Role of hormonal genes and risk of prostate cancer: gene-gene interactions in a North Indian population

Systematic review and meta-analysis of candidate gene association studies of benign prostate hyperplasia

BACKGROUND

Benign prostate hyperplasia (BPH) is the most common urological problem in elderly males. Recent studies have reported polymorphism in various metabolic genes in BPH. However, their association with the susceptibility of BPH is still inconsistent. Here, we systematically reviewed and performed a meta-analysis of CYP17, VDR, and ACE genes to determine their precise association with the risk of BPH.

METHODS

A comprehensive literature search for published studies on candidate gene associations involving vitamin D receptor (VDR), angiotensin-converting enzyme (ACE), and CYP17 genes with the risk of BPH was done up to April 2020 in PubMed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar databases. Fixed/random effects models were used to estimate the odd's ratio (OR) and 95% confidence intervals (CIs). Begg's funnel plot was used to assess the potential for publication bias.

RESULTS

We found a total of 23 studies containing 3461 cases and 3833 controls for these gene polymorphisms. A significant association of ACE gene polymorphism was observed under the recessive (II vs. ID + DD) model for BPH susceptibility compared to control subjects (overall OR = 1.67, 95% CI = 1.03-2.73). Similar trends were observed for ACE gene polymorphism in Caucasian (OR = 6.18, 95% CI = 1.38-27.68) and Asian (OR = 1.42, 95% CI = 0.99-2.03) populations under study. No significant association was observed in VDR and CYP17 gene polymorphisms in any dominant or recessive models.

CONCLUSION

Significant OR demonstrated the implication of ACE gene polymorphism in the proliferation of prostate tissue, which in turn is associated with BPH susceptibility. However, prospective studies at large scale and sample size are needed to confirm the current findings.

Polymorphism in the Androgen Biosynthesis Gene (CYP17), a Risk for Prostate Cancer: A Meta-Analysis

Gene polymorphism is one of the few factors that increases the risk of prostate cancer. T to C substitution in the 5’ promoter region of the CYP17 gene is hypothesized to increase the rate of gene transcription, increase androgen production, and thereby increase the risk of prostate cancer. Nevertheless, the inconsistencies originating from studies on CYP17 polymorphism and prostate cancer prompted this meta-analysis, to decipher the association between CYP17 polymorphism and prostate cancer. Most case-control studies addressing CYP17 polymorphism and prostate cancer were exhaustively searched from Web of Science, Google Scholar, and PubMed. The various genotype distributions as well as the minor allele distributions were retrieved. Pooled odds ratios (ORs) with their 95% CI and estimates of the Hardy–Weinberg Equilibrium were calculated. Analyses were performed using the RevMan v.5.3 software and SPSS v.21. There was high-pooled heterogeneity (I² = 87.0%, OR = .42, CI [.39, .45], and p < .001) among the A2 versus A1 allele. With the per-allele model (A2 versus A1), ethnicity was a major risk factor to prostate cancer, with Asians recording the highest risk (OR = 12.61, 95% CI [8.77, 18.12]). From the genotype models, A1/A1 versus A2/A2 (OR = 3.02, 95% CI [2.65, 3.44]) and A1/A2 versus A2/A2 (OR = 4.39, 95% CI [3.86, 5.00]) were all significantly associated with prostate cancer. Although some genotype models were associated with the risk of prostate cancer, we should be mindful when interpreting the results of this study because of the limited number of studies and the small sample size used.

Role of CYP17 rs743572 Polymorphism in Benign Prostatic Hyperplasia: A Multivariate Integrated Analysis

Objective: Many published studies have investigated the association between CYP17 rs743572 polymorphism and benign prostatic hyperplasia (BPH) susceptibility but have yielded inconsistent results. Hence, we performed this meta-analysis using the multivariate statistic method to address a more precise association.

Methods: Case-control or cohort studies with adequate genotype distribution or minor allele frequency (MAF) were identified by searching the PubMed, Embase, and Web of Science databases up to December, 2018. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the association between CYP17 rs743572 polymorphism and BPH susceptibility.

Results: Pooled MAFs of 13 studies were 37% in Caucasians and 56% in Orientals, respectively. Pooled results of 8 studies suggested that CYP17 rs743572 was not associated with the BPH susceptibility in the overall population (OR = 0.98, 95% CI: 0.80–1.20 for A2 vs. A1; OR = 0.99, 95% CI: 0.79–1.25 for A1/A2 vs. A1/A1; OR = 0.97, 95% CI: 0.62–1.53 for A2/A2 vs. A1/A1). Sensitivity analysis showed the results were robust. Subgroup analysis based on ethnicity suggested that, in Orientals, A2 allele carriers had a 28% lower risk of developing BPH compared with A1 allele carriers, and the risk of BPH is 47% lower in A2/A2 genotype carriers compared with A1/A1 genotype carriers. No significant association was observed in Caucasians.

Conclusion: In conclusion, our study indicates a negative association between CYP17 and BPH in Orientals. However, due to limited sample size, the conclusion should be interpreted with caution.

ESR1 PvuII (rs2234693 T>C) polymorphism and cancer susceptibility: Evidence from 80 studies

Emerging epidemiological researches have been performed to assess the association of ESR1 PvuII (rs2234693 T>C) polymorphism with the risk of cancer, yet with conflicting conclusions. Therefore, this updated meta-analysis was performed to make a more accurate evaluation of such relationship. We adopted EMBASE, PubMed, CNKI, and WANFANG database to search relevant literature before January 2018. Odds ratios (ORs) and 95% confidence intervals (CIs) were employed to estimate the relationship strengths. In final, 80 studies (69 publications) involving 26428 cases and 43381 controls were enrolled. Our results failed to provide significant association between overall cancer risk and PvuII polymorphism under homozygous (TT vs. CC) and heterozygous (TT vs. CT) models. Statistically significant relationship was only observed for PvuII polymorphism in allele model T vs. C (OR=0.95, 95% CI=0.91-0.99). Stratification analysis by cancer type suggested that T genotype significantly decreased prostate cancer risk (TT vs. CC: OR=0.79, 95% CI=0.66-0.94; T vs. C: OR=0.89, 95% CI=0.82-0.98), Leiomyoma risk (T vs. C: OR=0.82, 95% CI=0.68-0.98), and HCC risk (TT vs. CC: OR=0.45, 95% CI=0.28-0.71; T vs. C: OR=0.67, 95% CI=0.47-0.95). Furthermore, significantly decreased risk was also found for Africans, population-based and hospital-based studies in the stratified analyses. These results suggest that ESR1 PvuII (rs2234693 T>C) polymorphism may only have little impact on cancer susceptibility. In the future, large-scale epidemical studies are warranted to verify these results.

Genetic association between PSA-158G/A polymorphism and the susceptibility of benign prostatic hyperplasia: a meta-analysis

Inconsistency between reported findings on the association of prostate specific antigen (PSA) gene -158G/A polymorphism with benign prostatic hyperplasia (BPH) susceptibility need a meta-analysis to obtain a more accurate conclusion. A systematic search was conducted in electronic databases for the collection of eligible studies on PSA -158G/A polymorphism and BPH susceptibility. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were then calculated. 7 case-control studies with 758 cases and 752 controls were included into the present meta-analysis. The analysis results showed no significant relationship between PSA -158G/A polymorphism and BPH susceptibility in total analysis. Interestingly, after subgroup analyses based on ethnicity and source of control, the polymorphism reduced the susceptibility of BPH in Caucasian group (AA vs. GG: OR=0.47, 95% CI=0.25-0.89; allele A vs. allele G: OR=0.68, 95% CI=0.49-0.93), but it increased the disease susceptibility in Asian (AA vs. GG: OR=1.63, 95% CI=1.02-2.60; allele A vs. allele G: OR=1.37, 95% CI=1.03-1.83) and population-based (AA vs. GG: OR=2.39, 95% CI=1.07-5.38; allele A vs. allele G: OR=1.83, 95% CI=1.26-2.65) groups. PSA-158G/A polymorphism may be an inhibitor to the incidence of BPH in Caucasians, but it is likely to be a susceptible factor in Asians.

Comprehensive assessment of the association between estrogen receptor of alpha polymorphisms and the risk of prostate cancer: evidence from a meta-analysis

We performed a meta analysis to access the relationship of estrogen receptor of alpha (ESRα) polymorphisms with the risk of prostate cancer (PC). Twenty-four case-control studies (including 5477 cases and 10708 controls) were recruited for meta-analysis. The strongest association with the risk of PC was observed between ESRα rs9340799 and rs2234693 under the two genotypic models of allele and codominance in the overall population (p < 0.05). Under the subgroup analysis of ethnicity, we observed that ESRα rs9340799 was significantly associated with the susceptibility to PC in European population (AvsG, p = 0.000; AAvsGG, p = 0.002), while there was no difference in Asian (AvsG, p = 0.493; AAvsGG, p = 0.736) or African population (AvsG, p = 0.800; AAvsGG, p = 0.788). The results also showed that significant association between rs2234693 and the susceptibility to PC in European (CvsT, p = 0.004; CCvsTT, p = 0.001) and Asian population (CvsT, p = 0.004; CCvsTT, p = 0.003), but not in African population (CvsT, p = 0.636; CCvsTT, p = 0.669). The meta-analysis indicated that ESRα rs9340799 and rs2234693 might contribute to susceptibility and development of PC in European population.

Association of estrogen receptor α PvuII and XbaI polymorphisms with prostate cancer susceptibility and risk stratification: a meta-analysis from case-control studies

Background

Studies on the association between two single nucleotide polymorphisms (SNPs) in estrogen receptor α (ERα), PvuII (rs2234693 T>C) and XbaI (rs9340799 A>G), and the prostate cancer risk are inconsistent. Therefore, we performed a meta-analysis to derive a more accurate estimation of this relationship.

Methods

A literature search of PubMed, Embase, Web of Science databases until October 1, 2016, was conducted. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of this association.

Results

Eighteen case-control studies, with a total of 3,317 prostate cancer patients and 8,324 controls, were included. Results showed that both PvuII and XbaI polymorphisms were significantly associated with a higher prostate cancer risk in overall populations. To derive a more accurate estimation, subgroup analysis stratified by ethnicity revealed that this relation-ship existed only in Caucasians, but not in Asians. Furthermore, PvuII polymorphism was significantly associated with high Gleason grade (Gleason score ≥7) cancers.

Conclusion

The current meta-analysis demonstrates that ERα PvuII and XbaI polymorphisms are associated with a higher prostate cancer risk in Caucasians, but not in Asians, and PvuII polymorphism is significantly associated with high Gleason grade tumors, indicating the probability of inherited susceptibility to prostate cancer arising from different genomic ERα SNPs, which may help us understand the pathogenesis of prostate cancer in Caucasians.

Relationship of oestrogen receptor alpha gene polymorphisms with risk for benign prostatic hyperplasia and prostate cancer in Chinese men

The relationship of oestrogen receptor with benign prostatic hyperplasia (BPH) and prostate cancer (PC) is not clear at present. This study aimed to investigate the molecular mechanism underlying the occurrence and development of BPH and prostate.Two hundred forty-four PC cases, 260 BPH patients, and 222 healthy men were recruited from Han people in China, and the oestrogen receptor alpha (ESRα) gene polymorphism (rs2234693 [PvuII] and rs9340799 [XbaI]) on intron 1 was determined. The relationship of gene polymorphism with PC and BPH was evaluated with Logistic regression, and the linkage disequilibrium and haplotyping were assessed with SHEsis software.The risk for PC in BPH patients with PvuII C allele was higher (OR = 1.437, 95% CI: 1.110-1.859), but the differentiation degree of cancer cells was relatively better in PC patients with PvuII C allele (OR = 0.419, 95% CI: 0.285-0.616), and most of them are circumscribed (OR = 0.706, 95% CI: 0.485-1.02). There was significant linkage disequilibrium between PvuII and XbaI. The genotype TTAG not only induced BPH (OR = 6.260, 95% CI: 1.407-27.852), but increased the risk for PC (OR = 6.696, 95% CI: 1.504-29.801). However, the genotype TTAG in BPH patients had no relationship with the risk for PC (P > 0.05). Furthermore, men with haplotype TG were more likely to suffer PC (OR = 9.168, 95% CI: 2.393-35.119), but men with haplotype TA and enlarged prostate had a low risk for PC (OR = 0.708, 95% CI: 0.551-0.912).These results show the relationship between ESRα gene polymorphism and susceptibility to PC and BPH in Chinese men, and the ethnic and regional difference as well.

SRD5A2 gene polymorphisms and the risk of benign prostatic hyperplasia but not prostate cancer

BACKGROUND

Testosterone, a primary androgen in males, is converted into its most active form, dihydrotestosterone (DHT), by 5α-reductase type 2 (encoded by the SRD5A2 gene) in the prostate. DHT is necessary for prostatic growth and has five times higher binding affinity than testosterone for androgen receptors. We hypothesized that polymorphic variations in the SRD5A2 gene may affect the risk of benign prostatic hyperplasia and prostate cancer.

MATERIALS AND METHODS

We analyzed SRD5A2 gene polymorphisms in 217 BPH patients, 192 PCa cases, and 171 controls. Genotyping was undertaken using direct DNA sequencing. Genotype data were compared between cases and controls using a Chi square statistical tool.

RESULTS

We found that the A49T locus was monomorphic with 'AA' genotype in all subjects. At V89L locus, the presence of 'VV' showed a marginally significant correlation with increased BPH risk (p=0.047). At the (TA)n locus, longer TA repeats were found to be protective against BPH (p=0.003). However, neither of these polymoprhisms correlated with the risk of PCa.

CONCLUSIONS

We conclude that A49T is monomorphic in the study population, VV marginally correlates with BPH risk, and longer (TA)n repeats are protective against BPH. None of these polymorphisms affect the risk of PCa.

Estrogen receptor 1 (ESR1) genetic variations in cancer risk: a systematic review and meta-analysis

BACKGROUND

Emerging published data on the association between single nucleotide polymorphisms (SNPs) in the estrogen receptor 1 (ESR1) gene and cancer susceptibility are inconsistent. This review and meta-analysis is performed to derive a more precise evaluation of this relationship.

METHODS

The literature search of PubMed, Embase, Web of Science and CNKI databases was conducted from their inception through June 2014. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association.

RESULTS

Twenty-two literatures were enrolled in this meta-analysis. The results indicated that ESR1 rs1801132 (C>G) was associated with cancer risk in Caucasian populations. However, the results of stratified analysis by cancer type and source of controls indicated that no significant association was found. Furthermore, rs2077647 (A>G) was only associated with an increased risk of hepatocellular carcinoma, but was an adverse effect on cancer risk in Caucasian populations.

CONCLUSIONS

This present meta-analysis indicated that rs1801132 (C>G) and rs2077647 (A>G) may be protective factors in Caucasian populations. Meanwhile, rs2077647 (A>G) may be closely related with hepatocellular carcinoma.

Genetic variation: effect on prostate cancer

The crucial role of androgens in the development of prostate cancer is well established. The aim of this review is to examine the role of constitutional (germline) and tumor-specific (somatic) polymorphisms within important regulatory genes of prostate cancer. These include genes encoding enzymes of the androgen biosynthetic pathway, the androgen receptor gene, genes that encode proteins of the signal transduction pathways that may have a role in disease progression and survival, and genes involved in prostate cancer angiogenesis. Characterization of deregulated pathways critical to cancer cell growth have lead to the development of new treatments, including the CYP17 inhibitor abiraterone and clinical trials using novel drugs that are ongoing or recently completed [1]. The pharmacogenetics of the drugs used to treat prostate cancer will also be addressed. This review will define how germline polymorphisms are known affect a multitude of pathways, and therefore phenotypes, in prostate cancer etiology, progression, and treatment.

Quantitative assessment of the association between CYP17 rs743572 polymorphism and prostate cancer risk

Published data on the association between CYP17 rs743572 polymorphism and risk of PC showed inconclusive results. The aim of this study was to further estimate the pooled effect size of rs743572 polymorphism and PC progression via large-scale meta-analysis. We searched the case-control studies of rs743572 polymorphism and PC risk in PubMed, Embase, and Web of Science databases up to February 2014. Odds ratios (ORs) along with 95 % confidence intervals (CIs) were pooled by means of both fixed effects model and random effects model. A total of 38 publications consisting of 42 studies with 15,735 cases and 17,825 controls were included in this meta-analysis. Overall, no significant association was found between rs743572 polymorphism and PC risk. Stratified analyses by control source and sample size did not provide significant results. However, there was a borderline association in African population under A2A2 versus A1A2 + A1A1 genetic model (OR = 1.39, 95 % CI: 1.01-1.92, P = 0.975, I (2) = 0.0 %). Results from the current meta-analysis suggested that CYP17 rs743572 polymorphism might modify the risk of PC in the subjects of African decent.

Systematic review and meta-analysis of candidate gene association studies of lower urinary tract symptoms in men

Context

Although family studies have shown that male lower urinary tract symptoms (LUTS) are highly heritable, no systematic review exists of genetic polymorphisms tested for association with LUTS.

Objective

To systematically review and meta-analyze studies assessing candidate polymorphisms/genes tested for an association with LUTS, and to assess the strength, consistency, and potential for bias among pooled associations.

Evidence acquisition

A systematic search of the PubMed and HuGE databases as well as abstracts of major urologic meetings was performed through to January 2013. Case-control studies reporting genetic associations in men with LUTS were included. Reviewers independently and in duplicate screened titles, abstracts, and full texts to determine eligibility, abstracted data, and assessed the credibility of pooled associations according to the interim Venice criteria. Authors were contacted for clarifications if needed. Meta-analyses were performed for variants assessed in more than two studies.

Evidence synthesis

We identified 74 eligible studies containing data on 70 different genes. A total of 35 meta-analyses were performed with statistical significance in five (ACE, ELAC2, GSTM1, TERT, and VDR). The heterogeneity was high in three of these meta-analyses. The rs731236 variant of the vitamin D receptor had a protective effect for LUTS (odds ratio: 0.64; 95% confidence interval, 0.49–0.83) with moderate heterogeneity (I² = 27.2%). No evidence for publication bias was identified. Limitations include wide-ranging phenotype definitions for LUTS and limited power in most meta-analyses to detect smaller effect sizes.

Conclusions

Few putative genetic risk variants have been reliably replicated across populations. We found consistent evidence of a reduced risk of LUTS associated with the common rs731236 variant of the vitamin D receptor gene in our meta-analyses.

Patient summary

Combining the results from all previous studies of genetic variants that may cause urinary symptoms in men, we found significant variants in five genes. Only one, a variant of the vitamin D receptor, was consistently protective across different populations.

Association between estrogen receptor alpha PvuII polymorphism and prostate cancer risk

Accumulating evidence has suggested that estrogen receptor alpha (ER-α) PvuII polymorphism might be involved in the development of prostate cancer (PCa). However, the results have been inconsistent. We therefore performed a meta-analysis to clarify the associations between ER-α PvuII polymorphism and PCa. A comprehensive search was conducted to identify all case-control studies of ER-α PvuII polymorphism and PCa risk. We used odds ratios (ORs) to assess the strength of the association and 95% confidence intervals (CIs) to give a sense of the precision of the estimate. A total of 14 studies were found to be eligible for meta-analyses of PvuII variant. Results from this study showed that ER-α PvuII polymorphism were significantly associated with PCa risk under all genetic models in overall population (homogeneous codominant model, OR = 1.57, 95% CI = 1.11-2.21, P = 0.010; heterogeneous codominant model, OR = 1.37, 95% CI = 1.06-1.77, P = 0.02; recessive model, OR = 1.27, 95% CI = 1.02-1.57, P = 0.03; dominant model, OR = 1.40, 95% CI = 1.09-1.79, P = 0.009; and allelic model, OR = 1.25, 95% CI = 1.06-1.48, P = 0.010). Further sensitivity analysis confirmed the significant association. In subgroup analyses stratified by PCa type, there was a significant association between PvuII polymorphism and sporadic PCa risk under both Caucasians and Asians. The meta-analysis indicated elected PvuII polymorphism of ER-α was a risk factor for PCa development.

ESR1 Gene Polymorphisms and Prostate Cancer Risk: A HuGE Review and Meta-Analysis

BACKGROUND

Many published data on the association between single nucleotide polymorphisms (SNPs) in the ESR1 gene and prostate cancer susceptibility are inconclusive. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis is to derive a more precise estimation of this relationship.

METHODS

A literature search of PubMed, Embase, Web of Science and Chinese Biomedical (CBM) databases was conducted from their inception through July 1st, 2012. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of association.

RESULTS

Twelve case-control studies were included with a total 2,165 prostate cancer cases and 3,361 healthy controls. When all the eligible studies were pooled into the meta-analysis, ESR1 PvuII (C>T) and XbaI (A>G) polymorphisms showed no association with the risk of prostate cancer. However, in the stratified analyses based on ethnicity and country, the results indicated that ESR1 PvuII (C>T) polymorphism was significantly associated with increased risk of prostate cancer among Asian populations, especially among Indian population; while ESR1 XbaI (A>G) polymorphism may significantly increase the risk of prostate cancer among American population. Furthermore, we also performed a pooled analysis for all eligible case-control studies to explore the role of codon 10 (T>C), codon 325 (C>G), codon 594 (G>A) and +261G>C polymorphisms in prostate cancer risk. Nevertheless, no significant associations between these polymorphisms and the risk of prostate cancer were observed.

CONCLUSION

Results from the current meta-analysis indicate that ESR1 PvuII (C>T) polymorphism may be a risk factor for prostate cancer among Asian populations, especially among Indian population; while ESR1 XbaI (A>G) polymorphism may increase the risk of prostate cancer among American population.

Steroid 5-alpha-reductase type 2 (SRD5A2) V89L and A49T polymorphisms and sporadic prostate cancer risk: a meta-analysis

Steroid 5-α-reductase type 2 (SRD5A2) V89L and A49T polymorphisms are thought to play a crucial role in the androgen synthesis and metabolic pathway, but their associations with prostate cancer risk remain controversial. To provide a more precise estimation of the associations between V89L and A49T polymorphisms and prostate cancer risk, we performed a meta-analysis using all published case-control studies of prostate cancer since January 1995. We used odds ratio (OR) and its 95% confidence interval (CI) to assess the strength of the association under various genetic models in both overall and stratified analyses. We also calculated the false-positive report probability, the power of the current study, and the observed P value for significant findings. This analysis included 45 eligible studies of a total of 15,562 cases and 15,385 controls, in which no significant associations were found for the V89L polymorphisms under all genetic models. However, small excess prostate cancer risk was associated with the 49T allele in mixed populations compared with the 49A allele (OR = 1.24, 95% CI = 1.02-1.50), and similar results were observed in Caucasians (OR = 1.24, 95% CI = 1.01-1.53). The sensitivity analysis further strengthened the validity of these findings without publication bias. Although there was no overall association between V89L and prostate cancer risk, A49T might play a role in the etiology of prostate cancer among Caucasians. Additional large and well-designed studies are warranted to validate these findings.

CYP17 T27C polymorphism and prostate cancer risk: a meta-analysis based on 31 studies

Objective

The cytochrome P450 17α-hydroxylase (CYP17) plays a vital role in androgen biosynthesis. A T-to-C polymorphism in the 5′ promoter region of CYP17 has been implicated as a risk factor for prostate cancer, but the results of individual studies are inconclusive or controversial. To derive a more precise estimation of the relationship, we performed an updated meta-analysis from 31 studies based on 27 publications.

Methods

A comprehensive search was conducted to examine all the eligible studies of CYP17 polymorphism and prostate cancer risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association.

Results

Overall, individuals with CC/CT genotype were not associated with prostate cancer risk (CC vs. TT: OR = 1.03, 95% CI = 0.86-1.24, P = 0.72, P_{heterogeneity} < 0.0001; CT vs. TT: OR = 0.99, 95% CI = 0.87-1.12, P = 0.88, P_{heterogeneity} = 0.0006). In the stratified analysis by ethnicity, there was a significantly increased risk of prostate cancer among individuals of African descent under the recessive model (OR = 1.56, 95% CI = 1.01-2.39, P = 0.04, P_{heterogeneity} = 0.65).

Conclusion

This meta-analysis suggested that CYP17 polymorphism might be associated with prostate cancer risk among individuals of African descent.

Effect of CYP17 and PSA gene polymorphisms on prostate cancer risk and circulating PSA levels in the Slovak population

Cytochrome P-450c17α (CYP17) and prostate-specific antigen (PSA) genes, which are involved in the androgen metabolism cascade, have been studied as possible candidates for genetic influences on prostate cancer development. Contradictory results prompted us to evaluate the frequencies of polymorphisms in the CYP17 and PSA genes as well as the association between these genetic variants and serum PSA levels in prostate cancer patients and men routinely screened for prostate cancer with PSA in the Slovak male population. The CYP17 and PSA polymorphisms were determined by the PCR-RFLP analysis in 197 Caucasian prostate cancer patients and 256 Caucasian controls. We did not find any association between the CYP17 and PSA genotypes and prostate cancer risk overall, or by grade. Also the total serum PSA levels in the cases with the AG or AA genotype were not significantly higher than in the men with the GG genotype (P > 0.05). Our study did not provide support for the hypothesized relationship between CYP17 and PSA gene polymorphisms and prostate cancer in the Slovak male population.

Pattern Discovery from Biological Data

Extracting useful information from structured and unstructured biological data is crucial in the health industry. Some examples include medical practitioner’s need to identify breast cancer patient in the early stage, estimate survival time of a heart disease patient, or recognize uncommon disease characteristics which suddenly appear. Currently there is an explosion in biological data available in the data bases. But information extraction and true open access to data are require time to resolve issues such as ethical clearance. The emergence of novel IT technologies allows health practitioners to facilitate the comprehensive analyses of medical images, genomes, transcriptomes, and proteomes in health and disease. The information that is extracted from such technologies may soon exert a dramatic change in the pace of medical research and impact considerably on the care of patients. The current research will review the existing technologies being used in heart and cancer research. Finally this research will provide some possible solutions to overcome the limitations of existing technologies. In summary the primary objective of this research is to investigate how existing modern machine learning techniques (with their strength and limitations) are being used in the indent of heartbeat related disease and the early detection of cancer in patients. After an extensive literature review these are the objectives chosen: to develop a new approach to find the association between diseases such as high blood pressure, stroke and heartbeat, to propose an improved feature selection method to analyze huge images and microarray databases for machine learning algorithms in cancer research, to find an automatic distance function selection method for clustering tasks, to discover the most significant risk factors for specific cancers, and to determine the preventive factors for specific cancers that are aligned with the most significant risk factors. Therefore we propose a research plan to attain these objectives within this chapter. The possible solutions of the above objectives are: new heartbeat identification techniques show promising association with the heartbeat patterns and diseases, sensitivity based feature selection methods will be applied to early cancer patient classification, meta learning approaches will be adopted in clustering algorithms to select an automatic distance function, and Apriori algorithm will be applied to discover the significant risks and preventive factors for specific cancers. We expect this research will add significant contributions to the medical professional to enable more accurate diagnosis and better patient care. It will also contribute in other area such as biomedical modeling, medical image analysis and early diseases warning.

CYP17 gene polymorphisms and prostate cancer risk: a meta-analysis based on 38 independent studies

BACKGROUND

The results of recent published studies focusing on CYP17 polymorphisms in prostate cancer (PCa) susceptibility are often conflicting. We performed a meta-analysis based on 38 independent studies to evaluate the association.

METHODS

Data were collected from the following electronic databases: PubMed, Excerpta Medica Database, and Chinese Biomedical Literature Database, with the last report up to September 2010. Meta-analysis was conducted in a fixed/random effect model.

RESULTS

Thirty-eight independent studies including 34,782 cases and 38,626 controls on the association of CYP17 gene polymorphisms with PCa risk in different ethnic groups were identified. The meta-analysis was performed for five polymorphisms: rs743572 (A1/A2, 38 studies), rs6162 (C/T, 3 studies), rs619824 (C/A, 4 studies), rs2486758 (T/C, 4 studies), and rs10883782 (A/G, 4 studies). When all groups were pooled, we did not detect the association of rs743572 polymorphism with PCa risk. In the subgroup analysis, a significant association of rs743572 polymorphism and PCa was found in Black population (A2/A2 vs. A1/A1 + A2/A1: OR = 1.70, 95% CI = 1.08-2.69, P = 0.02), but not in Caucasian or Asian population. For other polymorphisms, we found that rs619824 polymorphism was associated with a significant decreased risk of PCa (A vs. C: OR = 0.95, 95% CI = 0.92-0.99, P = 0.01), and rs2486758 polymorphism was associated with a significant increased risk of PCa (C vs. T: OR = 1.07, 95% CI = 1.03-1.12, P = 0.002).

CONCLUSION

This meta-analysis suggests that rs743572 polymorphism is associated with PCa risk in Black population, but not in Caucasian or Asian population. Moreover, our study suggests that rs619824 and rs2486758 polymorphisms are associated with PCa risk.

CYP17 gene polymorphism and prostate cancer susceptibility in a Tunisian population

Prostate cancer (PCa) formation has been reported to be associated with androgen. Two key steps in the sex steroid synthesis are mediated by the enzyme cytochrome P450c 17α which is encoded in the CYP17 gene. The A2 allele of the CYP17 gene has been thought to be associated with increased functional activity of this steroidogenic enzyme. Consequently, the A2 allele has been examined as a biomarker of individual susceptibility to hormone-related diseases among men. We prospectively assessed the association between the A2 allele of CYP17 and PCa risk among 125 cases and 125 controls in a case-control study. Our aim was to investigate whether a polymorphism of CYP17 gene could be used as a genetic marker for associating PCa. The result revealed a significant association between the CYP17 polymorphic genotypes and PCa. Therefore, CYP17 gene polymorphism is likely contributed to the pathogenesis of PCa but not to disease severity.

Meta-analysis of three polymorphisms in the steroid-5-alpha-reductase, alpha polypeptide 2 gene (SRD5A2) and risk of prostate cancer

The steroid-5-alpha-reductase, alpha polypeptide 2 (SRD5A2) gene plays a crucial role in androgen metabolism pathway in human prostate. It encodes SRD5A2 enzyme, which catalyses testosterone to dihydrotestosterone (DHT). DHT is the main active structure binding with androgen receptor (AR). After the activation of AR, it further regulates a series of target genes in androgen metabolism pathway. However, no clear consensus has been reached on the association between the SRD5A2 V89L, A49T and TA repeat polymorphisms and prostate cancer (PCa) risk. Thus, we performed a meta-analysis of 31 association studies with 14,726 PCa cases and 15,802 controls. We found no association between PCa and 89L compared with 89V allele [odds ratio (OR) = 1.02, 95% confidence interval (CI) 0.98-1.06, P(heterogeneity) = 0.44]. The 49T allele showed a significantly elevated effect on the high stage (Stages III-IV) of PCa risk both under the dominant genetic model (OR = 2.13, 95% CI 1.44-3.15, P(heterogeneity) = 0.65) and in the contrast T versus A allele (OR = 2.06, 95% CI 1.41-3.02, P(heterogeneity) = 0.69). There was a significantly decreased association between PCa and long TA repeat as compared versus short TA repeat (OR = 0.86, 95% CI 0.74-1.00, P(heterogeneity) = 0.79). No significant between-study heterogeneity was found in all subjects under four genetic models (dominant model, recessive model, allele comparison and homozygosity comparison) for these three polymorphisms, respectively, so the fixed effects model was used to pool the result. Our result indicated that carriers of 49T might improve the risk of PCa in higher stages (Stages III-IV), carriers of long TA repeat might decrease the risk of PCa and 89L may not be an important risk factor for PCa. However, due to the limited sample sizes, this meta-analysis did not achieve sufficiently conclusive results. Still more well-designed studies should be performed to clarify the role of these three polymorphisms in the development of PCa.

Single and multigenic analysis of the association between variants in 12 steroid hormone metabolism genes and risk of prostate cancer

To estimate the prostate cancer risk conferred by individual single nucleotide polymorphisms (SNPs), SNP-SNP interactions, and/or cumulative SNP effects, we evaluated the association between prostate cancer risk and the genetic variants of 12 key genes within the steroid hormone pathway (CYP17, HSD17B3, ESR1, SRD5A2, HSD3B1, HSD3B2, CYP19, CYP1A1, CYP1B1, CYP3A4, CYP27B1, and CYP24A1). A total of 116 tagged SNPs covering the group of genes were analyzed in 2,452 samples (886 cases and 1,566 controls) in three ethnic/racial groups. Several SNPs within CYP19 were significantly associated with prostate cancer in all three ethnicities (P = 0.001-0.009). Genetic variants within HSD3B2 and CYP24A1 conferred increased risk of prostate cancer in non-Hispanic or Hispanic Caucasians. A significant gene-dosage effect for increasing numbers of potential high-risk genotypes was found in non-Hispanic and Hispanic Caucasians. Higher-order interactions showed a seven-SNP interaction involving HSD17B3, CYP19, and CYP24A1 in Hispanic Caucasians (P = 0.001). In African Americans, a 10-locus model, with SNPs located within SRD5A2, HSD17B3, CYP17, CYP27B1, CYP19, and CYP24A1, showed a significant interaction (P = 0.014). In non-Hispanic Caucasians, an interaction of four SNPs in HSD3B2, HSD17B3, and CYP19 was found (P < 0.001). These data are consistent with a polygenic model of prostate cancer, indicating that multiple interacting genes of the steroid hormone pathway confer increased risk of prostate cancer.

Genetic polymorphisms of estrogen receptors alpha and beta and the risk of developing prostate cancer

Estrogen may be involved in the development of prostate cancer. The association between genetic polymorphisms of estrogen receptors α (ESR1) and β (ESR2) and prostate cancer risk was examined in a nested case-control study in Washington County, Maryland. Incident prostate cancer cases (n = 269) were matched to one or two controls (n = 440) by age, sex, race, and date of blood donation. Associations between estrogen receptor genotypes or dietary intake and the development of prostate cancer were examined in conditional logistic regression models. Results from this study showed that six single base-pair polymorphisms (SNPs) of ESR1 (rs1801132, rs2077647, rs746432, rs2273206, rs851982, rs2228480) and four SNPs of ESR2 (rs4986938, rs928554, rs8018687, rs number not available for ESR2 5696 bp 3′ of STP A>G) were not significantly associated with prostate cancer risk, either by allelic or genotypic frequencies. However, an interactive association with BMI was observed in the relationship between prostate cancer risk and genotypes of ESR2 38 bp 3′ of STP G>A (rs4986938) (p = 0.031). An interaction between intake level of phytoestrogen and genotypes of ESR1 Ex1-192G>C (rs746432) and between intake level of phytoestrogen and genotypes of ESR1 Ex8+229G>A (rs2228480) and risk of prostate cancer was observed (p = 0.0009 and p = 0.044, respectively). In conclusion, selected genetic polymorphisms of ESR1 and ESR2, overall, were not associated with prostate cancer risk. However, a variation in risk by BMI and phytoestrogen intake was implicated.