Polymorphisms of the genes encoding the GSTM1, GSTT1 and GSTP1 in Korean women: no association with endometriosis

Emerging hallmarks of endometriosis metabolism: A promising target for the treatment of endometriosis

Endometriosis, characterized by ectopic endometrium growth in the extrauterine environment, is one of the most notable diseases of the female reproductive system. Worldwide, endometriosis affects nearly 10 % of women in their reproductive years and causes a significant decline in quality of life. Despite extensive investigations of endometriosis over the past years, the mechanisms of endometriosis pathogenesis remain unclear. In recent years, metabolic factors have increasingly been considered factors in endometriosis. There is compelling evidence regarding the progress of endometriosis in the context of severe metabolic dysfunction. Hence, the curative strategies and ongoing attempts to conquer endometriosis might start with metabolic pathways. This review focuses on metabolic mechanisms and summarizes current research progress. These findings provide valuable information for the non-intrusive diagnosis of the disease and may contribute to the understanding of the pathogenesis of endometriosis.

Polymorphisms and endometriosis: a systematic review and meta-analyses

BACKGROUND

Endometriosis is an estrogen-dependent gynecological disorder that affects at least 10% of women of reproductive age. It may lead to infertility and non-specific symptoms such as chronic pelvic pain. Endometriosis screening and diagnosis are difficult and time-consuming. Late diagnosis (with a delay ranging from 3.3 to 10.7 years) is a major problem and may contribute to disease progression and a worse response to treatment once initiated. Efficient screening tests might reduce this diagnostic delay. As endometriosis is presumed to be a complex disease with several genetic and non-genetic pathogenic factors, many researchers have sought to identify polymorphisms that predispose to this condition.

OBJECTIVE AND RATIONALE

We performed a systematic review and meta-analysis of the most regularly reported polymorphisms in order to identify those that might predispose to endometriosis and might thus be of value in screening.

SEARCH METHODS

The MEDLINE database was searched for English-language publications on DNA polymorphisms in endometriosis, with no date restriction. The PubTator text mining tool was used to extract gene names from the selected publications' abstracts. We only selected polymorphisms reported by at least three studies, having applied strict inclusion and exclusion criteria to their control populations. No stratification based on ethnicity was performed. All steps were carried out according to PRISMA guidelines.

OUTCOMES

The initial selection of 395 publications cited 242 different genes. Sixty-two genes (corresponding to 265 different polymorphisms) were cited at least in three publications. After the application of our other selection criteria (an original case-control study of endometriosis, a reported association between endometriosis and at least one polymorphism, data on women of reproductive age and a diagnosis of endometriosis in the cases established by surgery and/or MRI and confirmed by histology), 28 polymorphisms were eligible for meta-analysis. Only five of the 28 polymorphisms were found to be significantly associated with endometriosis: interferon gamma (IFNG) (CA) repeat, glutathione S-transferase mu 1 (GSTM1) null genotype, glutathione S-transferase pi 1 (GSTP1) rs1695 and wingless-type MMTV integration site family member 4 (WNT4) rs16826658 and rs2235529. Six others showed a significant trend towards an association: progesterone receptor (PGR) PROGINS, interCellular adhesion molecule 1 (ICAM1) rs1799969, aryl-hydrocarbon receptor repressor (AHRR) rs2292596, cytochrome family 17 subfamily A polypeptide 1 (CYP17A1) rs743572, CYP2C19 rs4244285 and peroxisome proliferator-activated receptor gamma (PPARG) rs1801282), and 12 showed a significant trend towards the lack of an association: tumor necrosis factor (TNF) rs1799964, interleukin 6 (IL6) rs1800796, transforming growth factor beta 1 (TGFB1) rs1800469, estrogen receptor 1 (ESR1) rs2234693, PGR rs10895068, FSH receptor (FSHR) rs6166, ICAM1 rs5498, CYP1A1 rs4646903, CYP19A1 rs10046, tumor protein 53 (TP53) rs1042522, X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) rs25487 and serpin peptidase inhibitor clade E member 1 (SERPINE1) rs1799889; however, for the 18 polymorphisms identified in the latter two groups, further studies of the potential association with the endometriosis risk are needed. The remaining five of the 28 polymorphisms were not associated with endometriosis: glutathione S-transferase theta 1 (GSTT1) null genotype, vascular endothelial growth factor alpha (VEGFA) rs699947, rs833061, rs2010963 and rs3025039.

WIDER IMPLICATIONS

By carefully taking account of how the control populations were defined, we identified polymorphisms that might be candidates for use in endometriosis screening and polymorphisms not associated with endometriosis. This might constitute the first step towards identifying polymorphism combinations that predispose to endometriosis (IFNG (CA) repeat, GSTM1 null genotype, GSTP1 rs1695, WNT4 rs16826658 and WNT4 rs2235529) in a large cohort of patients with well-defined inclusion criteria. In turn, these results might improve the diagnosis of endometriosis in primary care. Lastly, our present findings may enable a better understanding of endometriosis and improve the management of patients with this disease.

Association of Genetic Polymorphisms in GSTP1, GSTM1, and GSTT1 Genes with Vesicoureteral Reflux Susceptibility in the Children of Southeast Iran

Background:

Vesicoureteral reflux (VUR) disease is the most common type of urinary tract anomalies in children. Genetic risk factors may be associated with the etiology of VUR. The role of the Glutathione S-transferases (GSTs) as multifunctional enzymes is cellular oxidative stress handling. This is the first study aimed at evaluating the relative risk of GSTP1, GSTM1, and GSTT1 polymorphisms in VUR susceptibility in children and provides new important insights into the genetics of affected children.

Methods:

The study was done in 2013 in Sistan and Baluchestan University, eastern Iran. Genotyping of three GSTP1, GSTM1, and GSTT1 genes were determined using the multiplex polymerase chain reaction assay in 216 reactions for 72 VUR children and 312 reactions for 104 healthy controls.

Results:

The presence of GSTT1 deletion was associated with high risk of VUR in children, whereas GSTP1 and GSTM1 genotypes did not show the same effect. Furthermore, the combination of GSTT1/GSTM1 and GSTT1/ GSTP1 genotypes showed a significant influence on lower risk of VUR in children.

Conclusion:

Deletion of GSTT1 functional gene is a genetic risk factor causing VUR in children. Interestingly, the combination of GSTM1 and GSTP1 null genotypes with GSTT1 has shown a protective role against risk of GSTT1 deletion.

Association of GSTP1, GSTT1 and GSTM1 Gene Variants with Coronary Artery Disease in Iranian Population: A Case-Control Study

Background

Coronary artery disease (CAD) is a multifactorial disease that may be caused by the interaction between environmental and genetic risk factors. Glutathione S-transferases (GSTs) are known to participate in detoxification and metabolism of a wide range of xenobiotic compounds and oxidative stress products. Considering the interaction between environmental and genetic factors in CAD, we investigated the genetic polymorphisms of GSTM1, GSTT1, and GSTP1 in the Iranian population.

Patients and Methods

Two hundred and forty-four CAD cases and 281 healthy controls were studied. The genotype of GSTM1, GSTT1, and GSTP1 genes was determined by multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) techniques. Multivariable logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CI). Multifactor dimensionality reduction (MDR) analysis was also carried out to analyze the gene–gene and gene–environment interaction.

Results

The genotype and allele distribution of the three variations were not significantly different between CAD patients and controls (p > 0.05). The subgroup analysis revealed no significant gene–gene interactions or gene–gene combination effects linked to CAD susceptibility. However, MDR analysis selected the GSTM, GSTT pairwise and three genes combination models associated with the susceptibility to CAD. In addition, its result revealed that smoking in combination with GSTM1 (two-way) and GSTT, GSTP (three-way) genes might increase the risk of CAD. Furthermore, a significant interaction between GSTT1-null polymorphism and dyslipidemia was found in multivariable logistic regression analyses in the gene–environmental interactions on CAD risk.

Conclusion

Our results suggest that the GSTM1, GSTT1 and GSTP1 genetic variations are not directly associated with the susceptibility to CAD in Iranian patients. Due to MDR results, there might be a non-linear association between interactions of two or three genes and smoking with CAD. There is also an association between CAD risk factors and GST variations, which requires supplementary confirmation with larger sample sizes.

Epidemiologic Factors Associated with Endometriosis in East Asia

Aim

With a perplexing pathogenesis and an incidence rate of approximately 10% among women of reproductive age, endometriosis affects more women in Asia than in any other continent in the world. This paper reviews the available data on the epidemiology and risk factors associated with endometriosis in East Asia.

Methods

Included studies were published between January 2000 and December 2016. Articles were required to include East Asian patients with a diagnosis of endometriosis and to study epidemiology, such as the prevalence and/or incidence, associated with inherited, environmental, and/or lifestyle factors. A total of 65 candidate articles were retrieved and 22 were included in the final review.

Results

Only one study provided an estimate of prevalence (6.8%). Short menstrual cycle, family history of endometriosis, and some genetic polymorphisms are associated with the risk of developing endometriosis. Smoking, lower body mass index, and lower parity associated with increased risk of endometriosis were suggested as modifiable factors. Limitations of this study include the poor quality of data identified, and the language barriers behind the study retrieval.

Conclusions

Data on the epidemiology of endometriosis in the East Asian populations are limited. The available data that examine potential genetic factors do not unveil whether such factors directly contribute to the increased risk of endometriosis. Further extensive studies on endometriosis in Asian women are required to improve the management of this disease.

Identification of genes differentially expressed in menstrual breakdown and repair

STUDY QUESTION

Does the changing molecular profile of the endometrium during menstruation correlate with the histological profile of menstruation.

SUMMARY ANSWER

We identified several genes not previously associated with menstruation; on Day 2 of menstruation (early-menstruation), processes related to inflammation are predominantly up-regulated and on Day 4 (late-menstruation), the endometrium is predominantly repairing and regenerating.

WHAT IS KNOWN ALREADY

Menstruation is induced by progesterone withdrawal at the end of the menstrual cycle and involves endometrial tissue breakdown, regeneration and repair. Perturbations in the regulation of menstruation may result in menstrual disorders including abnormal uterine bleeding.

STUDY DESIGN, SIZE DURATION

Endometrial samples were collected by Pipelle biopsy on Days 2 (n = 9), 3 (n = 9) or 4 (n = 6) of menstruation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RNA was extracted from endometrial biopsies and analysed by genome wide expression Illumina Sentrix Human HT12 arrays. Data were analysed using 'Remove Unwanted Variation-inverse (RUV-inv)'. Ingenuity pathway analysis (IPA) and the Database for Annotation, Visualization and Integrated Discovery (DAVID) v6.7 were used to identify canonical pathways, upstream regulators and functional gene clusters enriched between Days 2, 3 and 4 of menstruation. Selected individual genes were validated by quantitative PCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, 1753 genes were differentially expressed in one or more comparisons. Significant canonical pathways, gene clusters and upstream regulators enriched during menstrual bleeding included those associated with immune cell trafficking, inflammation, cell cycle regulation, extracellular remodelling and the complement and coagulation cascade. We provide the first evidence for a role for glutathione-mediated detoxification (glutathione-S-transferase mu 1 and 2; GSTM1 and GSTM2) during menstruation. The largest number of differentially expressed genes was between Days 2 and 4 of menstruation (n = 1176). We identified several genes not previously associated with menstruation including lipopolysaccharide binding protein, serpin peptidase inhibitor, clade B (ovalbumin), member 3 (SERPINB3) and -4 (SERPINB4), interleukin-17C (IL17C), V-set domain containing T-cell activation inhibitor 1 (VTCN1), proliferating cell nuclear antigen factor (KIAA0101/PAF), trefoil factor 3 (TFF3), laminin alpha 2 (LAMA2) and serine peptidase inhibitor, Kazal type 1 (SPINK1). Genes related to inflammatory processes were up-regulated on Day 2 (early-menstruation), and those associated with endometrial repair and regeneration were up-regulated on Day 4 (late-menstruation).

LIMITATIONS, REASONS FOR CAUTION

Participants presented with a variety of endometrial pathologies related to bleeding status and other menstrual characteristics. These variations may also have influenced the menstrual process.

WIDER IMPLICATIONS OF THE FINDINGS

The temporal molecular profile of menstruation presented in this study identifies a number of genes not previously associated with the menstrual process. Our findings provide valuable insight into the menstrual process and may present novel targets for therapeutic intervention in cases of endometrial dysfunction.

LARGE SCALE DATA

All microarray data have been deposited in the public data repository Gene Expression Omnibus (GSE86003).

STUDY FUNDING AND COMPETING INTERESTS

Funding for this work was provided by a National Health and Medical Research Council of Australia (NHMRC) Project Grant APP1008553 to M.H., P.R. and J.G. M.H. is supported by an NHMRC Practitioner Fellowship. P.P. is supported by a NHMRC Early Career Fellowship. The authors have no conflict of interest to declare.

Association study between GSTT1 and GSTM1 polymorphisms and risk of preeclampsia in Chinese population

CONTEXT AND OBJECTIVE

Preeclampsia is a pregnancy-specific disorder associated with oxidative stress. The glutathione S-transferases (GST) are a group of enzymes that protect cells from oxidative stress. Functional genetic polymorphisms of GST genes (GSTT1, GSTM1) have previously been reported. The aim of this study was to investigate the association of GST gene polymorphisms with the risk of preeclampsia in Chinese subjects.

STUDY DESIGN

The case-control population consists of 525 subjects. The genotyping of the GSTT1 and GSTM1 polymorphisms was carried out on genomic DNA using the multiplex polymerase chain reaction (PCR). We calculated odds ratios (ORs), adjusted for the confounding variables, to estimate the association between gene polymorphisms and preeclampsia.

RESULTS

The GSTT1 null genotype was found to be protective from the development of preeclampsia (odds ratios 0.645, 95% confidence interval 0.421-0.989; P=0.044). Further analysis showed that a combination of deletion genotypes of the GSTT1 and GSTM1 genes conferred an even lower risk of preeclampsia (OR=0.470, 95%CI=0.255-0.866; P=0.015). There is no relationship between the GSTT1 and GSTM1 gene polymorphisms and blood pressure levels in pregnant women with and without preeclampsia.

CONCLUSION

Our data suggest that a GSTT1 null polymorphism might be associated with decreased risk for preeclampsia in the Chinese population, and that this risk decreases with the combination of both GSTT1 and GSTM1 null polymorphisms.

Association between glutathione S-transferase M1/T1 gene polymorphisms and susceptibility to endometriosis: A systematic review and meta-analysis

Endometriosis is a polygenic/multifactorial disease caused by interactions between multiple genes and the environment. Findings from studies evaluating the association between the glutathione S-transferase (GST) M1/T1 null genotype and susceptibility to endometriosis are inconsistent. This meta-analysis updated and reevaluated the possible associations between GSTM1, GSTT1 and combined GSTM1/GSTT1 (null genotype versus wild-type) gene polymorphisms and susceptibility to endometriosis. The PubMed, Embase and Chinese BioMedical Literature databases and Google Scholar were searched for case-control genetic association studies on GSTM1/GSTT1 (null genotype versus wild-type) gene polymorphisms and endometriosis in comparison with non-endometriosis or healthy controls. Fixed-effect and random-effect meta-analytical techniques were conducted for the outcome measure and subgroup analyses. The meta-analysis demonstrated significant associations between the GSTM1 [odds ratio (OR)=1.56; 95% confidence interval (CI): 1.25–1.95; P<0.0001), GSTT1 (OR=1.31; 95% CI: 1.02–1.68; P=0.037) and GSTM1/GSTT1 (OR=1.68; 95% CI: 1.29–2.17; P<0.0001) null genotypes and increased risk for endometriosis. The results suggest that the GSTM1, GSTT1, and combined GSTM1/GSTT1 null genotypes increase susceptibility to endometriosis. Additional well-designed studies and precise analyses are warranted to confirm these findings.

Impact of null genotypes of GSTT1 and GSTM1 with uterine leiomyoma risk in Iranian population

AIM

Few studies have investigated the role of the GSTM1 and GSTT1 genes in uterine leiomyoma. Therefore, in the current study the distribution of these genotypes in Iranian women and susceptibility to uterine leiomyoma was investigated.

METHODS

Blood samples of 50 patients with uterine leiomyoma and 50 healthy individual controls were collected in this cross-sectional study. Genomic DNA was extracted, and subsequently GSTM1 and GSTT1 null genotypes were detected by the Gap-polymerase chain reaction method.

RESULTS

A total of 42% of patients appeared to lack GSTM1 enzyme activity due to the presence of an extended deletion (GSTM1 0/0 genotype), compared with 18% in a control group (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.35-9.37; P < 0.010). In addition, the prevalence of the GSTT1 null genotype in patients was higher than that in the control group (42% to 14%, P < 0.009). Also, it was shown that individuals with both null genotypes (-/-) had a 19.23-fold higher risk of developing the disease in comparison to people who showed both present genotypes (+/+). (P = 0.007; 95%CI, 2.20-167.41). Besides, it was observed that at least one null genotype increases the risk of myoma to 2.6 compared to the both present genotype (P-value < 0.03, 95%CI, 1.05-6.82).

CONCLUSION

To our knowledge, this is first significant correlation between risk of uterine leiomyoma and null GSTM1 and GSTT1 genotypes among Iranian patients. Our data support the involvement of GSTM1 and GSTT1 in uterine leiomyoma liability, and especially its role as a genetic factor in the occurrence of this disease.

Polymorphisms of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) and endometriosis risk: a meta-analysis

Published data on the association between the glutathione S-transferases (GSTs) gene polymorphisms and endometriosis risk are inconclusive. We performed a meta-analysis to clarify the association of GSTM1 and GSTT1 polymorphisms and endometriosis risk. A comprehensive search was conducted to examine all the eligible studies of GSTM1 and GSTT1 polymorphisms and endometriosis risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. A total of 18 case-control studies were included in the meta-analysis of GSTM1 (2593 cases and 2732 controls) and GSTT1 (2520 cases and 2508 controls) genotypes. The overall results showed that the GSTM1 null genotype was related to an increased risk of endometriosis (OR=1.55, 95% CI=1.38-1.73). Similarly, for GSTT1 null polymorphism, moderate significantly increased risk was found (OR=1.30, 95% CI=1.13-1.50). In the subgroup analysis by ethnicity, significantly increased risks were also found among Caucasians and Asians for null GSTM1 genotype, and Asians for null GSTT1 genotype, but no correlation was noted in Caucasian populations for GSTT1 polymorphism. This meta-analysis provides strong evidence that the GSTM1 and GSTT1 polymorphisms are associated with the development of endometriosis.

Null genotypes of GSTM1 and GSTT1 and endometriosis risk: a meta-analysis of 25 case-control studies

Endometriosis is one of the most frequent benign gynecological disorders. Numerous studies have shown an association between GSTM1 and/or GSTT1 polymorphisms and endometriosis susceptibility. However, these associations remain inconclusive. To derive a more precise estimation, we conducted a comprehensive search to identify all existing studies and then performed a meta-analysis. Electronic literature searches of the PubMed, Chinese Biomedical, and China National Knowledge Infrastructure databases were performed up to December 2013. GSTM1-, GSTT1-, and dual-null genotypes were analyzed independently, and pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated by comparing the null genotype with other genotypes using the random-effects or fixed-effects model. Twenty-five and 16 independent studies on GSTM1 and GSTT1 polymorphisms, respectively, and five GSTM1-GSTT1 interaction analyses were identified and included in this meta-analysis. Both GSTM1- and GSTT1-null genotypes increased risk of endometriosis (OR = 1.54, 95% CI: 1.30-1.83, P<0.001; OR = 1.41, 95% CI: 1.10-1.82, P = 0.007; respectively). Moreover, we found a significant positive association between the dual null genotype GSTM1-GSTT1 and endometriosis susceptibility (OR = 1.33, 95% CI: 1.03-1.72, P = 0.027). This meta-analysis provides evidence that null genotypes of GSTM1 and/or GSTT1 contribute to risk of endometriosis. Further investigations are required to confirm these findings.

Association between susceptibility to advanced pelvic organ prolapse and glutathione S-transferase P1 Ile105Val polymorphism

OBJECTIVE

Oxidative stress is associated with the pathogenesis of pelvic organ prolapse (POP). Because glutathione S-transferases (GSTs) are the major detoxification enzymes which protect cells against oxidative stress, genetic variations in the GST gene may modulate the risk of POP. This study aimed to determine the association between advanced POP and the polymorphisms of GSTM1, GSTT1 and GSTP1 (rs1695).

STUDY DESIGN

This is a hospital-based case-control study. The POP group consisted of 189 women diagnosed with POP stage III or IV, and the control group consisted of 156 postmenopausal women with POP stage 0 or I. The GSTM1 and GSTT1 null mutations were detected by multiplex PCR, and the GSTP1 Ile105Val polymorphism was genotyped by real-time PCR analysis using a TaqMan assay.

RESULTS

There was no significant association between the GSTM1 and GSTT1 null mutations and advanced POP (p>0.05). The distribution of the GSTP1 Ile105Val genotypes, however, was significantly different between the POP and control groups (AA/AG/GG rates=74.1%/25.9%/0% vs. 64.1%/32.1%/3.8%, p=0.008), and the G allele frequency was significantly lower in the POP group than in the control group (13.0% vs. 19.9%, p=0.014). Women with the non-AA genotype had a 0.63-fold lower risk of developing advanced POP than women with the AA genotype (95% CI, 0.39-0.99), and women with the G allele had a 0.60-fold lower risk of advanced POP than women with the A allele (95% CI, 0.40-0.90).

CONCLUSIONS

The GSTP1 Ile105Val polymorphism is a protective factor against advanced POP.

Genetic association studies in female reproduction: from candidate-gene approaches to genome-wide mapping

Many genetic association studies have been performed to investigate disorders of female reproduction, such as polycystic ovary syndrome, premature ovarian failure and endometriosis. These disorders typically manifest heterogeneously, and their pathogeneses are influenced by polygenic and environmental factors. Researchers evaluating these genetic associations have chosen candidate genes related to hormone action, steroid biosynthesis, inflammatory cytokines and autoimmune factors. Several of these genes have yielded statistically significant associations with female reproductive disorders; however, few associations have been robust and reproducible. Whole-genome association studies generate more reliable and unbiased results and represent a breakthrough in genetic studies of female reproduction. Nevertheless, to date only a very small fraction of the overall heritability has been identified and so further studies are needed.

Association of genetic polymorphisms of glutathione-S-transferase genes (GSTT1, GSTM1, and GSTP1) and susceptibility to nonalcoholic fatty liver disease in Zahedan, Southeast Iran

Oxidative damage is thought to play a pivotal role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Glutathione-S-transferases (GSTs) are involved in cell protection against oxidative stress. We examined whether GSTM1, GSTT1, and GSTP1 polymorphisms are associated with NAFLD in a sample of the Iranian population. The current case-control study included 83 patients with NAFLD and 93 healthy subjects. The GSTM1 and GSTT1 polymorphisms were analyzed by multiplex polymerase chain reaction (PCR). The GSTP1 polymorphism was detected by tetra amplification refractory mutation system-PCR assay. The GSTM1-null genotype was significantly associated with the development of NAFLD (odds ratios [OR]=2.171, 95% confidence intervals [CI]=1.188-3.970, p=0.015). The GSTP1 Val allele was shown to be a risk factor for NAFLD (OR=1.739, 95% CI=1.089-2.777, p=0.024). The GSTT1 polymorphism was not significantly different between control and patient groups (p=0.221). This study showed that GSTM1 and GSTP1, but not GSTT1, genetic polymorphisms are associated with NAFLD in a sample of the Iranian population, and may be used to determine the risk of development of NAFLD.

Estrogen receptor 1, glutathione S-transferase P1, glutathione S-transferase M1, and glutathione S-transferase T1 genes with dysmenorrhea in Korean female adolescents

BACKGROUND

Dysmenorrhea is the most common gynecologic complaint among adolescent females. We investigated the association between genetic polymorphisms and dysmenorrhea.

METHODS

A total of 202 postmenarcheal Korean female adolescents 16-17 yr old participated in this study. Genotyping for glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1), glutathione S-transferase pi 1 (GSTP1), and estrogen receptor 1 (ESR1) was performed using PCR-based methods.

RESULTS

The PP+Pp genotype of the ESR1 gene was more frequent than pp genotypes in subjects with dysmenorrhea than in subjects without dysmenorrhea (odds ratio=2.440; 95% confidence interval, 1.036-5.753; P=0.040) using an unadjusted univariate logistic regression analysis. The relationship between dysmenorrhea and ESR1 gene polymorphisms remained significant after adjustment for premenstrual syndrome, years elapsed after menarche, and family history of dysmenorrhea. No significant difference was observed between subjects with dysmenorrhea and subjects without dysmenorrhea for polymorphisms of GSTM1, GSTT1, and GSTP1 genes.

CONCLUSIONS

Our results suggest that ESR1 gene polymorphisms may be associated with dysmenorrhea.

Association between phthalate exposure and glutathione S-transferase M1 polymorphism in adenomyosis, leiomyoma and endometriosis

BACKGROUND

Phthalates are known to have estrogenic effects in cell models and experimental animals. However, the evidence regarding the effects of phthalates on human reproduction is still limited. We conducted a case-control study to determine whether estrogen-dependent diseases are associated with phthalate exposure and how the glutathione S-transferase M1 (GSTM1; a major detoxification enzyme) genotype modulates the risk.

METHODS

We recruited subjects who underwent laparotomy and had pathologic confirmation of endometriosis (EN) (n = 28), adenomyosis (AD) (n = 16) and leiomyoma (LEI) (n = 36) from the Department of Obstetrics and Gynecology at a medical center in Taiwan between 2005 and 2007. Controls (n = 29) were patients without any of the three aforementioned gynecologic conditions. Urine samples were collected before surgery and analyzed for seven phthalate metabolites using liquid chromatography-tandem mass spectrometry. Peripheral lymphocytes were used for GSTM1 genotype determination.

RESULTS

Patients with LEIs had significantly higher levels of total urinary mono-ethylhexyl phthalate (SigmaMEHP; 52.1 versus 18.9 microg/g creatinine, P < 0.05) than the controls, whereas patients with EN had an increased level of urinary mono-n-butyl phthalate (94.1 versus 58.0 microg/g creatinine, P < 0.05). Subjects with GSTM1 null genotype had significantly increased odds for AD relative to those with GSTM1 wild genotype [odds ratio (OR) = 5.30; 95% CI, 1.22-23.1], even after adjustment for age and phthalate exposure. Subjects who carried the GSTM1 null genotype and had a high urinary level of SigmaMEHP showed a significantly increased risk for AD (OR = 10.4; 95% CI, 1.26-85.0) and LEIs (OR = 5.93; 95% CI, 1.10-31.9) after adjustment for age, compared with those with GSTM1 wild-type and low urinary level of SigmaMEHP.

CONCLUSIONS

These results suggest that both GSTM1 null and phthalate exposure are associated with AD and LEI. Larger studies are warranted to investigate potential interaction between GSTM1 null and phthalate exposure in the etiology of estrogen-dependent gynecologic conditions.

No association between the GSTP1 exon 5 polymorphism and susceptibility to advanced stage endometriosis in the Korean population

PROBLEM

To investigate whether the glutathione-S-transferase P1 (GSTP1) exon 5 polymorphism is associated with susceptibility to advanced stage endometriosis in Korean women.

METHOD OF STUDY

Case-control study in a collective of 260 patients and 164 controls. Genotyping of the GSTP1 exon 5 polymorphism was performed by using real-time TaqMan PCR assay.

RESULTS

The genotype distribution of the GSTP1 exon 5 polymorphism in the endometriosis group was not significantly different from that of the control group (AA/AG/GG rates were 64.2%/32.7%/3.1% and 65.2%/31.7%/3.0% for the endometriosis and control groups, respectively, P = 0.977). Further subgroup analysis according to either stage or bilaterality of ovarian endometrioma also found no significant difference in the genotype distribution between any of the endometriosis subgroups and the control group.

CONCLUSION

These findings suggest that the GSTP1 exon 5 polymorphism is not a major determinant of the development of advanced stage endometriosis in the Korean population.

Association between glutathione S-transferase polymorphisms and triglycerides and HDL-cholesterol

OBJECTIVE

Null genotypes of glutathione S-transferase (GSTs) exhibit absence of enzymatic activity and are hypothesized to modulate an increased risk of developing cardiovascular disease. The aim of this study was to identify the potential association between GSTM1 and GSTT1 deleted polymorphisms with cardiovascular risk factors and coronary atherosclerosis in two independent urban populations.

METHODS AND RESULTS

Genotype distribution of GSTM1 and GSTT1 deleted polymorphism were examined in a sample of 1577 individuals from the general population and a replication sample of 871 individuals submitted to coronary angiography. Triglycerides, HDL-cholesterol and the triglycerides/HDL ratio were significantly associated with a double-deleted genotype in individuals from the general population. These findings were replicated in a second, independent, population of individuals submitted to coronary angiography. In addition, coronary artery disease severity was also associated with GSTs genotypes and the risk conferred from GSTs genotype was mainly due to triglycerides/HDL ratio information.

CONCLUSIONS

The data suggest that the presence of a double deletion genotypes of the GSTM1 and GSTT1 genes is associated with hypertriglyceridemia and low HDL-cholesterol levels in humans. These novel findings may provide a new unexplored link between lipid metabolism and GST homeostasis.

Functional genetic polymorphisms and female reproductive disorders: part II--endometriosis

BACKGROUND

Endometriosis has a strong genetic component, and numerous genetic studies have been reported.

METHODS

We have systematically reviewed these studies and included 114 in our final selection.

RESULTS

We found no consistent evidence linking endometriosis with specific polymorphisms in genes encoding inflammatory mediators, proteins involved in sex steroid metabolism, vascular function and tissue remodelling. Although a number of polymorphisms have been associated with endometriosis in selected populations, the associations have not been independently confirmed, either because only single studies were carried out on these markers/genes or because other studies reported no association. The most solid evidence linking specific polymorphisms to endometriosis came from studies investigating glutathione-S-transferase, a phase II detoxification enzyme. Carriage of the GSTT1 null deletion variant showed consistent association with endometriosis with a 29% increased risk; however, it cannot be excluded that this result was due to publication bias, and this association should be independently confirmed in large-scale, well-designed case–control studies.

CONCLUSIONS

The evidence of an association between genetic polymorphisms and endometriosis is weak. Carriage of the GSTT1 null deletion may moderately increase the risk of this disease. We suggest that the methodology of association studies should be improved in order to identify and validate associations in endometriosis.

Haplotype analysis of the matrix metalloproteinase-9 gene associated with advanced-stage endometriosis

OBJECTIVE

To investigate whether the -1562C>T, R279Q, P574R, and R668Q polymorphisms of the matrix metalloproteinase-9 (MMP-9) gene are related to endometriosis.

DESIGN

Case-control study.

SETTING

University-based hospital in Korea.

PATIENT(S)

Patients with endometriosis stage III/IV (n = 225) who underwent pelvic surgery and controls (n = 198) with no endometriosis in a Korean population.

INTERVENTION(S)

Peripheral blood samples were collected by venipuncture.

MAIN OUTCOME MEASURE(S)

Frequencies of genotypes and haplotypes were compared with the risk of endometriosis including -1562C>T, R279Q, P574R, and R668Q polymorphisms of MMP-9.

RESULT(S)

In the two-locus haplotype analyses using the four single nucleotide polymorphisms (SNPs), an increase in the distribution of the R279Q/P574R (2678G>A/4859C>G) (AC haplotype: odds ratio [OR] = 3.180, 95% confidence interval [CI] = 1.956-5.170; GG haplotype: OR = 4.374, 95% CI = 2.376-8.053) and -1562C>T/R668Q (-1562C>T/5546G>A) (CA haplotype: OR = 3.280, 95% CI = 1.406-7.653) haplotypes was significantly associated with endometriosis. By contrast, the risk of endometriosis was not associated with the individual SNPs studied.

CONCLUSION(S)

These findings suggest that haplotype analysis was more informative than SNP analysis. The haplotypes in the MMP-9 gene may correlate with the progression of endometriosis, and further study of these variations might improve our understanding of the pathogenesis of endometriosis.

Endometriosis and Genetic Polymorphisms

Endometriosis is a benign gynecological disease with an unclear pathophysiology characterized by ectopic endometrium causing endometrium-like inflammatory lesions outside the uterine cavity. Recently, a number of studies have investigated genetic polymorphisms as a possible factor contributing to the development of endometriosis. In this review, we have summarized current data regarding genes with nucleotide polymorphisms investigated with regard to endometriosis. We searched PubMed for publications on endometriosis and polymorphism and found 108 publications between January 1979 and September 2005. These were classified according to the type of genetic polymorphism investigated and whether the result favored or did not favor association with endometriosis. We found a strikingly large amount of conflicting results. About 50% of the reviewed studies demonstrated positive correlations between different polymorphisms and endometriosis. This relation is most clearly seen in groups 1 (cytokines and inflammation), 2 (steroid-synthesizing enzymes and detoxifying enzymes and receptors), 4 (estradiol metabolism), 5 (other enzymes and metabolic systems), and 7 (adhesion molecules and matrix enzymes). Group 8 (apoptosis, cellcycle regulation, and oncogenes) seemed to be negatively correlated with the disease, whereas group 3 (hormone receptors), 6 (growth factor systems), and especially 9 (human leukocyte antigen system components) showed a relatively strong correlation. The review indicates that polymorphisms may have a limited value in assessing possible development of endometriosis.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall the complexity of attempting to link endometriosis to single nucleotide polymorphisms (SNPs), explain that the literature is varied on results and recommendations and is population specific, and state that there are some SNP relationships that are clinically stronger than others.

Polymorphisms and haplotypes of the gene encoding the estrogen-metabolizing CYP19 gene in Korean women: no association with advanced-stage endometriosis

A variety of factors affect the development of endometriosis, including hormonal status and genetic factors. The growth of endometriosis is stimulated by local estrogen production in conjunction with circulating estrogen. The CYP19 gene encodes a steroid aromatase that catalyses the conversion of C-19 androgens to estrogens. This study investigated whether polymorphisms of the CYP19 gene are associated with the risk of advanced endometriosis in Korean women. Blood samples were collected from 224 female patients with endometriosis of stages III and IV, as diagnosed by both pathologic and laparoscopic findings, and from a control group comprising of 188 women undergoing laparoscopic surgery or laparotomy for nonmalignant lesions. Single-nucleotide polymorphisms, restriction fragment length polymorphisms, and tetranucleotide tandem repeat polymorphisms were discriminated by the polymerase chain reaction (PCR). Haplotype analysis was also performed. CYP19 115T>C, 240G>A, and 1531C>T polymorphisms and [TTTA]n tetranucleotide repeat polymorphisms in the CYP19 gene and their haplotypes were not significantly associated with the risk of endometriosis. The risk of endometriosis also did not increase significantly with the number of higher risk alleles of the CYP19 gene. In conclusion, our findings suggest that CYP19 genetic polymorphisms are not associated with advanced-stage endometriosis in Korean women.

Single nucleotide polymorphisms and haplotypes of the genes encoding the CYP1B1 in Korean women: no association with advanced endometriosis

OBJECTIVE

To investigate whether single nucleotide polymorphisms and its haplotypes of gene encoding CYP1B1 are associated with the risk of advanced endometriosis in Korean women.

METHODS

We investigated 221 patients with histopathologically confirmed endometriosis rAFS stage III/IV and 188 control group women who were surgically proven to have no endometriosis. The genetic distribution of four different CYP1B1 polymorphisms at Ala119Ser, Leu432Val, Asp(449)(C>T), Asn453Ser were analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism of PCR products. Haplotype analysis was also performed.

RESULTS

We found no overall association between each individual CYP1B1 genotype or haplotype and the risk of endometriosis. Also, the odds ratio of each haplotypes of CYP1B1 showed no association with the risk of endometriosis.

CONCLUSIONS

These results suggest that CYP1B1 genetic polymorphism may not be associated with development of advanced endometriosis in Korean women.

Molecular mechanisms and biological plausibility underlying the malignant transformation of endometriosis: a critical analysis

Although population-based studies have unequivocally reported an increased risk of ovarian cancer in women with endometriosis, the biological evidence supporting the idea of endometriosis as a preneoplastic condition is scanty and not well substantiated. The fundamental features of human neoplasms (monoclonal growth, genetic changes, mutations in tumour suppressor genes and replicative advantage) have been evaluated in endometriotic lesions but results obtained are discordant. It is plausible that ectopic glands may expand monoclonally but the entity of this phenomenon is debated. According to some allelotyping studies, from one-third to one-half of endometriosis lesions would harbour somatic genetic changes in chromosomal regions supposed to contain genes involved in ovarian tumourigenesis, especially for the endometrioid histotype. These findings would be consistent with the progression model for carcinogenesis from the benign precursor to ovarian cancer but they could not be unequivocally replicated. Gene mutational studies are rare in this context. A single group has found missense mutations and deletions of PTEN gene in about 20% of ovarian endometriotic cysts. Moreover, in a model of genetically engineered mice harbouring an oncogenic allele of K-ras resulting in benign lesions reminiscent of endometriosis, a conditional deletion of PTEN caused the progression towards the endometrioid tumour. Based on these data, the causal link between endometriosis and ovarian endometrioid/clear cell carcinomas remains to be defined both in terms of entity of association and of underlying molecular mechanisms.

GSTM1, GSTT1 and CYP1A1 detoxification gene polymorphisms and their relationship with advanced stages of endometriosis in South Indian women

OBJECTIVE(S)

Studies on association between endometriosis and various phase I and phase II detoxification genes such as glutathione S-transferase M1 and theta 1 (GSTM1 and GSTT1) and cytochrome P450 (CYP1A1) have produced inconsistent results possibly because of ethnic differences. The present study was undertaken to investigate the frequency of the CYP1A1 (6235T>C) polymorphism and GSTM1, GSTT1 null mutations in a South Indian women's population with and without endometriosis.

METHODS

The frequencies of variants were studied in 310 women with laparoscopically proven endometriosis (rAFS III=101; IV=209) and 215 women without endometriosis using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

The GSTM1 null deletion showed significant association (P=0.028) with endometriosis. No significant difference was found in the frequencies of the GSTT1 null deletion in cases and controls. The frequencies of the variant CYP1A1 homozygous and heterozygous alleles in the cases were 9% and 44.2% against 14.4% and 42.3% in the controls. Further, we observed a considerable difference in the GSTM1 null deletion frequency in this population when compared with other populations of the world.

CONCLUSIONS

We observed an association between endometriosis and the GSTM1 null deletion, but not with GSTT1 null deletions or the CYP1A1 MspI polymorphism in South Indian women.

Glutathione-S-transferase P1 gene polymorphism and susceptibility to endometriosis

BACKGROUND

Glutathione-S-tranferase (GST) is the part of the key phase II detoxifying enzyme system. Many studies have investigated the role of GSTM1 and GSTT1 gene polymorphisms in endometriosis. Although GSTP1 was found to be one of the most abundant types of GST in genital system, there are insufficient data about the importance of the role of GSTP1 gene polymorphism in endometriosis.

METHODS

This case-control study involved 150 patients with endometriosis and 150 controls. The frequency of GSTP1 single nucleotide polymorphisms was evaluated using PCR and melting curve analysis.

RESULTS

The proportion of GSTP1 ile/ile tended to be higher in patients with endometriosis than control group, although the difference was not significant [odds ratio (OR)=1.53; 95% confidence interval (CI)=0.95-2.46]. In contrast, GSTP1 val/val was significantly higher in control patients and seems protective for endometriosis (OR=0.10; 95% CI=0.02-0.42).

CONCLUSION

The results of this study suggest that GSTP1 polymorphism might modulate the risk of endometriosis with significantly decreased risk for GSTP1 val/val and marginally increased risk for GSTP1 ile/ile. Further studies on not only the disease processes but also normal distribution of the enzyme in female genital tract may provide better understanding about the role of GST types and their polymorphs in endometriosis.