Association study of the TNF-α -1031T/C and VEGF +450G/C polymorphisms with susceptibility to endometriosis

Association between polymorphisms of cytokine genes and endometriosis: A comprehensive systematic review and meta-analysis

INTRODUCTION

There is abundant evidence to suggest that cytokines play a part in the mechanisms responsible for the formation of endometrium heterotopy. Cytokine synthesis is not only determined by the body's immunological reactivity but also by polymorphisms in the immune regulatory genes. The study of these polymorphisms in the immune regulatory genes offers up new possibilities in terms of prognosticating the risk of endometriosis and susceptibility to its treatment. The purpose of this comprehensive systematic review and meta-analysis was to investigate whether or not cytokine gene polymorphisms were linked to an increased chance of endometriosis.

METHODS

By searching MEDLINE, Scopus, and Web of Science databases, the relevant studies were identified. The odds ratio (OR) with 95% confidence interval (CI) was used to assess the association between TNF-α/IL-10/IL-6/TGF-β/IFN-γ/IL-1β gene polymorphisms and endometriosis risk.

RESULTS

A total of 5128 cases and 5334 controls in 32 eligible studies were included in the meta-analysis. Overall, results indicated the negative association between the cytokine gene polymorphisms and endometriosis in the dominant model of TNF-α (rs1799964): [OR] = 0.64, [CI]: 0.46-0.89) and a positive association in IFN-γ a13 allele: OR= 1.45, [CI]: 1.07-1.98; and IL-10 (rs1800872): [OR]= 1.60, [CI]: 1.21-2.12).

CONCLUSION

The present study suggests that IL-10 (rs1800872) and IFN-γ a13 allele may be a risk factors for endometriosis. Also, TNF-α (rs1799964) is associated with decreased susceptibility to 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 TNF-α gene T-1031C polymorphism with endometriosis: A meta-analysis

The single nucleotide polymorphism T-1031C has shown to have an important role in the regulation and transcription efficiency of TNF-α gene. Yet, the relationship between TNF-α T-1031C gene polymorphism and the development of endometriosis (EM) still remains unclear. The aim of this meta-analysis was to summarize the effects of TNF-α T-1031C gene polymorphism and clarify their possible association with EM. A comprehensive literature search was performed using PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials (up to August 10, 2019). A fixed- or random-effects model was employed according to the heterogeneity among studies. The log odds ratios and 95% confidence intervals (CIs) were estimated in the models of allele comparison (T vs C), homozygote comparison (TT vs CC) and (TC vs CC), dominant (TT vs TC + CC), hyperdominant (TT + CC vs TC), and recessive (TT + TC vs CC) to estimate the strength of the associations. A total of 7 case-control studies were included in this meta-analysis. Overall, significant associations between TNF-α T-1031C and EM were identified from (T vs C: log OR [95% CI] = 0.31 [-0.09, 0.71]; TT + CC vs TC: 0.27 [0.04, 0.50]; TC + CC vs TT: -0.83 [-1.19, -0.47]). On the other hand, no significant correlation was found in other gene models (TT vs TC: log OR [95% CI] = 0.89 [0.64, 1.13]; TT vs CC: 0.3 [-0.74, 1.36]; TT + TC vs CC: 0.17 [-0.81, 1.15]). In subgroup analyses by ethnicity or HWE P-value, there was a statistically significant association between TNF-α T-1031C polymorphisms and EM in the dominant model (TT vs TC + CC: log OR [95%] = -0.84 [-1.60, -0.09]) for the European population, and in hyperdominant model (TT + CC vs TC: log OR [95%] = 0.24 [0.001, 0.49]) for Asian population. To sum up, this meta-analysis showed that TNF-α T-1031C polymorphism was associated with EM susceptibility and has a protective effect in Asian and European populations.

The impact of vascular endothelial growth factor single nucleotide polymorphisms in the development and severity of endometriosis: A systematic review of the literature

OBJECTIVE

To review the impact of single nucleotide polymorphisms (SNPs) of the vascular endothelial growth factor (VEGF) gene in the development and severity of endometriosis.

SEARCH STRATEGY

We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases for published studies in the field.

SELECTION CRITERIA

We included prospective and retrospective observational studies.

DATA COLLECTION AND ANALYSIS

Data extraction was performed using a modified data form that was based in Cochrane`s data collection form for intervention reviews.

MAIN RESULTS

Twenty studies were included that investigated the frequency of the various alleles of the -460C/T, +405G/C, +936C/T, -2578A/C and -1154G/A SNPs. The Hardy-Weinberg equilibrium revealed that the different genotypes were comparable among patients with endometriosis and control women, as well as among patients with mild and severe forms of the disease. No differences were observed in the expression of the various alleles in the majority of cases. Ethnical variations were observed; however, the results should be regarded as inconclusive due to the small amount of available data.

CONCLUSIONS

The results of our meta-analysis suggest that the investigated single nucleotide polymorphisms are unlikely to significantly contribute to the development and severity of endometriosis.

Interleukin 1 alpha (IL1A) polymorphisms and risk of endometriosis in Iranian population: a case-control study

Endometriosis is one of the most common gynecological diseases and a major cause of pain and infertility. It is influenced by genetic, epigenetic, and environmental factors. Recently, genome-wide association studies have revealed a strong association between IL1A single nucleotide polymorphisms (SNPs) and increased risk of endometriosis in Japanese women. The aim of the present study was to evaluate the association of three IL1A SNPs, rs17561, rs1304037, and rs2856836 with the risk of endometriosis in Iranian population. Totally, 105 women with diagnosis of endometriosis and 102 healthy women as control group were included. Three SNPs of the IL1A, rs17561 G/T, rs1304037 A/G, and rs2856836 T/C, were genotyped by PCR and RFLP. The rs2856836 TC genotype was significantly higher (p = .002; OR = 3.1, 95% CI: 1.5-6.5) in the patients (28.1%) than the control group (12.7%). The rs2856836 CC genotype was significantly higher (p = .047; OR = 2.3, 95% CI: 1.0-5.3) in the patients (17.5%) than the control group (10.8%). The rs2856836 C allele was significantly higher (p = .001; OR = 2.2, 95% CI: 1.4-3.6) in the patients (31.6%) than the control group (17.2%). The IL1A rs2856836 T/C SNP was associated with susceptibility to endometriosis and the rs2856836 C allele may increase the risk of endometriosis in Iranian women.

Association between tumor necrosis factor-α gene-1031T/C promoter polymorphism and endometriosis in a European population

Background Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine which plays an important role in the pathogenesis of many diseases. Endometriosis is one of the most common gynecological diseases. The purpose of this study was to investigate the association of TNF-α-1031T/C polymorphism with the genetic susceptibility of endometriosis in a European population. Materials and methods In this case-control study, 51 endometriosis patients and 67 healthy control women participated. We used endometrial tissue from the patients and peripheral blood from the healthy women to extract DNA. Polymerase chain reaction (PCR) analysis and the restriction enzyme Bbs I were used to analyze the -1031 T/C polymorphism in the TNF-α gene promoter region. Statistical analysis was performed using Fisher's exact test. We also calculated the odds ratios. Results In the group of patients, 66.7% of women were detected with the TT genotype, 33.3% with the TC genotype and 0% with the CC genotype while in the control group, 46.3% had the TT genotype, 47.8% had the TC genotype and 6% had the CC genotype. There was a significant association between the TT genotype with endometriosis (p = 0.03). There was no significant deviation from the Hardy-Weinberg equilibrium. Conclusions The TC and CC genotypes appeared more often in the healthy women than the endometriosis patients and this shows that the C allele might have a protective role in endometriosis in the Greek population. Further studies are needed to specify the role of this polymorphism in pathogenesis of endometriosis and the mechanisms that protect the patients from the disease.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

The Association between TNF-alpha Gene Polymorphisms and Endometriosis in An Iranian Population

Background

Tumor necrosis factor-alpha (TNF-α) is an important cytokine in acute inflammatory response to infective factors. Based on investigation in different populations, it is thought that this response increases in patients with endometrio- sis due to the presence of cytokines such as TNF-α. This study aimed to examine the association of four TNF-α polymor- phisms, namely -238G/A, -308G/A, -857C/T and -863C/A, with susceptibility to endometriosis in an Iranian population.

Materials and Methods

We recruited 150 women with endometriosis and 150 women without endometriosis in this case-control study and collected 4 ml of blood from all subjects. After DNA extraction, the polymorphisms were geno- typed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results

The allele frequency of TNF-α -863C/A in the case and control groups showed a significant difference [odds ratios (OR)=0.64, 95% confidence interval (CI)=0.41-0.99, P=0.047] but the result is not significant when Adjust- ing for multiple testing (P=0.188). No significant difference in the allele frequencies of -238G/A (OR=1.07, 95% CI=0.51-2.25, P=0.862), -308G/A (OR=0.79, 95% CI=0.43-1.45, P=0.438) and -857C/T (OR=1.03, 95% CI=0.66- 1.61, P=0.887) was observed. We adjusted all four polymorphism genotypes by age and body mass index (BMI), however, no significant difference was detected. There was an association between the case and control and BMI when adjusting by age (OR=1.082, 95% CI=1.009-1.162, P=0.028).

Conclusion

For the first time the association of the four polymorphisms in the promoter region of the TNF-α gene with endometriosis has been conducted in women of Iranian origin. The present research reveals the -863 A allele may play a role in incidence of endometriosis among Iranian women. Development of endometriosis among those people with -863 A allele seems low. According to the results, the current study indicates that there might be a correlation between BMI and progression of endometriosis.

Polymorphisms in VEGF and KDR genes in the development of endometriosis: a systematic review

Abstract Objectives: to review studies that used case-control design to verify the association of polymorphisms in VEGF and KDR genes in the development of endometriosis. Methods: the systematic review selected articles published until September 1, 2015 from PubMed, MEDLINE, BVS, SciELO databases, considering the following key words: endometriosis and ("polymorphism" or "SNP" or "genetic polymorphism") and ("VEGF" OR "Vascular endothelial growth factor" or "VEGFR-2" or "Vascular endothelial growth factor-2" or "KDR" or "Kinase Insert Domain Receptor"). Results: 106 articles were identified, only 11 were eligible. Discrepant results were observed regarding polymorphisms in VEGF gene in the development of endometriosis, which can be explained by methodological differences, sample size, eligible control type, using the unadjusted risk estimates and the heterogeneity of the studied population. Only one study investigated polymorphisms in KDR gene in the development of endometriosis, however it was ineligible for this review. Conclusions: to avoid discrepancy in the results, we suggest that the ideal control group should be formed by fertile women and free of gynecological diseases. Multicentric studies with adequate design, involving different population besides the combined analysis on polymorphisms in VEGF and KDR genes are still necessary to contribute in the understanding of this disease, which are social, clinical and economical problems.

Contrast-Enhanced Sonographic Features Before and After Interventional Treatment of Ovarian Endometrial Cysts

OBJECTIVES

The purpose of this study was to assess contrast-enhanced sonography features before and after interventional treatment of ovarian endometrial cysts.

METHODS

We retrospectively analyzed 53 patients with ovarian endometrial cysts who underwent contrast-enhanced sonography before and after interventional treatment to assess the sonographic features of the cysts at these different times. The sonographic features and quantitative parameters for the cysts were compared before and after treatment.

RESULTS

The wash-in mode showed rapid annular enhancement of the cyst wall and slow wash-out with even and uneven enhancement types. Compared to the internal iliac artery, the enhancement intensity was weaker, and the wash-in and wash-out times were longer in the cyst wall; furthermore, all 5 quantitative parameters differed between the cyst wall and internal iliac artery. The wash-in and wash-out characteristics of the cysts before and after interventional treatment were almost identical. The enhancement was primarily even before treatment and uneven after treatment; the enhancement intensity was low in all cases. Although the wash-in time before and after treatment did not differ, the wash-out time for the cysts before treatment was significantly lower than that observed after treatment. Two quantitative parameters differed before and after treatment.

CONCLUSIONS

The contrast-enhanced sonographic features and quantitative parameters for the walls of ovarian endometrial cysts differed before and after ultrasound-guided interventional treatment. These characteristics could be valuable for evaluating the efficacy of interventional treatment of ovarian endometrial cysts.

Evaluation of Tumor Necrosis Factor Alpha Polymorphism Frequencies in Endometriosis

BACKGROUND

The pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-α), is a pathogenic element for a number of disorders. Previous studies have reported that the -1031 T/C and -238 G/A polymorphisms in the promoter region of the TNF-α gene are important factors in reproductive-related disorders. One of the most common gynecological diseases of women during the reproductive years is endometriosis. This study aims to assess an association between the -1031 T/C, -238 G/A and -308 G/A polymorphisms of the TNF-α gene promoter region to endometriosis.

MATERIALS AND METHODS

In this case-control study, we enrolled 65 endometriosis patients and 65 matched healthy control women by simple sampling. Polymerase chain reaction (PCR) analysis was used to analyze -1031 T/C, -238 G/A and -308 G/A polymorphisms in the TNF-α gene promoter region. Statistical analysis was performed using the chi-square test. P values less than 0.05 were considered statistically significant.

RESULTS

We found a strong association between the -1031 T/C polymorphism in the promoter region of the TNF-α gene with endometriosis (P=0.001). There were no significant associations between the -238 G/A (P=0.243) and -308 G/A (P=1) polymorphisms with endometriosis and again endometriosis stages have no association with these polymorphisms.

CONCLUSION

The -1031 T/C polymorphism and CC genotype can be used as a relevant marker to identify women at risk of developing endometriosis.

Genetics of endometriosis

Endometriosis is a heritable complex disorder that is influenced by multiple genetic and environmental factors. Identification of these genetic factors will aid a better understanding of the underlying biology of the disease. In this article, we describe different methods of studying genetic variation of endometriosis, summarize results from genetic studies performed to date and provide recommendations for future studies to uncover additional factors contributing to the heritable component of endometriosis.

The association between vascular endothelial growth factor (VEGF) +405G>C genetic polymorphism and endometriosis

The vascular endothelial growth factor (VEGF) is one of the most important candidate genes for the development of endometriosis, and VEGF genetic polymorphisms might be potentially associated with endometriosis risk. However, the results still remain controversial. The objective of this study aimed to perform a comprehensive meta-analysis to explore a better understanding of the effects of VEGF +405G>C genetic polymorphism on the risk of endometriosis. A total of eleven eligible studies were eventually identified in this meta-analysis, including 2829 endometriosis cases and 2947 controls. In the overall analysis, no significant association between the VEGF +405G>C genetic polymorphism and the risk of endometriosis was detected in all genetic models (for homozygote comparison [CC versus vs. GG]: OR = 1.21, 95% CI 0.67-2.19, P = 0.537; for heterozygote comparison [CG vs. GG]: OR = 1.16, 95% CI 0.86-1.56, P = 0.348; for dominant comparison CC/CG vs. GG: OR = 1.10, 95% CI 0.93-1.30, P = 0.263; for recessive comparison [CC vs. CG/GG]: OR = 1.03, 95% CI 0.73-1.47, P = 0.857; allele comparison [C vs. G]: OR = 0.99, 95% CI 0.70-1.40, P = 0.962). In the subgroup analysis by ethnicities, there was no significant association between VEGF +405G>C genetic polymorphism and endometriosis risk in Asians and/or Caucasians under all genetic models (all P-values >0.05). No publication bias was observed in this study. This meta-analysis supports that the VEGF +405G>C genetic polymorphism is not significant associated with the risk of endometriosis.

Association of common variations of the E-cadherin with endometriosis

Endometriosis is a polygenic and multifactorial disease. E-cadherin (CDH1) gene encodes an epithelial cell-cell adhesion glycoprotein that modulates a wide variety of processes, including cell polarization, migration and cancer metastasis. Decreased expression of CDH1 in epithelial cells in peritoneal endometriosis has been reported in advanced stages of endometriotic lesions. We investigated the CDH1 -160C/A and +54C/T variations with susceptibility to endometriosis in an Iranian population. In this case-control study, 149 patients with endometriosis (stages I-IV) and 151 healthy women as controls were included. Genotyping was performed using PCR-RFLP method. A p value of <0.05 was considered statistically significant. The CDH1 + 54TT genotype was significantly lower (p = 0.012; OR = 0.30, 95% CI: 0.12-0.77) in the patients (11.6%) than the control group (26.7%). The CDH1 + 54T allele was significantly lower (p = 0.001; OR = 0.55, 95% CI: 0.38-0.77) in the cases (35.7%) compared with the control group (50.3%). No association was found between CDH1 - 160C/A polymorphism and endometriosis. The CDH1 +54C/T was associated with susceptibility to endometriosis in Iranian population, and +54T allele may have a protective role in progression of endometriosis.

Role of vascular endothelial growth factor polymorphisms (-2578C>A, -460 T>C, -1154G>A, +405G>C and +936C>T) in endometriosis: a case-control study with Brazilians

Background

Endometriosis is regarded as a complex and heterogeneous disease in which genetic and environmental factors contribute to the phenotype. The Vascular Endothelial Growth Factor (VEGF) plays important roles in the pathogenesis of endometriosis. The present study was aimed at investigating the contribution of VEGF polymorphisms as risk factors for the development of endometriosis. This is the first study to evaluate the combined influence of the five most common VEGF polymorphisms.

Methods

This study was conducted at two hospitals from the Brazilian public health system, and comprised 294 women submitted to laparoscopic or laparotomy surgery: 182 patients had a histologically confirmed diagnosis of endometriosis (cases), whereas 112 had no evidence of the disease (controls). The VEGF polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model.

Results

Endometriosis patients and controls did not differ regarding age distribution, whereas the body mass index was significantly lower in endometriosis patients, when compared with controls (23.1 ± 3.9 versus 27.3 ± 5.9, P < 0.001). The evaluation of gynecological symptoms, including dysmenorrhea, non-cyclic chronic pelvic pain, dyspareunia and infertility, indicates significantly higher prevalences among endometriosis cases. The variant allele -1154A was significantly associated with endometriosis, either considering all cases (OR: 1.90, 95% CI: 1.23–2.97), deep infiltrating endometriosis (DIE) (OR: 1.83, 95% CI: 1.16-2.90) or moderate and severe endometriosis (stages III-IV) (OR: 1.97, 95% CI: 1.21-3.19). No significant differences were found in allele or genotype distributions of the –2578C > A, -460 T > C, +405G > C and +936C > T polymorphisms between endometriosis cases and controls. A total of six haplotypes were inferred derived from four polymorphisms (-2578C > A, -460 T > C, -1154G > A and +405G > C). There was a protective association between CCGG haplotype and endometriosis, either considering all cases (OR: 0.36, 95% CI: 0.15–0.86), DIE (OR: 0.37 95% CI: 0.15 – 0.90) or stages III-IV (OR: 0.35 95% CI: 0.13 – 0.95).

Conclusions

The present results indicate a positive association between VEGF -1154G > A and the risk of developing endometriosis, whereas the CCGG haplotype may be protective against the development of disease.