Evaluation of clinical parameters and estrogen receptor alpha gene polymorphisms for patients with endometriosis

Sex hormone-related polymorphisms in endometriosis and migraine: A narrative review

Some evidence indicates endometriosis and migraine have a common genetic predisposition in sex-hormone genes, which could have important implications for the treatment of these two heterogenous conditions. To date, the genes responsibility remains unknown. Based on the biological hypothesis that polymorphisms of genes involved in sex-hormone pathways may influence estrogen levels and phenotypes of both disorders, we did a literature search for candidate sex-hormone genes and genes involved in the metabolism of estradiol. The aim was to review the evidence for shared sex-hormone-related polymorphisms between endometriosis and migraine and provide an exhaustive overview of the current literature. We included case-control studies investigating associations between candidate sex-hormone-related genes and the disorders endometriosis and migraine, respectively. Results showed three overlapping sex-hormone-associated polymorphisms in estrogen receptor genes that are associated with both conditions. To confirm possible associations with other sex-hormone genes, larger studies are needed.

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 of estrogen and progesterone receptors and endometriosis: Meta-analysis

Purpose:

To investigate the association between polymorphisms in the genes of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor and the genesis of endometriosis.

Methods:

Systematic review and meta-analysis of articles published fully in the PubMed database, in Portuguese, English, or Spanish, from 2006 to 2017, using the descriptors: “endometriosis,” “polymorphism,” “ESR1,” “ESR2,” “PROGINS,” “rs9340799,” “rs4986938,” and “rs1042838.”

Results:

A total of 20 studies were included based on the criterion of search for susceptibility to endometriosis related to polymorphisms of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor genes. Analysis of all polymorphisms found no association with endometriosis.

Conclusion:

This meta-analysis showed that estrogen receptor alpha, estrogen receptor beta, and progesterone receptor polymorphisms are not related to susceptibility to endometriosis. However, such results may be able to provide more detailed interpretations of how they influence the pathogenesis of endometriosis.

Inhibition of adhesion, proliferation, and invasion of primary endometriosis and endometrial stromal and ovarian carcinoma cells by a nonhyaluronan adhesion barrier gel

Endometriosis is a chronic disease of women in the reproductive age, defined as endometrial cells growing outside of the uterine cavity and associated with relapses. Relapses are hypothesized to correlate with incomplete surgical excision or result from nonrandom implantation of new endometrial implants in adjacent peritoneum. Thus, surgical excision could lead to free endometriotic cells or tissue residues, which readhere, grow, and invade into recurrent lesions. Barrier agents are frequently used to prevent postoperative adhesions. We tested if the absorbable cell adhesion barrier gel Intercoat consisting of polyethylene oxide and sodium carboxymethyl cellulose could inhibit cellular adhesion, proliferation, and invasion of primary endometriosis and endometrial cells. Due to an association of endometriosis with ovarian carcinoma, we tested two ovarian carcinoma cell lines. Prior to cell seeding, a drop of the barrier gel was placed in cell culture wells in order to test inhibition of adherence and proliferation or coated over a polymerized collagen gel to assay for prevention of invasion. Results showed that the barrier gel significantly inhibited cell adherence, proliferation, and invasion of endometriosis and endometrial stromal cells as well as ovarian carcinoma cells in culture. Our findings could help to prevent local cell growth/invasion and possible consequent recurrences.

ESR1 rs9340799 is associated with endometriosis-related infertility and in vitro fertilization failure

Estrogen receptor alpha has a central role in human fertility by regulating estrogen action in all human reproductive tissues. Leukemia inhibitory factor (LIF) expression, a cytokine critical for blastocyst implantation, is mediated by estrogen signaling, so we hypothesized that ESR1 gene polymorphisms might be candidate risk markers for endometriosis-related infertility and in vitro fertilization (IVF) failure. We included 98 infertile women with endometriosis, 115 infertile women with at least one IVF failure and also 134 fertile women as controls. TaqMan SNP assays were used for genotyping LIF (rs929271), MDM2 (rs2279744), MDM4 (rs1563828), USP7 (rs1529916), and ESR1 (rs9340799 and rs2234693) polymorphisms. The SNP ESR1 rs9340799 was associated with endometriosis-related infertility (P < 0.001) and also with IVF failure (P = 0.018). After controlling for age, infertile women with ESR1 rs9340799 GG genotype presented 4-fold increased risk of endometriosis (OR 4.67, 95% CI 1.84–11.83, P = 0.001) and 3-fold increased risk of IVF failure (OR 3.33, 95% CI 1.38–8.03, P = 0.007). Our results demonstrate an association between ESR1 rs9340799 polymorphism and infertile women with endometriosis and also with women who were submitted to IVF procedures and had no blastocyst implantation.

The 17Beta-Hydroxysteroid Dehydrogenase Type 1 Gene Polymorphism and Endometriosis

Purpose

Endometriosis is a chronic, painful disease that affects the female genital tract with unknown definite etiology, though there are multiple theories that try to explain its etiology. Genetic causes are suggested in the most widely accepted theories, and this study examined the association between the HSD17B1 gene polymorphism and endometriosis and its severity.

Methods

Twenty-five patients with clinical suspicion of endometriosis confirmed by laparoscopic examination were admitted to the Gynecology and Obstetrics Department in the Minia University Hospital, and 25 women were enrolled as controls. All subjects underwent genetic analysis for the HSD17B1 gene polymorphism.

Results

There were significant associations between genotyping analysis of the cases and controls: G/G, A/G and A/A distributions among the cases were 8%, 60% and 32%, respectively, while in controls, they were 60%, 32% and 8%, respectively (p = 0.002, p = 0.05 and p = 0.03, respectively). There were no associations between the HSD17B1 gene polymorphism and severity of endometriosis.

Conclusion

Genetic analysis of the HSD17B1 gene polymorphism showed it to have an important role in the etiology of endometriosis. Extensive further studies are recommended for further genes that may be associated with endometriosis.

Estrogen receptor-alpha gene PvuII (T/C) and XbaI (A/G) polymorphisms and endometriosis risk: a meta-analysis

Estrogen receptor-alpha (ER-α) polymorphisms have been hypothesized to be associated with the risk of endometriosis (EMT) development by many epidemiological studies, however, the available results were conflicting. To derive a more precise estimation of association between the ER-α PvuII (T/C) and XbaI (A/G) polymorphisms and risk of EMT, we performed a meta-analysis. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) for ER-α polymorphisms and EMT were calculated in a fixed-effects model and a random-effects model when appropriate. This meta-analysis included 20 case-control studies with 1752 cases and 1742 controls for PvuII polymorphism and 15 case-control studies with 1349 cases and 1411 controls for XbaI polymorphism. For PvuII T/C polymorphism, no obvious associations were found for all genetic models when all studies were pooled into the meta-analysis. In the subgroup analyses by ethnicity, country, HWE in controls and study sample size, a significantly increased risk was observed among Caucasians (recessive model, OR=2.56, 95% CI=1.06-6.16) and among studies without the HWE (recessive model, OR=1.85, 95% CI=1.20-2.84). For XbaI A/G polymorphism, also no obvious associations were found for all genetic models. In the subgroup analyses by ethnicity, country, HWE in controls and study sample size, still no obvious associations were found. No publication bias was found in the present study. This meta-analysis suggests that ER-α gene PvuII (T/C) and XbaI (A/G) polymorphisms may not be associated with EMT risk, while the observed increase in risk of EMT may be due to small-study bias.

Endometriosis: a premenopausal disease? Age pattern in 42,079 patients with endometriosis

PURPOSE

The objectives of this study were to examine the age distribution among women suffering from endometriosis and to establish that endometriosis is not a disease that occurs only in premenopausal women. The null hypothesis was that there are also postmenopausal women with endometriosis.

METHODS

In a retrospective epidemiological study, a descriptive analysis of data from the Federal Statistical Office in Germany for 2005 and 2006 was carried out. A total of 42,079 women in Germany were admitted for surgical treatment due to histologically confirmed endometriosis during this period. The patients' age distribution was examined and they were assigned to 5-year age groups and then to premenopausal, perimenopausal, and postmenopausal subgroups.

RESULTS

A total of 20,835 women in 2005 and 21,244 in 2006 were admitted to hospital for the treatment of endometriosis. In the premenopausal group (age 0-45 years), there were 33,814 patients (80.36 %); 23 patients (0.05 %) in this premenopausal group were younger than 15. There were 7,191 patients (17.09 %) in the perimenopausal group (45-55 years), and the postmenopausal group (55-95 years) included 1,074 patients (2.55 %).

CONCLUSIONS

The assumption that endometriosis is a disease of the premenopausal period and in women of reproductive age needs to be called into question, as well as the influence of estrogen in fully developed endometriosis. Due to the relatively high prevalence of the condition in patients aged over 40, physicians should consider endometriosis in cases of unclear pelvic pain in this age group.

Pathogenesis of endometriosis: the role of genetics, inflammation and oxidative stress

INTRODUCTION

Endometriosis is defined as the presence of endometrial tissue outside the uterine cavity.

MATERIALS AND METHODS

The etiology of this multifactorial disease is still unresolved and an increasing number of studies suggest that genetic, hormonal, environmental, immunological and oxidative factors may all play an important role in the pathogenesis of this disorder.

CONCLUSIONS

In this literature review, inflammatory activity, oxidative stress as well as genetic abnormalities and mutations have been studied in an effort to identify factors predisposing to endometriosis.

Genetic variation in the sex hormone metabolic pathway and endometriosis risk: an evaluation of candidate genes

OBJECTIVE

To evaluate the relationship between common genetic variation in genes involved in the biosynthesis and signaling of estrogen and progesterone and endometriosis risk.

DESIGN

Genetic polymorphism analysis.

SETTING

Population-based case-control study conducted in Group Health Cooperative enrollees in western Washington.

PATIENT(S)

Women with newly diagnosed, surgically confirmed endometriosis between 1996 and 2001 (n = 256) and age- and reference year-matched female control subjects without a history of endometriosis (n = 567).

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

We evaluated the relationship between common genetic variation and endometriosis risk, using gene-based tests and single-variant analysis of genetic polymorphisms in ESR1, ESR2, PGR, CYP17A1, CYP19A1, HSD17B1, HSD17B2, CYP1A1, CYP1A2, COMT, and GSTM1.

RESULT(S)

The most consistent gene-based association with endometriosis risk was for CYP19A1. We did not find evidence for consistent significant associations between previously reported candidate SNPs in sex hormone-related genes and endometriosis risk.

CONCLUSION(S)

In summary, we report increased endometriosis risk with CYP19A1 gene-based tests; replication of the association between endometriosis and this gene or gene region is necessary in a larger study population.

RsaI polymorphism of the ERβ gene in women with endometriosis

We examined the frequency of RsaI polymorphism of the ERβ gene in 54 patients diagnosed with endometriosis and 46 controls. Peripheral blood was collected from women undergoing laparoscopy with a confirmed diagnosis of endometriosis. Polymorphisms of the ERβ gene and p53 were assessed by PCR and analyzed on 2% agarose gel stained with ethidium bromide. The AG polymorphism genotype frequency in patients with endometriosis was 59.3%, with 40.7% GG. In the control group, the frequency of AG was 6.5%, with 93.5% GG. The frequency of heterozygous AG was nine times higher in patients with endometriosis than in the control group (P < 0.0001).

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.

Advances in the genetics of endometriosis

Endometriosis is a gynecological disease characterized by implantation of endometrial tissue outside of the uterus. Early familial aggregation and twin studies noted a higher risk of endometriosis among relatives. Studies on the roles of the environment, genetics and aberrant regulation in the endometrium and endometriotic lesions of women with endometriosis suggest that endometriosis arises from the interplay between genetic variants and environmental factors. Elucidating the hereditary component has proven difficult because multiple genes seem to produce a susceptibility to developing endometriosis. Molecular techniques, including linkage and genome-wide analysis, have identified candidate genes located near known loci related to development and regulation of the female reproductive tract. As new candidate genes are discovered and hereditary pathways identified using technologies such as genome-wide analysis, the possibility of prevention and treatment becomes more tangible for millions of women affected by endometriosis. Here, we discuss the advances of genetic research in endometriosis and describe technologies that have contributed to the current understanding of the genetic variability in endometriosis, variability that includes regulatory polymorphisms in key genes.

Expression of estrogen and progesterone receptors in subcutaneous endometriosis

Endometriosis is a clinical disorder defined by the presence of functional endometrial tissue outside the uterine cavity. Depending on the localization of the endometrial tissue related to the pelvis, the endometriosis can be classified either as intrinsic or extrinsic. The prevalence of endometriosis is difficult to determine. Statistical data show that endometriosis could be associated both with female infertility (20%) and pelvic pains (24%), while in 4.1% of affected women, endometriosis has asymptomatic forms. The total prevalence of endometriosis is estimated to be between 5-10%. A 35-year-old woman from Knic, Serbia, was admitted to the Obstetrics and Gynecology Clinic of the Clinical Center in Kragujevac for surgical treatment of a suspicious swelling in the pubic region. Following surgical intervention, a nut-sized tumor was removed and sent for both pathohistological and immunohistochemical analysis. The results confirmed the presence of subcutaneous endometriosis positive for both estrogen and progesterone receptors. Endometriosis is usually described as a steroid hormone-dependent change that resembles the eutopic endometrial tissue characteristic for the presence of both glandular and stromal tissues. Given the fact that endometrial lesions are estrogen-dependent tumors, a crucial factor in the development of endometriosis is a late exposure to the hormone, mostly estrogen. Spontaneous subcutaneous endometriosis is rarely observed, but it could be assumed if there is recurrent pelvic pain which intensifies during menstruation. Given the fact that endometriosis coexists with different autoimmune diseases, multidisciplinary approaches are required for its proper diagnosis. .

Frequency of endometriotic lesions in peritoneum samples from asymptomatic fertile women and correlation with CA125 values

CONTEXT AND OBJECTIVE

Serological testing for CA125 has been widely used to detect endometriosis and to monitor its progression. However, controversy still exists regarding the usefulness of the plasma CA125 assay for diagnosing endometriosis. Furthermore, some authors have described superficial endometriosis as a cyclical and normal phenomenon in women's lives, and have indicated that development and progression of this disease would only occur in some women as a result of immunological changes. This study aimed to determine the frequency of endometriosis and the correlation between serum CA125 levels and the presence of endometriotic lesions in the peritoneum of asymptomatic fertile patients.

DESIGN AND SETTING

Cross-sectional study at the Family Planning outpatient clinic of Faculdade de Medicina do ABC.

METHODS

Eighty asymptomatic fertile patients who underwent tubal sterilization surgery were studied. Blood and peritoneum samples were collected. CA125 levels were measured from blood samples, and peritoneum biopsies were studied using histopathological tests.

RESULTS

Histopathological evaluation of the peritoneum revealed that 16.25% of the patients had minimal or mild endometriosis. There was no statistically significant difference in CA125 levels between patients with and without endometriosis.

CONCLUSION

The presence of endometriotic lesions in the peritoneum of fertile patients supports the hypothesis that incidental findings of minimal or mild endometriosis may not be of clinical significance, and that the progression of the disease probably occurs as a result of immunological and genetic abnormalities. Serum CA125 levels did not show any diagnostic significance with regard to detecting the disease.

Polymorphisms in estrogen metabolism and estrogen pathway genes and the risk of miscarriage

PURPOSE

This study investigated genetic variations in the estrogen pathway and their association with miscarriages.

METHODS

A total of 483 patients were recruited from a comprehensive control group for case-control studies. Three variants of the CYP19A1 gene (rs10046, rs4646 and rs700519) and one variant each of the estrogen (ESR1) and progesterone (PGR) receptor genes (rs3020314 and rs1042838) were investigated using polymorphism genotyping. The chi-squared test and one-way analysis of variation (ANOVA) were used for statistical analysis.

RESULTS

For rs10046 (CYP19A1), the C/C genotype was associated with a greater frequency of miscarriages (P = 0.017). The other genotypes were not found to be associated with recurrent miscarriage.

CONCLUSIONS

This is the first study that has identified a single-nucleotide polymorphism in the aromatase gene that suggests a significant association between genotypes and miscarriage. As aromatase is an essential enzyme in the estrogen pathway, it may be speculated that variations in the aromatase gene in some way give rise to different conditions in the endocrine environment that can lead to impaired fertility.

Single nucleotide polymorphisms in the progesterone receptor gene and association with uterine leiomyoma tumor characteristics and disease risk

OBJECTIVE

Uterine benign leiomyomas result from proliferation of a single smooth-muscle cell and their growth is affected by steroid hormones via steroid hormone receptors. This investigation analyzed the +331G/A and the V600L single nucleotide polymorphisms in the progesterone receptor, and correlated their incidence with clinical and tumor parameters as well as disease risk.

STUDY DESIGN

Peripheral blood DNA was analyzed for the frequency of both progesterone receptor single nucleotide polymorphisms in 270 women with uterine leiomyomas compared with 163 control women without uterine leiomyomas.

RESULTS

No correlation was found for both single nucleotide polymorphisms or the risk for developing myoma; however, statistical significant associations were found for single nucleotide polymorphism genotypes with specific clinical and tumor characteristics, eg, endometriosis, number of live births, menstrual cycle disorder, and leiomyoma focality.

CONCLUSION

Our findings support that specific genotypes in the progesterone receptor may be involved in tumor growth and metastasis but not in tumor initiation.

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.

Association of estrogen receptor alpha and interleukin-10 gene polymorphisms with endometriosis in a Chinese population

OBJECTIVE

To determine whether polymorphisms of the estrogen receptor alpha (ERalpha) and interleukin-10 (IL-10) genes are associated with endometriosis in a Chinese population.

DESIGN

Association study.

SETTING

University hospital.

PATIENT(S)

Chinese women diagnosed with endometriosis by laparotomy or laparoscopy.

INTERVENTION(S)

Determination of polymorphisms of the ERalpha and IL-10 genes was performed by polymerase chain reaction and restriction fragment length polymorphism analysis in 214 affected women and 160 controls.

MAIN OUTCOME MEASURE(S)

Frequency and distribution of PvuII and XbaI polymorphisms of ERalpha and of BslI, SspI, and RsaI polymorphisms of IL-10.

RESULT(S)

There was no significant difference between the endometriosis patients and the control groups in the genotype frequency of ERalpha-PvuII and promoter of IL-10 gene polymorphisms in the position of -1082. However, the frequency of ERalpha-XbaI and -592 or -819C alleles of IL-10 in the endometriosis group was significantly higher than that of controls, and further analysis showed that the X allele of ERalpha-XbaI was associated with endometriosis.

CONCLUSION(S)

The X allele of ERalpha-XbaI and the -592 or -819 C allele of IL-10 are associated with endometriosis.

XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes but not XRCC4 intron 3 gene polymorphism are associated with higher susceptibility for endometriosis

DNA repair systems act to maintain genome integrity in the face of replication errors, environmental insults, and the cumulative effects of age. Genetic variants in DNA repair genes such as X-ray repair cross-complementing group 4 (XRCC4) might influence the ability to repair damaged DNA. Herein we aimed to investigate whether some XRCC4-related polymorphisms were associated with endometriosis susceptibility. Women were divided: (1) severe endometriosis (rAFS stage IV, n = 136) and (2) nonendometriosis groups (n = 112). The polymorphisms of XRCC4 codon 247, XRCC4 promoter -1394, and XRCC4 intron 3 insertion/deletion (I/D) polymorphism were amplified by PCR and detected by electrophoresis after restriction enzyme (BBS I, Hinc II) digestions. Genotypes and allelic frequencies in both groups were compared. We observed that XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes, but not XRCC4 intron 3 I/D polymorphism, are associated with higher susceptibility for endometriosis. Distributions of XRCC4 codon 247*C homozygote/heterozygote/A homozygote, and C/A allele in both groups were: (1) 89/9.5/1.5% and 93.7/6.3%; (2) 97.3/2.7/0%, and 98.7/1.3% (P < 0.05). Proportions of XRCC4 promoter -1394*T homozygote/heterozygote/G homozygote and T/G allele in both groups were: (1) 94.1/5.2/0.7% and 96.7/3.3%, and (2) 79.4/17.9/2.7% and 88.4/11.6% (P < 0.005). Proportions of XRCC4*I homozygote/heterozygote/D homozygote and A/C allele in both groups were: (1) 67.6/30.9/1.5% and 83.2/16.8%, and (2) 70.5/24.1/5.4% and 82.6/17.4% (nondifference). We conclude that XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes and alleles, but not XRCC4 intron 3 I/D polymorphism, might be associated with endometriosis susceptibilities and pathogenesis.

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.