed that a lower PRS score was associated with a more favorable response to 5ARI treatment. 5ARI medications, such as finasteride and dutasteride, work by inhibiting the conversion of testosterone to dihydrotestosterone (DHT), which is a key hormonal factor in the development of BPH 43. 5ARI is known to inhibit the activity of the enzyme 5α-reductase, leading to a decrease in DHT levels, induction of apoptosis in prostate epithelial cells, and a resulting reduction in prostate size by approximately 18–28% 44,45. The main target of 5ARI, SRD5A2, is an integral membrane enzyme involved in steroid metabolism. It catalyzes the conversion of testosterone to DHT 46. Prior research has linked high expression of SRD5A2 to increased prostate volume and metabolic syndromes 27. Additionally, Gu et al. reported 11 tagging SNPs in the SRD5A1 and SRD5A2 genes. Among them, rs523349 and rs9332975 at SRD5A2 were significantly associated with baseline prostate volume, rs166050 at SRD5A1 was associated with the posttreatment change in total prostate volume by 5ARI 47,48. Furthermore, Austin et al. reported that activation of NF-κB and AR variant 7 (AR-V7) could result in increased SRD5A2 expression, leading to in vivo prostate growth resistant to 5ARI treatment 49. Conclusively, the finding that PRS is associated with the response to 5ARI medications suggests that genetic factors may influence the efficacy of these medications. PRS can potentially be used to identify individuals who are more likely to respond to 5ARI medications and those who may require alternative treatment options.
Finally, this study also reveals that PRS can predict the risk of requiring TURP in the future. TURP is a common surgical intervention for BPH that is indicated when conservative treatments fail to provide adequate symptom relief 50,51. The finding that PRS is associated with the risk of requiring TURP suggests that genetic factors may influence the disease progression of BPH and the need for surgical intervention. PRS can potentially be used as a prognostic tool to identify individuals at higher risk of requiring TURP in the future, and appropriate management strategies can be implemented accordingly.
There are several limitations to this study that should be acknowledged. Firstly, the PRS is based on genetic markers that have been identified in previous studies, and the selection of genetic markers may not be comprehensive. Our study was unable to provide a definitive explanation for the specific impact of individual genes on the development of benign prostatic hyperplasia. Further research is needed to identify additional genetic markers that may contribute to the prediction of BPH incidence and related parameters. Secondly, the sample size of this study may be relatively small, and larger studies are needed to validate the findings and establish the clinical utility of PRS in predicting BPH outcomes. Additionally, this study is based on a Taiwanese population, and the findings may not be directly applicable to other ethnic populations. Further studies in diverse populations are warranted to assess the generalizability of the findings.