Association between an estrogen receptor alpha gene polymorphism and the risk of prostate cancer in black men

Single Nucleotide Polymorphisms Associated with Prostate Cancer Progression: A Systematic Review

BACKGROUND

New biomarkers of progression in patients with prostate cancer (PCa) are needed to improve their classification and clinical management. This systematic review investigated the relationship between single nucleotide polymorphisms (SNPs) and PCa progression.

METHODS

A keyword search was performed in Pubmed, EMBASE, Scopus, Web of Science, and Cochrane for publications between 2007 and 2022. We included articles with adjusted and significant associations, a median follow-up greater than or equal to 24 months, patients taken to radical prostatectomy (RP) as a first therapeutic option, and results presented based on biochemical recurrence (BCR).

RESULTS

In the 27 articles selected, 73 SNPs were identified in 39 genes, organized in seven functional groups. Of these, 50 and 23 SNPs were significantly associated with a higher and lower risk of PCa progression, respectively. Likewise, four haplotypes were found to have a significant association with PCa progression.

CONCLUSION

This article highlights the importance of SNPs as potential markers of PCa progression and their possible functional relationship with some genes relevant to its development and progression. However, most variants were identified only in cohorts from two countries; no additional studies reproduce these findings.

Carriage of mutations R462Q (rs 486907) and D541E (rs 627928) of the RNASEL gene and risk factors in patients with prostate cancer in Burkina Faso

Background

Prostate cancer (Pca) is a public health problem that affects men, usually of middle age or older. It is the second most common cancer diagnosed in men and the fifth leading cause of death. The RNASEL gene located in 1q25 and identified as a susceptibility gene to hereditary prostate cancer, has never been studied in relation to prostate cancer in Burkina Faso. The aim of this study was to analyze the carriage of RNASEL R462Q and D541E mutations and risks factors in patients with prostate cancer in the Burkina Faso.

Methods

This case–control study included of 38 histologically diagnosed prostate cancer cases and 53 controls (cases without prostate abnormalities). Real-time PCR genotyping of R462Q and D541E variants using the TaqMan® allelic discrimination technique was used. Correlations between different genotypes and combined genotypes were investigated.

Results

The R462Q variant was present in 5.3% of cases and 7.5% of controls. The D541E variant was present in 50.0% of cases and 35% of controls. There is no association between R462Q variants (OR = 0.60; 95%IC, 0.10–3.51; p = 0.686) and D541E variants (OR = 2.46; 95%IC, 0.78–7.80; p = 0.121) and genotypes combined with prostate cancer. However, there is a statistically significant difference in the distribution of cases according to the PSA rate at diagnosis (p ˂ 0.001). For the Gleason score distribution, only 13.2% of cases have a Gleason score greater than 7. There is a statistically significant difference in the Gleason score distribution of cases (p ˂ 0.001).

Conclusions

These variants, considered in isolation or in combination, are not associated with the risk of prostate cancer.

A network-based integration for understanding racial disparity in prostate cancer

Compared to Caucasians (CAs), African Americans (AAs) have a higher rate of incidence and mortality in prostate cancer and are prone to be diagnosed at later stages. To understand this racial disparity, molecular features of different types, including gene expression, DNA methylation and other genomic alterations, have been compared between tumor samples from the two races, but led to different disparity associated genes (DAGs). In this study, we applied a network-based algorithm to integrate a comprehensive set of genomic datasets and identified 130 core DAGs. Out of these genes, 78 were not identified by any individual dataset but prioritized and selected through network propagation. We found DAGs were highly enriched in several critical prostate cancer-related signaling transduction and cell cycle pathways and were more likely to be associated with patient prognosis in prostate cancer. Furthermore, DAGs were over-represented in prostate cancer risk genes identified from previous genome wide association studies. We also found DAGs were enriched in kinase and transcription factor encoding genes. Interestingly, for many of these prioritized kinases their association with racial disparity did not manifest from the original genomic/transcriptomic data but was reflected by their differential phosphorylation levels between AA and CA prostate tumor samples. Similarly, the disparity relevance of some transcription factors was not reflected at the mRNA or protein expression level, but at the activity level as demonstrated by their differential ability in regulating target gene expression. Our integrative analysis provided new candidate targets for improving prostate cancer treatment and addressing the racial disparity problem.

Expression of cyclin D1, p21, and estrogen receptor alpha in aflatoxin G1-induced disturbance in testicular tissue of albino mice

Background and purpose

Aflatoxin (AF) is a mycotoxin produced by various strains of the Aspergillus family. AFG1 as one of the most important types is highly found in cereals and grains. AF affects sperm production or even its quality. This study was designed to test the effects of AFG1 on mice testicular tissue.

Experimental approach

Twenty-four Albino mice were divided into four groups of 6 each; a control group (0.2 mL corn oil and ethanol), three treatment groups with different periods (20 μg/kg AFG1 for 7, 15, and 35 consecutive days). All treatments were applied intraperitoneally. Biosynthesis of cyclin D1, p21, and estrogen receptor alpha (ERα) proteins was evaluated by immunohistochemistry (IHC) staining. Levels of cyclin D1, p21, and ERα mRNA were evaluated by the real-time polymerase chain reaction (RT-PCR) technique. Tubular differentiation index (TDI), reproductive index (RI), and spermiogenesis indices were also analyzed.

Findings/Results

AFG1 increased the percentage of seminiferous tubules with negative TDI, RI, and SPI compared to the control group (P < 0.05). RT-PCR and IHC analyses illustrated time-dependent enhancement in p21 expression and cyclin D1 biosynthesis in AFG1-treated groups significantly (P < 0.05). While the protein and mRNA levels of ERα were significantly (P < 0.05) decreased in a time-dependent manner.

Conclusion and implications

The chronic exposure to AFG1 reduced the expression and synthesis of ERα, increased the expression and synthesis of p21 and cyclin D1, impaired apoptosis, which in turn could impair spermatogenesis.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

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.

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.

The influence of ESR1 rs9340799 and ESR2 rs1256049 polymorphisms on prostate cancer risk

Estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2) may play a role in the development of prostate cancer. Many studies focused on ESR1 rs9340799 and ESR2 rs1256049 polymorphisms to explore associations with prostate cancer risk. These studies showed inconsistent and conflicting results. The aim of this meta-analysis was to investigate the pooled association of ESR1 rs9340799 and ESR2 rs1256049 polymorphisms with prostate cancer risk. A systematic literature search was conducted to identify related studies (up to February 2014) in several online databases including PubMed, Google Scholar, CNKI and Wanfang online libraries. A total of 16 eligible articles were enrolled in this updated meta-analysis. The result suggested that ESR1 rs9340799 polymorphism was significantly associated with prostate cancer in overall populations (GG+GA vs. AA: P = 0.002; G vs. A: P = 0.004), Caucasians (GG+GA vs. AA: P = 0.008; G vs. A: P = 0.016) and Africans (GG+GA vs. AA: P = 0.005; G vs. A: P = 0.006), but not in Asians (GG+GA vs. AA: P = 0.462; G vs. A: P = 0.665). The result also showed that there was a significant association between ESR2 rs1256049 polymorphism and prostate cancer in Caucasians (AA+AG vs. GG: P = 0.016; A vs. G: P = 0.005), but no association in overall populations (AA+AG vs. GG: P = 0.826; A vs. G: P = 0.478), Asians (AA+AG vs. GG: P = 0.177; A vs. G: P = 0.703) and Africans (AA+AG vs. GG: P = 0.847; A vs. G: P = 0.707). The cumulative meta-analysis and sensitivity analysis showed the results were robust. In conclusion, this meta-analysis indicated that ESR1 rs9340799 polymorphism was associated with prostate cancer risk in overall populations, Caucasians and Africans, while ESR2 rs1256049 polymorphism was associated with prostate cancer risk in Caucasians. However, the biological mechanisms need to be further investigated.

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.

The association between estrogen receptor alpha polymorphisms and the risk of prostate cancer in Slovak population

The aim of our study was to evaluate the effect of two polymorphisms in the estrogen receptor alpha, PvuII and XbaI, on the development of prostate cancer within Slovak population, as well as their correlation with selected clinical characteristics. The study was performed using 311 prostate cancer patients and 256 healthy male controls. Both polymorphisms were significantly associated with higher risk of prostate cancer development. At the same time, the CC genotype of PvuII polymorphism (OR = 1.98; 95% CI 0.94-4.21; p = 0.05) and the AG genotype of XbaI polymorphism (OR = 1.74; 95% CI 1.0-3.02; p = 0.04) significantly contributed to the development of low-grade carcinoma, while the AG and GG genotypes of the XbaI polymorphism contributed mainly to the development of high-grade prostate cancer (OR = 1.83; 95% CI 1.12-3.01; p = 0.01 and OR = 2.13; 95% CI 1.06-4.19; p = 0.03, respectively). Similarly, the AG and GG genotypes of XbaI polymorphism showed significant association with prostate cancer in patients with serum PSA level ≥10 ng/ml. Both polymorphisms were found at the same time to be more frequent in patients diagnosed before the age of 60. We conclude on the basis of these results that PvuII and XbaI polymorphisms of estrogen receptor alpha might be associated with prostate cancer risk within Slovak population. Although this is a pilot study and, as such, more detailed investigations are needed to confirm the role of these polymorphisms in prostate cancer development and progression within said Slovak population, our results might still provide a valuable basis for further research with larger patient groups.

A study on the estrogen receptor α gene polymorphism and its expression in thin endometrium of unknown etiology

BACKGROUND/AIMS

To study the relationship between the estrogen receptor α (ERa) gene polymorphism and expression in thin endometrium.

METHODS

We chose 120 unknown thin endometrium patients as the case group and another 112 normal endometrium women as the control group. Methods in molecular biology were used to analyze restriction fragment length polymorphism of PvuII and XbaI in the ERa gene. RT-PCR and Western blot were used to investigate the expressions of the ERa at mRNA and protein levels.

RESULTS

P genotypic frequency was 47.1% in the case group and 30.0% in the control group; the OR was 2.076. X genotypic frequency in the case group was 20.8%, and 30.4% in the control group; the OR was 0.602. Restriction fragment length polymorphism of PvuII and XbaI in the two groups were distributed with polymorphisms. The mRNA and protein expressions of ERa decreased compared with that in the control group (p < 0.05).

CONCLUSIONS

ERa gene polymorphism is related to unknown thin endometrium, in which P allele may be the risk and X allele may be its guard factor. The expression of ERa decreases in thin endometrium compared with normal endometrium, and ERa may be related to the unknown etiological thin endometrium.

Association of estrogen receptor beta variants and serum levels of estradiol with risk of colorectal cancer: a case control study

Background

Endogenous estrogens may play a vital role in colorectal tumorigenesis. Estrogen receptor beta is the predominant subtype which mediates the biological effect of estrogens, while loss of expression of estrogen receptor beta has been indicated as a common step in the development of colorectal cancer (CRC). Epidemiological studies have revealed several functional polymorphisms of estrogen receptor beta (ESR2) for cancer risk, but relevant study in CRC is limited, particularly in men. This study aimed to investigate the association of circulating estradiol and variations of ESR2 with CRC risk in men.

Methods

We initiated a case–control study consisting of 390 patients with CRC and 445 healthy controls in men only. We genotyped ESR2 single nucleotide polymorphisms (SNPs) rs1256049 and rs4986938 and measured serum estradiol concentration using chemilluminescence immunoassay. Multivariable logistic regression model was performed to evaluate the associations between these variables and CRC risk.

Results

ESR2 rs1256049 CT/TT genotypes were associated with reduced risk of CRC (odds ratio [OR], 0.7, 95% confidence interval [CI], 0.5–1.0), while rs4986938 CT/TT genotypes were associated with increased risk of CRC (OR, 1.5, 95% CI, 1.0–2.1). In addition, the CRC risk increased with the number of risk genotypes of these two SNPs in a dose–response manner (P_trend, 0.003). Specifically, subjects carrying risk genotypes of both SNPs had the highest risk of CRC (OR, 2.0, 95% CI, 1.3–3.3.). Moreover, serum estradiol concentration alone was associated with risk of CRC in men (OR, 1.2, 95% CI, 1.0–1.3). However, individuals presenting both rs4986938 CT/TT genotypes and high level of serum estradiol had a high risk of CRC (OR, 2.3, 95% CI, 1.4–3.9), compared with those presenting CC genotype and low level of serum estradiol. The similar joint results were not observed for SNP rs1256049.

Conclusions

These results suggest that endogenous estrogen and genetic variations in ESR2 may individually, or more likely jointly, affect CRC risk in male Han Chinese population, while larger studies are needed to validate our findings.

Estrogen receptors alpha (rs2234693 and rs9340799), and beta (rs4986938 and rs1256049) genes polymorphism in prostate cancer: evidence for association with risk and histopathological tumor characteristics in Iranian men

We evaluated the effect of estrogen receptor (ER)-α and ER-β genes polymorphisms on development of prostate cancer (PCa) and its correlation with serum reproductive hormones and with clinicopathological characteristics in a sample of Iranian men. One hundred sixty-two men with PCa (mean age 63.7 ± 3.4 years) and 324 age-matched healthy controls (mean age 63.1 ± 3.2 years) were recruited in this study. Genotypes for ER-α and ER-β genes polymorphisms were identified by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Serum levels of reproductive hormones were also measured. Of PCa patients, 38.3%, and 61.7% had localized and advanced tumor, and 45.7%, and 54.3%, had low grade and high-grade cancer, respectively. There was a significant difference in genotype frequency distribution of ER-α gene polymorphism (P = 0.002), and ER-β gene polymorphism (P = 0.003) between cancer patients and controls. The ER-α Pvull C allele carriers (TC or CC) had a significantly increased risk of PCa compared with the TT homozygotes [odds ratio (OR) 3.12; 95% confidence interval (CI) 1.87-5.84, and OR = 4.73, 95% CI:2.44-7.33, respectively]. It was also found that the ER-α XbaI AG (OR = 4.36; 95% CI:2.47-6.68; P = 0.001) and ER-β AluI AG (OR = 2.66, 95% CI:1.61-4.16; P = 0.004) genotypes were significantly associated with increased risk of PCa. The ER-β RsaI genotype was not associated with PCa. Baseline serum free E2 levels tended to be lower in men with PCa (0.35 ± 0.04 pg/ml) compared to healthy men (0.48 ± 0.05 pg/ml). Genotypes which confer susceptibility for developing PCa, accompanied with lowest serum levels of free E2. In the Iranian population, genetic polymorphisms of the ER-α and ER-β genes may be involved in the etiology of PCa.

Hormones and prostate carcinogenesis: Androgens and estrogens

Prostate cancer is the leading non-skin malignancy detected in US males and the second cause of death due to male cancer in the US. Androgenic hormones are generally believed to be causatively associated with prostate carcinogenesis, but human evidence, mostly epidemiological, for this is minimal. Circulating hormone levels are not associated with the risk of prostate cancer and neither are polymorphisms in various genes encoding the androgen metabolizing enzymes or androgen receptors. Evidence in support of the involvement of androgens in prostate cancer development is derived from clinical trials with 5α-reductase inhibitors, which reduced the risk by approximately 25%. Animal studies using rat models, however, provide clear evidence that testosterone can induce prostate cancer and can act as a strong tumor promoter in concert with genotoxic carcinogens. One such genotoxic factor may be 17β-estradiol, which is generated from testosterone by the aromatase enzyme. Estradiol can be converted to catecholestrogens, which through redox cycling, generate reactive metabolites that can adduct the DNA and potentially lead to mutations. Animal studies and limited human evidence suggest that estrogens can be involved in prostate carcinogenesis by such a genotoxic mechanism. However, how androgens exert their tumor-promoting effect is not clear. It is likely that hormonal and non-hormonal factors as well as genetic and non-genetic (environmental) factors interact in a highly complex and poorly understood manner to determine the risk of prostate cancer.

Oestrogen receptor-alpha polymorphism and risk of fracture: a meta-analysis of 13 studies including 1279 cases and 6069 controls

A meta-analysis was performed to evaluate the effect of oestrogen receptor-alpha (ESR1) gene PvuII polymorphism on fracture risk. It included published data from relevant studies (up to May 2010) identified from Medline, Embase and Current Contents. The 13 included studies contained 1279 fracture cases and 6069 controls. The combined results based on these studies showed no relationship between ESR1 gene PvuII polymorphism and fracture risk. No significant difference in genotype distribution was found when stratifying by race. When stratifying by fracture type, it was found that vertebral fracture cases had a significantly higher frequency of the PvuII pp genotype than controls in five studies (552 cases and 2350 controls). This meta-analysis suggests a modest but statistically significant association between the ESR1 PvuII pp genotype and vertebral fracture.

Mechanisms of prostate cancer initiation and progression

Prostate cancer is a major health problem as it continues to be the most frequently diagnosed cancer in men in the Western world. While improved early detection significantly decreased mortality, prostate cancer still remains the second leading cause of cancer-related death in Western men. Understanding the mechanisms of prostate cancer initiation and progression should have a significant impact on development of novel therapeutic approaches that can help to combat this disease. The recent explosion of novel high-throughput genetic technologies together with studies in animal models and human tissues allowed a comprehensive analysis and functional validation of the molecular changes. This chapter will summarize and discuss recently identified critical genetic and epigenetic changes that drive prostate cancer initiation and progression. These discoveries should help concentrate the efforts of drug development on key pathways and molecules, and finally translate the knowledge that is gained from mechanistic studies into effective treatments.

Polymorphisms in estrogen related genes may modify the protective effect of isoflavones against prostate cancer risk in Japanese men

Soy isoflavones and estrogen related genes may play a major role in the etiology of prostate cancer. This study examined whether the genetic polymorphisms of estrogen receptors (ESR-alpha and ESR-beta) and cytochrome P450 19A1 (CYP19A1) modified the protective effect of isoflavones against prostate cancer. One hundred and eighty cases and 177 controls were selected from three geographic areas of Japan. The odds ratio for more than or equal to 60 versus less than 60 mg/day of the intake of isoflavones was 0.63 (95% confidence interval=0.41-0.96). The TTTA long repeat was significantly associated with an increased risk (odds ratio=1.76, 95% confidence interval=1.15-5.70). The interaction between the polymorphisms and the intake of isoflavones on prostate cancer risk was analyzed by the multifactor dimensionality reduction method. The combination of the TTTA long repeats and the minor alleles of rs10046 in CYP19A1 and rs2077647 in ESR-alpha was a high risk for prostate cancer despite greater than or equal to 60 mg isoflavones/day. The combination of the TTTA short repeat and those homozygous for the major allele of rs10046 in CYP19A1 was low risk despite less than 60 mg isoflavones/day. In conclusion, the findings of this case-control study suggest that the protective effect of isoflavones may differ between the genotypes of estrogen related genes.

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.

Association between estrogen and androgen receptor genes and prostate cancer risk

OBJECTIVE

Prostate cancer (PC) is one of the principal causes of death among men. Steroid hormones are involved in normal prostate growth and carcinogenesis. The purpose of our study was to investigate the effects on PC risk of polymorphisms from three steroid hormone receptor genes: the androgen (AR), and the alpha (ESR1) and beta (ESR2) estrogen receptors.

DESIGN AND METHODS

The study was performed on a Caucasian population of 1045 PC patients and 814 controls. Using a logistic regression model, the different alleles and genotypes from those polymorphisms were analyzed according to case/control status, the tumor aggressiveness, and the age at onset.

RESULTS

A significant association between PC risk and the pooled 4/5, 5/6, and 6/6 genotypes of the GGGA repeat located in the first intron of ESR1 (odds ratio (OR)=3.00, 95% CI=1.32-6.82, P=0.008) was observed. When we stratified the cases, this association was confined to patients with a Gleason score of 2-4 (OR=8.34, 95% CI=2.91-23.91, P<0.0001) or late onset PC (OR=2.91, 95% CI=1.22-6.93, P=0.016). An association between a short AR CAG repeat (less than 17 repeats) was also observed among patients with late onset PC (OR=2.34, 95% CI=1.15-4.76, P=0.019).

CONCLUSIONS

These findings suggest that the GGGA repeat from ESR1 and the CAG repeat from AR may be associated with risk of late onset PC.

Differential expression of genes related to androgen and estrogen metabolism in hereditary versus sporadic prostate cancer

The hereditary predisposition to prostate cancer is rare and accounts for <5% of cases. Except for younger age at diagnosis, no phenotypic features have been clearly associated with hereditary prostate cancer. The aim of the study was to analyze the expression of genes related to androgen and estrogen metabolism in both hereditary and sporadic prostate cancers in patients matched for clinicopathologic features. Tissues were obtained from patients included in a national familial prostate cancer registry. From the 120 cases of hereditary forms suggesting autosomal dominant Mendelian inheritance, 21 patients were treated by radical prostatectomy for whom formalin-fixed tissue was available. Twenty-one sporadic cases were then matched according to age, Gleason score, and pathologic stage. Immunohistochemistry was done on tissue microarray using antibodies directed against androgen receptor (AR), estrogen receptor alpha (ERA), estrogen receptor beta, 5alpha-reductase I and II, aromatase, and the proliferation marker Ki67. The percentage of AR-positive cancer cells was higher in hereditary cancer compared with sporadic cases (P < 0.004). In contrast, the mean number of ERA-positive stromal cells was lower in hereditary versus sporadic cancer (P < 0.03). This differential expression of AR and ERA suggests that a specific pattern of hormone receptors is associated with hereditary predisposition to prostate cancer.

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

Prostate cancer represents a heterogeneous disease with varying degrees of aggressiveness, patterns of metastasis, and response to therapy. It arises from a complex etiology that involves both exogenous (diet, environment, etc.) and endogenous (hormonal and genetic) factors. The present study was performed to explore the role of various genotypes involved in steroid metabolism and synthesis in the causation of prostate cancer. Genetic polymorphism of the ER, CYP17, SRD5A2 (TA repeats), and PSA genes were analyzed in 157 cases of prostate cancer and 340 controls [170 healthy males and 170 patients of benign prostate hyperplasia (BPH)]. Mutant genotypes of ER and CYP17 showed 2- and 3- and 3.5-fold increased risk of prostate cancer, respectively, as compared to BPH and healthy controls. Interaction of mutant (homozygous and heterozygous) alleles of CYP17 with TA (0/0) led to a twofold increased risk of prostate cancer. Risk was more than twofold with the combination of mutant alleles of ER and CYP17. The PSA gene polymorphism did not show any increased risk of prostate cancer. This indicates the role of mutant allele of ER and CYP17 in the development and progression of prostate cancer and rules out any increased risk with PSA polymorphism in the north Indian population.

Hormone receptor-related gene polymorphisms and prostate cancer risk in North Indian population

The purpose of this study was to analyse the frequency and type of mutations in the coding region of androgen receptor (AR) and to determine the role of polymorphisms in the intron 1 of ERalpha, exon 5 of ERbeta, intron 7 of progesterone, exon 7 of the aromatase (CYP19) and exon 9 of VDR genes in the risk of prostate cancer. PCR-RFLP analysis of all above the genes was on 100 prostate cancer patients and an equal number of matching controls. The study also included PCR-SSCP analyses of exons 2-8 of AR gene. The genotype containing -/- allele of ERalpha gene was statistically significant for the risk of prostate cancer pose (OR, 2.70; 95% CI, 1.08-6.70, P = 0.032) Rr genotype of ERbeta gene also have a higher risk (OR, 1.65; 95% CI, 0.52-5.23) for prostate cancer. The Cys allele of CYP19 gene was also associated with statistically significant increased risk of prostate cancer (OR; 2.28, 95% CI, 1.20-4.35, P = 0.012). tt genotype of codon 352 of VDR gene showed an OR of 0.43 for (95% CI, 0.13-1.39) and an OR for Tt genotype was 0.65 (95% CI, 0.36-1.16). Taken together, the results showed that in North Indian population, ERalpha and CYP19 genes may be playing a role in the risk of prostate cancer.

The role of estrogens and estrogen receptors in normal prostate growth and disease

Estrogens have significant direct and indirect effects on prostate gland development and homeostasis and have been long suspected in playing a role in the etiology of prostatic diseases. Direct effects are mediated through prostatic estrogen receptors alpha (ERalpha) and beta (ERbeta) with expression levels changing over time and with disease progression. The present review examines the evidence for a role of estrogens and specific estrogen receptors in prostate growth, differentiation and disease states including prostatitis, benign prostatic hyperplasia (BPH) and cancer and discusses potential therapeutic strategies for growth regulation via these pathways.

Association of RNASEL variants with prostate cancer risk in Hispanic Caucasians and African Americans

PURPOSE

The RNASEL gene at 1q25 has been identified as a hereditary prostate cancer susceptibility gene, but to date, no study has investigated the role of RNASEL variants in Hispanic Caucasian men with prostate cancer.

EXPERIMENTAL DESIGN

Two RNASEL common variants, located at amino acids 462 and 541, were genotyped in non-Hispanic Caucasian, Hispanic Caucasian, and African American prostate cancer cases and controls.

RESULTS

The RNASEL 462 AA genotype was found to increase prostate cancer risk over 4-fold in Hispanic Caucasians [odds ratio (OR), 4.43; 95% confidence interval (95% CI), 1.68-11.68; P = 0.003] and over 10-fold in African Americans (OR, 10.41; 95% CI, 2.62-41.40; P = 0.001) when compared with the GG genotype. Analysis of the RNASEL 541 variant showed that Hispanic Caucasian patients with the GG genotype had a statistically significant increase in their risk for developing prostate cancer when compared with the TT and GT genotypes (OR, 1.91; 95% CI, 1.16-3.14; P = 0.01). A common G-T haplotype for the combination of the RNASEL 462 and 541 variants was found to occur more frequently in controls compared with cases in African Americans (P = 0.04) but not in non-Hispanic Caucasians or Hispanic Caucasians.

CONCLUSIONS

This is the first study that investigates the association of prostate cancer risk with RNASEL variants in Hispanic men. Our data support the role of RNASEL as a predisposition gene for prostate cancer and showed a significant association between the RNASEL 462 variant and prostate cancer risk in African Americans and Hispanic Caucasians.

Genetics and pharmacogenetics of estrogen response

Estrogens are a steroid hormone group distributed widely in animals and human beings. Estrogens diffuse across cell phospholipidic membranes and interact with estrogen receptors. Their highest concentration is found in target tissues with reproductive function (breast, ovary, vagina and uterus). High estrogen levels are usually associated with tumor onset and progression, while loss of estrogen or its receptor(s) contributes to development and/or progression of various diseases (osteoporosis, neurodegenerative disease and cardiovascular disease). Despite the numerous efforts to highlight estrogen's mechanism of action, recent discoveries showed an unexpected degree of complexity of estrogenic response.

Estrogen receptor alpha-351 XbaI*G and -397 PvuII*C-related genotypes and alleles are associated with higher susceptibilities of endometriosis and leiomyoma

Endometriosis and leiomyoma are both common estrogen-related gynaecological diseases. We aimed to elucidate the association of estrogen receptor alpha (ERalpha)-351 A>G (XbaI) and -397 T>C (PvuII) gene polymorphisms with endometriosis and leiomyoma. Women were divided into three groups: (i) severe endometriosis (n = 112), (ii) leiomyoma (n = 106) and (iii) normal controls (n = 110). Genomic DNA was obtained from peripheral leukocytes. ERalpha-351 A/G XbaI and -397 T/C PvuII polymorphisms were assayed by the method of PCR and restriction fragment length polymorphism (RFLP). Genotypes and allelic frequencies in each group were compared. The genotype/allele frequencies of ERalpha-351 and -397 polymorphisms in endometriosis or leiomyoma groups were different from those of normal controls. ERalpha mutant-related genotypes/alleles (-351G and -397C) presented higher percentages in the endometriosis/leiomyoma population compared with normal controls. Proportions of ERalpha-351 AA/AG/GG genotypes and A/G alleles in each group were (i) 26.8/57.1/16.1 and 55.4/44.6%; (ii) 19.8/52.8/27.4 and 46.2/53.8% and (iii) 33.6/64.6/1.8 and 65.9/34.1%. Proportions of ERalpha-397 TT/TC/CC genotypes and T/C alleles in each group were (i) 24.1/60.7/15.2 and 54.5/45.5%; (ii) 23.6/70.8/5.6 and 59/41% and (iii) 54.5/40/5.5 and 74.5/25.5%. We concluded that ERalpha-351 XbaI*G- and -397 PvuII*C-related genotypes/alleles were correlated with higher susceptibilities of endometriosis or leiomyoma, which might be associated with related pathogeneses.

A review of the ethnic differences in breast cancer

Women of African descent have a lower incidence of breast cancer than their white counterparts; however, the overall age-adjusted breast cancer mortality rates are higher. They also present at a younger age, and have more advanced disease that exhibits poor prognostic features including significantly larger tumors of higher grade, higher rates of estrogen receptor and progesterone receptor negativity and a higher rate of p53 mutations and HRAS1 proto-oncogene expression, all of which confer a poor prognosis. While there are many possible contributory factors to the discrepancies in outcome in women of African descent, there is no satisfactory explanation as to why women of African origin tend to present at a younger age with hormone receptor-negative tumors and more adverse prognostic features.