New considerations for the pathogenesis of endometriosis

Immune pathway through endometriosis to ovarian cancer

Endometriosis is an estrogen-dependent inflammatory disease, defined by the presence of functional endometrial tissue outside of the uterine cavity. This disease is one of the main gynecological diseases, affecting around 10%-15% women and girls of reproductive age, being a common gynecologic disorder. Although endometriosis is a benign disease, it shares several characteristics with invasive cancer. Studies support that it has been linked with an increased chance of developing endometrial ovarian cancer, representing an earlier stage of neoplastic processes. This is particularly true for women with clear cell carcinoma, low-grade serous carcinoma and endometrioid. However, the carcinogenic pathways between both pathologies remain poorly understood. Current studies suggest a connection between endometriosis and endometriosis-associated ovarian cancers (EAOCs) via pathways associated with oxidative stress, inflammation, and hyperestrogenism. This article aims to review current data on the molecular events linked to the development of EAOCs from endometriosis, specifically focusing on the complex relationship between the immune response to endometriosis and cancer, including the molecular mechanisms and their ramifications. Examining recent developments in immunotherapy and their potential to boost the effectiveness of future treatments.

Vorinostat decrease M2 macrophage polarization through ARID1A6488delG/HDAC6/IL-10 signaling pathway in endometriosis-associated ovarian carcinoma

Endometriosis is a common disease in women and may be one of the factors that induces malignant epithelial ovarian tumors. Previous studies suggested that endometriosis is related to ARID1A mutation mediating the expression of HDAC6, but the detailed pathogenic mechanism is still unclear. First, we collected endometriosis-associated ovarian carcinoma (EAOC) clinical samples and examined the expression of HDAC6. Our results found that the high HDAC6 expression group was positively correlated with EAOC histology (P = 0.015), stage (P < 0.000), and tumor size (P < 0.000) and inversely correlated with survival (P < 0.000). We also found that ARID1A^6488delG/HDAC6 induced M2 polarization of macrophages through IL-10. In addition, the HDAC inhibitor (HDACi) vorinostat inhibited cell growth and blocked the effect of HDAC6. Tomographic microscopy was used to monitor the live cell morphology of these treated cells, and we found that vorinostat treatment resulted in substantial cell apoptosis by 3 h 42 min. Next, we established a transgenic mouse model of EAOC and found that vorinostat significantly reduced the size of ovarian tumors by inhibiting M2 macrophage polarization in mice. Together, these data demonstrate that the signaling pathway of E4F1/ARID1A^6488delG/HDAC6/GATA3 mediates macrophage polarization and provides a novel immune cell-associated therapeutic strategy targeting IL-10 in EAOC.

The Phytochemical Profile and Biological Activity of Malva neglecta Wallr. in Surgically Induced Endometriosis Model in Rats

Leaves and aerial parts of Malva neglecta Wallr. have been traditionally used in Anatolia for the treatment of pain, inflammation, hemorrhoids, renal stones, constipation, and infertility. This study investigated the effects of M. neglecta leaves in a rat endometriosis model. The dried plant material was extracted with n-hexane, ethyl acetate, and methanol, successively. Experimental endometriosis was surgically induced in six-week-old female, non-pregnant, Wistar albino rats by autotransplant of endometrial tissue to the abdominal wall. After twenty-eight days, rats were evaluated for a second laparotomy. Endometrial foci areas were assessed, and intraabdominal adhesions were scored. Rats were divided into five groups as control, n-hexane, ethyl acetate, methanol, and aqueous extracts, as well as reference. At the end of the treatment, all rats were sacrificed and endometriotic foci areas and intraabdominal adhesions were re-evaluated and compared with the previous findings. Moreover, peritoneal fluid was collected to detect tumor necrosis factor- α (TNF-α), vascular endothelial growth factor (VEGF), and interleukin-6 (IL-6) levels, and cDNA synthesis, and a quantitative real-time polymerase chain reaction (PCR) test was done. The phytochemical content of the most active extract was determined using High-Performance Liquid Chromatography (HPLC). Both endometrial volume and adhesion score decreased significantly in the group treated with methanol extract. In addition, significant decreases were observed in TNF-α, VEGF, and IL-6 levels in animals administered methanol extract. HPLC results showed that the activity caused by the methanol extract of M. neglecta was due to the polyphenols. Taken together, these novel findings indicate that M. neglecta may be a promising alternative for the treatment of endometriosis.

Association of leptin and adiponectin levels with endometriosis: a systematic review and meta-analysis

BACKGROUND

We aimed to summarize the available data regarding the levels of leptin and adiponectin and the key modulators of endometriosis compared to the controls.

METHODS

The electronic databases such as MEDLINE, Embase, Scopus, Cochrane Library, and Web of Science were searched up to October 2020. The circulating and peritoneal levels of leptin and circulating levels of adiponectin were included. We used the Cochrane's Q test and the I² statistic in this study. These tests' weighted mean difference (WMD) and 95% CIs were considered as the summary effect size. They were then pooled using a random-effects model with the DerSimonian-Laird method.

RESULTS

Twenty eligible articles (or 25 studies) with 2645 participants (1362 women with endometriosis and 1283 controls) were included. Pooled results showed that women with endometriosis had significantly higher leptin levels (WMD = 4.45 mg/ml, 95%CI = 2.42-6.49, p < .01) and leptin/BMI ratio (WMD = 0.32 mg/ml, 95%CI = 0.23-0.42, p < .001) than the controls, whereas adiponectin levels (WMD = -0.24 mg/ml, 95%CI = -4.27 to -0.01, p = .038) were significantly lower. The pooled results also indicated significantly lower leptin levels in women with advanced-stage endometriosis (WMD = -8.07 mg/ml, 95%CI = -14.22 to -1.92, p = .01) than in the early stage. It was found, however, that there were no significant differences in adiponectin levels of women with advanced-stage endometriosis (WMD = -0.16 mg/ml, 95%CI = -0.64 to 0.32, p = .512) and the early-stage ones.

CONCLUSION

We showed that leptin levels and leptin/BMI ratio were significantly higher in women with endometriosis than the controls. Nonetheless, patients with endometriosis had significantly lower levels of adiponectin than the controls.

Current Knowledge on Endometriosis Etiology: A Systematic Review of Literature

Objective

To review the mechanisms of endometriosis development, including those related to epigenetic mutations, cellular dysregulation, inflammatory processes, and oxidative stress.

Methods

A systematic literature review regarding current aspects of endometriosis etiology, genesis and development was performed using the PubMed, Google Scholar, and eLibrary databases. Keywords included endometriosis, etiology, development, genesis, associations and mechanisms. A multilingual search was performed.

Results

Several mechanisms underline the pathophysiological pathways for endometriosis development. Epigenetic mutations, external and internal influences, and chronic conditions have a significant impact on endometriosis development, survival and regulation. Several historically valid theories on endometriosis development were discussed, as well as updated findings.

Conclusion

Despite recent advances, fundamental problems in understanding endometriosis remain unresolved. The identification of unknown circulating epithelial progenitors or stem cells that are responsible for epithelial growth in both the endometrium and endometriotic foci seems to be the next step in solving these questions.

Familial risk for endometriosis and its interaction with smoking, age at menarche and body mass index: a population-based cohort study among siblings

OBJECTIVE

To quantify familial risk of endometriosis among full siblings and examine interactions between family history and smoking, age at menarche or body mass index (BMI).

DESIGN, SETTING AND POPULATION

Population-based nationwide cohort study.

METHODS

Using data from the Korean National Health Insurance and Screening Programme databases on kinship, healthcare utilisation, lifestyle and anthropometrics, we identified 2 109 288 women with full siblings and their environmental risk factors from 2002 to 2018. Familial risks were estimated using Cox proportional-hazards models, represented as incidence risk ratios (IRR) with 95% CI. Interaction between family history and smoking, age at menarche or BMI were assessed on an additive scale.

MAIN OUTCOME MEASURES

IRR of endometriosis among women with and without affected siblings.

RESULTS

From 19 195 women with affected siblings, 1126 developed endometriosis with an incidence of 35.45/10 000 person-years. Familial risk of endometriosis with versus without affected siblings was increased to IRR 2.75 (95% CI 2.25-3.36), and the highest risk was with affected twins (IRR 6.98; 95% CI 4.19-11.62). Women with both a family history and either smoking, early menarche or low BMI had a significantly higher risk of endometriosis compared with the general population and can be regarded as a high-risk group, the IRRs were 4.28 (95% CI 2.43-7.55), 3.47 (95% CI 2.82-4.26) and 3.09 (95% CI 2.68-3.56), respectively. Substantial effect modification of the associations was noted by smoking and early menarche, as their combined risk with family history exceeded the sum of their individual risks, which was also statistically significant.

CONCLUSION

Genetic factors are the primary contributor to the familial aggregation of endometriosis. Significant gene-environment interaction exists between family history and smoking or early menarche.

Number needed to freeze: cumulative live birth rate after fertility preservation in women with endometriosis

RESEARCH QUESTION

How does the number of oocytes used affect the cumulative live birth rate (CLBR) in endometriosis patients who had their oocytes vitrified for fertility preservation?

DESIGN

Retrospective observational study including data from 485 women with endometriosis who underwent fertility preservation from January 2007 to July 2018. Survival curves and Kaplan-Meier plots were used to analyse the CLBR according to the number of vitrified oocytes used. Endometriosis curves were compared with plots developed using elective fertility preservation (EFP) patients as control group. Log-rank, Breslow and Tarone-Ware tests were used to compare the survival curves.

RESULTS

The CLBR increased as the number of oocytes used per patient rose, reaching 89.5% (95% confidence interval [CI] 80.0-99.1%) using 22 oocytes. Higher outcomes were observed in young women (≤35 years old versus >35 years old). In the younger group, the CLBR was 95.4% (95% CI 87.2-103.6%) using approximately 20 oocytes versus 79.6% (95% CI 58.1-101.1%) in older women (log-rank [Mantel-Cox] P = 0.002). The mean age was higher in EFP patients (37.2 ± 4.9 versus 35.7 ± 3.7; P < 0.001). The outcome was better in the endometriosis group as compared with EFP: a CLBR of 89.5% (95% CI 80.0-99.1%) versus 59.9% (95% CI 51.4-68.6%) when 22 oocytes were used (log-rank [Mantel-Cox] P < 0.00001).

CONCLUSION

The probability of live birth increases as the number of oocytes used increases in patients with endometriosis, but better outcomes were observed among young women. The information provided here may be of interest to both patients and treating physicians for counselling purposes.

Differential expression of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrium in ovarian endometriomas and their correlations with clinicopathological variables

BACKGROUND

Endometriosis is an estrogen-dependent inflammatory disease that often causes infertility and chronic pelvic pain. Although endometriosis is known as a benign disease, it has demonstrated characteristics of malignant neoplasms, including neoangiogenesis, tissue invasion, and cell implantation to distant organs. Octamer-binding protein 4 (Oct-4) is a molecular marker for stem cells that plays an essential role in maintaining pluripotency and self-renewal processes in various types of benign and malignant tissues. CD44 is a multifunctional cell surface adhesion molecule that acts as an integral cell membrane protein and plays a role in cell-cell and cell-matrix interactions. E-cadherin is an epithelial cell-cell adhesion molecule that plays important role in the modulation of cell polarization, cell migration, and cancer metastasis. The aim of this study was to investigate the expression patterns of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrial tissues from women with endometrioma compared to control endometrial tissues from women without endometrioma.

METHODS

In the present study, Oct-4, CD44, and E-cadherin expressions were evaluated in eutopic and ectopic endometrial tissue samples from women with endometrioma (n = 32) and compared with those of control endometrial tissue samples from women without endometrioma (n = 30).

RESULTS

Immunohistochemical expression of Oct-4 was significantly higher in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0002). Conversely, CD44 and E-cadherin expressions were significantly lower in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0137 and p = 0.0060, respectively). Correlation analysis demonstrated significant correlations between Oct-4 expression and endometrioma cyst diameter (p = 0.0162), rASRM stage (p = 0.0343), and total rASRM score (p = 0.0223). Moreover, CD44 expression was negatively correlated with the presence of peritoneal endometriotic lesions (p = 0.0304) while E-cadherin expression was negatively correlated with the presence of deep infiltrating endometriosis (p = 0.0445).

CONCLUSIONS

Increased expression of Oct-4 and decreased expression of adhesion molecules in endometriotic tissues may contribute to the development and progression of endometriosis.

Immunoregulatory protein V-set and immunoglobulin domain-containing 4 is overexpressed in patients with endometriosis

AIM

V-set and immunoglobulin domain-containing 4 (VSIG4) is a potent negative regulator of T-cell responses and is suggested to regulate antitumor immunity. This study investigates whether VSIG4 is significantly expressed in endometriosis patients and the association between VSIG4 levels and serum cancer antigen (CA)-125 levels, VSIG4 levels and endometriosis severity.

METHODS

Tumor tissues and peripheral blood samples were obtained during surgery from 42 endometriotic cyst and 21 nonendometriotic tumor patients. The levels of VSIG4 mRNA, VSIG4 protein expression in tumor tissue and serum soluble VSIG4 concentration were compared between the two groups. After dividing the cohort using the optimized cut-off values obtained by receiver operating characteristic curve analysis, we examined the association between VSIG4 levels and serum CA-125 levels, VSIG4 levels and the factors indicating endometriosis severity.

RESULTS

The expressions of VSIG4 mRNA, VSIG4 protein and serum VSIG4 concentration were significantly increased in the endometriotic cyst group compared with the control group (P = 0.001, 0.002 and 0.049, respectively). The optimized VSIG4 cut-off values for endometriosis prediction were 0.71, 0.32 and 144.37 pg/mL, respectively. After cohort division using these values, high VSIG4 levels group showed significantly elevated CA-125 compared with low VSIG4 level group (P = 0.010, 0.043 and 0.039, respectively). There was no association between VSIG4 levels and the factors indicating endometriosis severity.

CONCLUSION

The expression of VSIG4 in endometriosis patients is increased compared with nonendometriotic tumor patients, and higher VSIG4 levels are significantly associated with higher serum CA-125 levels. VSIG4 may be importantly involved in the immunological alteration of endometriosis.

Fallopian tube endometriosis in women undergoing operative video laparoscopy and its clinical implications

OBJECTIVE

To determine the incidence of fallopian tube endometriosis in patients undergoing laparoscopic surgery with a preoperative diagnosis of endometriosis, pelvic pain, infertility, or cystic adnexal mass.

DESIGN

Retrospective cross-sectional study.

SETTING

Gynecologic oncology and minimally invasive surgery practice.

PATIENT(S)

All patients who underwent surgery for endometriosis from July 2015 to June 2018 were included. Exclusion criteria were age ≥55 years, diagnosis of cancer, laparotomy, previous bilateral salpingectomy, and preoperative diagnosis other than endometriosis, pelvic pain, infertility, or cystic adnexal mass.

INTERVENTION(S)

Subjects were divided by those who did and those who did not have a salpingectomy at the time of surgery.

MAIN OUTCOME MEASURE(S)

Diagnosis of tubal endometriosis was based on macroscopic evidence of endometrial implants on the fallopian tube(s) noted within the operative report and microscopic evidence of endometriosis noted within the pathology report.

RESULT(S)

A total of 444 surgeries were performed and 185 met the study criteria. Among those, 153 (82.7%) had histologically diagnosed endometriosis within the abdominopelvic cavity. The incidence of tubal endometriosis was 11%-12% macroscopically and 42.5% microscopically after salpingectomy. Patients with tubal endometriosis were more likely to have severe disease.

CONCLUSION(S)

Among patients with endometriosis, the incidence of microscopic tubal endometriosis was significantly greater than that of macroscopic disease.

Hepatocyte nuclear factor-1 beta protects endometriotic cells against apoptotic cell death by up-regulating the expression of antiapoptotic genes†

The overexpression of hepatocyte nuclear factor-1 beta (HNF1β) in endometriotic lesion has been demonstrated. However, the role of HNF1β in endometriosis remains largely unknown. Human endometriotic 12Z cells showed higher level of HNF1β when compared with normal endometrial HES cells. In human endometriotic 12Z cells, HNF1β knockdown increased susceptibility to apoptotic cell death by oxidative stress, while HNF1β overexpression suppressed apoptosis. In addition, HNF1β knockdown and overexpression significantly decreased and increased, respectively, the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-dependent antiapoptotic genes. Knockdown of the antiapoptotic genes significantly reduced the HNF1β-induced resistance against oxidative stress in 12Z cells. Furthermore, HNF1β regulated the transcriptional activity of NF-κB, and an NF-κB inhibitor suppressed the HNF1β-enhanced NF-κB-dependent antiapoptotic gene expression and the resistance of the 12Z cells against cell death. Taken together, these data suggest that HNF1β overexpression may protect endometriotic cells against oxidative damage by augmenting antiapoptotic gene expression.

Endometriosis Malignant Transformation Review: Rhabdomyosarcoma Arising From an Endometrioma

Background:

Endometriosis is a widely known benign disease, but 0.5%–1% of cases are associated with malignancy. It has been linked with ovarian neoplasms, particularly endometrioid and clear cell adenocarcinoma histology. Rhabdomyosarcomas are rarely associated with endometriosis.

Case:

A 35-year-old patient underwent surgical management of endometriomas to optimize infertility treatment. She later developed abdominal pain with rapid recurrence of ovarian masses. This prompted additional surgery with biopsies diagnosing ovarian rhabdomyosarcoma. Retroactive review of pathologic specimens from her prior surgery demonstrated the neoplasm originated from her prior endometrioma. Focal areas suggested possible underlying ovarian adenosarcoma with stromal overgrowth.

Discussion:

The incidence of rhabdomyosarcoma arising from endometriosis is exceedingly rare. The accuracy of diagnosing endometriosis and ruling out neoplasm requires coordinated efforts of a multidisciplinary team, involving radiologists, pathologists, oncologists, and gynecologic surgeons.

A Systematic Review and Bioinformatics Study on Genes and micro-RNAs Involving the Transformation of Endometriosis into Ovarian Cancer

BACKGROUND

Along with the description of tumorigenesis processes in endometriosisrelated ovarian cancer, identifying dysregulated miRNAs, the target genes of these miRNAs, and the processes abnormally affected by dysregulated miRNAs is essential, which was our goal.

METHODS

Two reviewers individually evaluated the articles which collected relevant information including genes and miRNAs involved in the transformation of endometriosis into ovarian cancer. To assess the mature sequence of miRNAs and also their chromosomal positions, miRPathDB software was employed. To determine the main target gene predicted for each considered miRNAs, the TargetScanS Web server was applied. The interaction of each gene with other genes associated with endometrial- related ovarian cancer was determined by GeneMANIA software. Finally, to design integrated model of miRNAs-targeted genes interaction network, the Cytoscape software was used.

RESULTS

The final number of studies available for analysis was 6 manuscripts including 22 miRNAs described as involved in the transformation of endometriosis into different subtypes of ovarian cancers (14 miRNAs up-regulated and 8 miRNAs down-regulated). Three miRNAs of miR-141 (upregulated), miR-205 (down-regulated), and miR-125b (down-regulated) were revealed as the originator for genetic interactions leading to carcinogenesis. We could show some common loops and pathways including uncontrolled cell proliferation and abnormal apoptosis (mediated by PTEN gene induced by miR-21 and miR-214), and disaggregation and epithelialization (mediated by ZEB1 and ZEB2 genes induced by miR-200).

CONCLUSION

According to our analysis, up-regulation of miR-141 and down-regulation of miR-205 and miR-125b have a central role in transforming endometriosis to ovarian cancer.

Accuracy of Clinical Signs and Symptoms in the Diagnosis of Endometriosis

Endometriosis is a benign gynecological disease afffecting about 10% of all reproductive-age women which can significantly impair quality of life. As the clinical presentation is variable, with some women experiencing several severe symptoms while others remain asymptomatic, there are no sufficiently sensitive and specific signs and symptoms or diagnostic tests for the clinical diagnosis of endometriosis. The aim of this article is to review the current literature regarding the accuracy of clinical signs and symptoms in the diagnosis of endometriosis. Besides the wide spectrum of symptoms, an overlap with other causes of pelvic pain such as irritable bowel syndrome and pelvic inflammatory disease is also reported. Moreover, most of the signs and symptoms of endometriosis do not correlate with the severity (staging) of the disease. Knowledge of the characteristics of pelvic pain symptoms is important in the preoperative assessment of patients with suspected endometriosis. Pelvic tenderness, a fixed retroverted uterus, tender uterosacral ligaments or enlarged ovaries identified during a standard pelvic exam are suggestive of endometriosis. Clinical examination during menstruation apparently improves diagnostic yield. Although the clinical diagnosis of endometriosis presents low sensitivity and specificity, it should be thoroughly performed as it is the first fundamental step in the diagnostic workup. Clinical assessment helps to identify patients at high risk of endometriosis and selects those who need further testing in order to reduce diagnostic delay. Laparoscopy preferably performed in conjunction with histologic evaluation of excised lesions, however, still remains the gold standard for diagnosis as well as staging of endometriosis.

p27kip1 as a key regulator of endometriosis

p27^kip1 as a key regulator of endometriosis Gonçalves GA p27^kip1 is a cyclin-dependent kinase (CDK) inhibitor whose specific late G1 destruction allows progression of the cell across the G1/S boundary. There is a direct relationship between low level of p27 and rapid proliferation occurring in several benign states and in many malignances. In the glandular cells of the normal endometrium, the level of p27^kip1 is exceedingly low during the proliferative phase, whereas it is markedly increased during the secretory phase. The expression of p27^kip1 in endometriosis is very low but has been found to increase following treatment with progesterone. However, estrogen exposure is considered as a major risk factor in developing endometrial cancer. Endometriosis endometrial cells cultures have also lower levels of p27^kip1 compared to heath endometrial cells cultures and restore the cell cycle balance when transduced with an adenoviral vector carring the p27^kip1 coding gene (Adp27EGFP). More uniform and rigorous studies are required to confirm these and additional markers utility in a diagnostic and possible treatment panel. As a major clinical priority is to determine which lesions can be treated medically and which require surgical intervention, focusing future studies on markers that distinguish response to hormone therapy or are involved in hormone regulation, will be important future considerations. The goal of this highlight review is to provide a broad overview of the advancements in studies about endometriosis mainly correlating the cytokine p27^kip1 expression with the diagnostic and disease treatment.

Effect of simvastatin on monocyte chemoattractant protein-1 expression in endometriosis patients: a randomized controlled trial

Background

Simvastatin is a promising new drug for the treatment of endometriosis. It is a cholesterol-lowering drug that acts by inhibiting HMG-CoA reductase, resulting in a decrease in mevalonate, a precursor of cholesterol and monocyte chemoattractant protein-1 (MCP-1). This study investigated the effect of pre-operative oral simvastatin administration on MCP-1 gene expression and serum MCP-1 protein levels in patients with endometriosis.

Methods

A prospective, randomized, controlled study was conducted at the Reproductive Endocrinology Unit of the Department of Obstetrics and Gynecology at the Faculty of Medicine Ramathibodi Hospital. Forty women (mean age: 18–45 years) scheduled for laparoscopic surgery who had been diagnosed with endometriosis were recruited and randomly assigned to either a treatment group (20 mg/d of orally administered simvastatin for 2 weeks before surgery) or an untreated control group. Serum was collected before and after treatment and protein levels of MCP-1 were determined. MCP-1 and CD68 transcript levels were also quantified using real-time PCR on endometriotic cyst tissues.

Results

MCP-1 gene expression on endometriotic cyst was not significantly different between the simvastatin-treated and untreated groups (P = 0.99). CD68 expression was higher in the treatment group compared to the control group, but this was not statistically significant (P = 0.055). Serum MCP-1 levels following simvastatin treatment were higher than in samples obtained before treatment (297.89 ± 70.77 and 255.51 ± 63.79 pg/ml, respectively) (P = 0.01).

Conclusions

Treatment with 20 mg/d of simvastatin for 2 weeks did not reduce the expression of either the chemokine MCP-1 gene or macrophage-specific genes. Cumulatively, this suggests that simvastatin is not ideal for treating endometriosis because a higher dose of simvastatin (40–100 mg/d) would be needed to achieve the target outcome, which would significantly increase the risk of myopathy in patients.

Trial registration

Thai Clinical Trials Registry TCTR20130627003 Registered: June 27, 2013.

Role of Interleukin-6 and Its Receptor in Endometriosis

Background

Studies have shown that the concentration of interleukin (IL)-6 in peritoneal fluid is increased in patients with endometriosis; however, whether the disorders involving IL-6 contribute to the development of endometriosis is still unclear. In the present study, we evaluated the potential role of IL-6 and IL-6 receptor (IL-6R) in the pathogenesis of endometriosis.

Material/Methods

We examined activated macrophages and the expression of membrane-binding receptor (mIL-6R) in peritoneal fluid using flow cytometry. The levels of IL-6 and the IL-6 soluble receptor (sIL-6R) in peritoneal fluid and plasma in patients with endometriosis was measured by an enzyme-linked immunosorbent assay.

Results

Activated macrophages and mIL-6R in peritoneal fluid were increased in patients with endometriosis. IL-6 and sIL-6R in peritoneal fluid were also increased in patients with endometriosis; however, there was an increase in plasma IL-6 and a decrease in plasma sIL-6R. The endometriosis group was categorized into 2 groups according to the retrospective American Fertility Society Score (r-AFS): group A and group B. Peritoneal fluid sIL-6R in endometriosis group B was significantly higher than in endometriosis group A and the control group.

Conclusions

Disorders involving IL-6 and IL-6R are correlated with the etiology of endometriosis. An increase in sIL-6R in peritoneal fluid promotes the development of endometriosis by enhancing the bioactivity of IL-6.

Adhesions and endometriosis: challenges in subfertility management : (An expert opinion of the ANGEL-The ANti-Adhesions in Gynaecology Expert PaneL-group)

There is molecular evidence that endometriosis has a negative impact on the ovaries, although the exact pathophysiology concerning endometriosis-associated subfertility is not known. The negative impact on the tubo-ovarian unit can be directly by distorting the anatomy, indirectly by invoking inflammation or by oxidative damage with poorer-quality oocytes. Endometriosis even seems to have a negative effect on pregnancy outcome after in vitro fertilization.

Decreased Cytotoxicity of Peripheral and Peritoneal Natural Killer Cell in Endometriosis

Endometriosis causes significant chronic pelvic pain, dysmenorrhea, and infertility and affects 10% of all women. In endometriosis, ectopic endometrium surviving after retrograde menstruation exhibits an abnormal immune response characterized by increased levels of activated macrophages and inflammatory cytokines. Particularly, dysfunctional natural killer (NK) cells play an important role in the pathogenesis of the disease by either facilitating or inhibiting the survival, implantation, and proliferation of endometrial cells. NK cells in the peritoneum and peritoneal fluid exhibit reduced levels of cytotoxicity in women with endometriosis. Several cytokines and inhibitory factors in the serum and peritoneal fluid also dysregulate NK cell cytotoxicity. Additionally, increased numbers of immature peripheral NK cells and induction of NK cell apoptosis are evident in the peritoneal fluid of women with endometriosis. The high rate of endometriosis recurrence after pharmaceutical or surgical treatment, which is associated with dysfunctional NK cells, indicates that new immunomodulatory management strategies are required. A good understanding of immune dysfunction would enable improvement of current treatments for endometriosis.

Endometriosis-associated Malignancy

Endometriosis is a common condition in women of reproductive age. According to several epidemiological studies endometriosis may be associated with increased risk of various malignancies. However, endometriosis-associated malignancy (EAM) is defined by certain histological criteria. About 80 % of EAM have been found in the ovary, whereas 20 % are localized in extragonadal sites like intestine, rectovaginal septum, abdominal wall, pleura and others. Some authors suggest that EAM arise from atypical endometriosis as an intermediate lesion between endometriosis and cancer. Moreover, a number of genetic alterations, like loss of heterozygosity (LOH), PTEN, ARID1 A and p53 mutations have been found in both endometriosis and EAM. Endometriosis-associated ovarian cancer (EAOC) is mostly a well or intermediately differentiated tumor of endometrioid or clear cell histological sub-type. Women affected by EAOC are on average five to ten years younger than non-EAOC patients; in most of the cases EAOC is a low stage disease with favorable clinical outcome. Since EAM is a rare condition systematic data on EAM are still missing. A systematic retrospective study on endometriosis-associated malignancies (EAM study) is currently being conducted by the Endometriosis Research Foundation together with the study groups on ovarian and uterine tumors of the working group for gynecological oncology (AGO) (gyn@mlk-berlin.de).

Evidence for the Relationship Between Endometriosis and Epithelial Ovarian Cancer

Endometriosis may be a precursor lesion for some epithelial ovarian cancers (EOCs), especially those of clear cell and endometrioid histologies. The causality of this relationship remains controversial and in need of further investigation because the high prevalence of endometriosis and high mortality of EOC carry significant public health implications if the association is real. Endometriosis-associated ovarian cancer (EAOC) often presents at an earlier stage and with lower-grade lesions than non-EAOC. After surgical resection, these patients also tend to have less residual disease than do patients with non-EAOC. Survival has been reported to be better for women with EAOC. The tumor suppression gene, ARID1A, is frequently disrupted in EAOC. The ARID1A mutation has been reported in preneoplastic lesions and may be an early marker in the transformation of endometriosis into cancer. The current evidence in respect to critical molecular pathways underscores the need to investigate possible role of targeted therapies in the treatment of EAOC.

Association of endometriosis and breast cancer: mini review of the literature

BACKGROUND

Endometriosis is a common, estrogen-dependent, gynecological disease, which is defined as the presence of endometrial tissue outside the uterine cavity. Current data have associated endometriosis with specific malignancies, including ovarian and breast cancer.

PURPOSE

The purpose of our study is to summarize and present published literature providing evidence regarding the possible relationship between endometriosis and breast cancer.

METHODS

Pubmed and Scopus databases were searched systematically for studies that sought to identify a potential association of endometriosis and breast cancer. 15 relevant articles were retrieved and included in the present review.

RESULTS

A small number of observational studies have shown a correlation of endometriosis and breast cancer. Other studies found that the risk of breast cancer increases with age. The scenario of an early interruption of the inflammatory process, derived from endometriosis, by oophorectomy and a possible consequent decrease in the risk of breast cancer has also been proposed. The hypothesis that both conditions could be related through common mutations on BRAC1 and BRAC2 genes has also been investigated.

CONCLUSION

The available published evidence is inconclusive. Further studies are needed to evaluate the association of endometriosis and breast cancer and the possible pathogenetic pathways that relate the two disorders.

Endometriosis and ovarian cancer: links, risks, and challenges faced

Endometriosis is a benign gynecological condition characterized by specific histological, molecular, and clinical findings. It affects 5%-10% of premenopausal women, is a cause of infertility, and has been implicated as a precursor for certain types of ovarian cancer. Advances in technology, primarily the ability for whole genome sequencing, have led to the discovery of new mutations and a better understanding of the function of previously identified genes and pathways associated with endometriosis associated ovarian cancers (EAOCs) that include PTEN, CTNNB1 (β-catenin), KRAS, microsatellite instability, ARID1A, and the unique role of inflammation in the development of EAOC. Clinically, EAOCs are associated with a younger age at diagnosis, lower stage and grade of tumor, and are more likely to occur in premenopausal women when compared with other ovarian cancers. A shift from screening strategies adopted to prevent EAOCs has resulted in new recommendations for clinical practice by national and international governing bodies. In this paper, we review the common histologic and molecular characteristics of endometriosis and ovarian cancer, risks associated with EAOCs, clinical challenges and give recommendations for providers.

Comparison of treatment options for experimental endometriosis in rats

The effectiveness of surgery, immunomodulator "Vilon" therapy, and their combination in the treatment of experimental endometriosis in rats was assessed by the parameters of reproductive function. The experiments demonstrated that surgery combined with intraperitoneal application of "Vilon" is a promising option in the treatment of endometriosis.

A potential novel treatment strategy: inhibition of angiogenesis and inflammation by resveratrol for regression of endometriosis in an experimental rat model

The aim of our study was to evaluate the effectiveness of resveratrol in experimentally induced endometrial implants in rats through inhibiting angiogenesis and inflammation. Endometrial implants were surgically induced in 24 female Wistar-Albino rats in the first surgery. After confirmation of endometriotic foci in the second surgery, the rats were divided into resveratrol (seven rats), leuprolide acetate (eight rats), and control (seven rats) groups and medicated for 21 d. In the third surgery, the measurements of mean areas and histopathological analysis of endometriotic lesions, VEGF, and MCP-1 measurements in blood and peritoneal fluid samples, and immunohistochemical staining were evaluated. After treatment, significant reductions in mean areas of implants (p < 0.01) and decreased mean histopathological scores of the implants (p < 0.05), mean VEGF-staining scores of endometriotic implants (p = 0.01), and peritoneal fluid levels of VEGF and MCP-1 (p < 0.01, for VEGF and p < 0.01, for MCP-1) were found in the resveratrol and leuprolide acetate groups. Serum VEGF (p = 0.05) and MCP-1 (p = 0.01) levels after treatment were also significantly lower in the resveratrol and leuprolide acetate groups. Resveratrol appears to be a potential novel therapeutic agent in the treatment of endometriosis through inhibiting angiogenesis and inflammation. Further studies are needed to determine the optimum effective dose in humans and to evaluate other effects on reproductive physiology.

Tubal origin of ovarian endometriosis

Endometriosis is a puzzling and debilitating disease that affects millions of women around the world. Ovary is the most common organ site involved by endometriosis. Despite various hypotheses about its cell of origin, uncertainty remains. On the basis of our clinicopathologic observations, we hypothesize that fallopian tube may contribute the histogenesis of ovarian endometriosis. To examine if the hypothesis, tubal origin of ovarian endometriosis, has scientific supporting evidence, we identified a set of novel genes, which are either highly expressed in the normal fallopian tube or in the endometrium through a gene differential array study. Among many differentially expressed genes, FMO3 and DMBT1 were selected as the initial biomarkers to test the hypothesis. These biomarkers were then validated in ovarian sections with foci of endometriosis by comparing their expression levels in the fallopian tube and the endometrium within the same patients with real-time PCR, western blot and immunohistochemistry analysis. FMO3 was highly expressed in the tubal epithelia while low in the paired endometrium. In contrast, DMBT1 was high in the endometrium but low in the fallopian tube. In 32 ovarian endometriosis cases analyzed by real-time PCR, 18 (56%) showed a high level of FMO3 and a low level of DMBT1 expression. However, 14 (44%) endometriosis cases showed a reversed expression pattern with these two markers. Results were similarly seen in the methods of western blot and immunohistochemistry. The findings suggest that approximately 60% of the ovarian endometriosis we studied may be derived from the fallopian tube, whereas about 40% of the cases may be of endometrial origin. The fallopian tube epithelia may represent one of the tissue sources contributing to ovarian endometriosis. Such novel findings, which require confirmation, may have a significant clinical impact in searching for alternative ways of prevention and treatment of endometriosis.

An increased level of IL-6 suppresses NK cell activity in peritoneal fluid of patients with endometriosis via regulation of SHP-2 expression

STUDY QUESTION

Is the decreased natural killer (NK) cell cytolytic activity in the peritoneal fluid (PF) of endometriosis patients due to primary cytokine activity?

SUMMARY ANSWER

An increased level of interleukin-6 (IL-6) in the PF of patients with endometriosis suppresses NK cell cytolytic activity by down-regulating cytolytic granule components, such as granzyme B and perforin, through the modulation of Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) expression.

WHAT IS ALREADY KNOWN

Endometriosis is known to be related to a defect in NK cell cytolytic activity. Additionally, the levels of inflammatory cytokines are elevated in the PF of women with endometriosis.

STUDY DESIGN, SIZE, DURATION

The effects of PF on the differentiation and functional activity of NK cells were investigated in patients with or without endometriosis, and cytokines that reduce NK cell cytolytic activity in endometriosis patients were examined. The study included women who underwent laparoscopic examination for the diagnosis of endometriosis from August 2012 to July 2013 (33 women with, and 15 women without, endometriosis).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women of reproductive age (20-40 years old) who underwent laparoscopic examination for endometriosis were included. Cytokines present in the PF were identified by enzyme-linked immunosorbent assay. The cytolytic activity of NK cells in the PF was also analyzed using a calcein-acetoxy methyl ester (AM) release assay.

MAIN RESULTS AND THE ROLE OF CHANCE

PF from patients with endometriosis suppressed the differentiation and cytotoxicity of NK cells compared with PF from controls (P < 0.05). Increased levels of IL-6 were also found in the PF of patients with endometriosis (P < 0.01), and IL-6 levels were negatively correlated with the cytolytic activity of NK cells (rs = -0.558, P = 0.03). Furthermore, IL-6 reduced the cytolytic activity of NK cells, concomitantly with the down-regulation of granzyme B and perforin (P < 0.05), by modulating SHP-2. Importantly, the addition of anti-IL-6 to the PF of endometriosis patients restored the activity of NK cells (P < 0.01), suggesting that IL-6 plays a crucial role in the reduction of NK cell activity in the PF of patients with endometriosis.

LIMITATIONS, REASONS FOR CAUTION

PF contains various inflammatory cytokines in addition to IL-6 and so it is possible that other cytokines may affect the differentiation and activity of NK cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our results imply that the suppression of IL-6 using an anti-IL-6 antibody or soluble IL-6 receptor could rescue the impairment of NK cell activity in patients with endometriosis.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the KRIBB Creative Research Program (KCS3051312); the STP project (DTM0111221) of the Ministry of Knowledge & Economy and the Basic Science Research Program (RBM0271312) of the National Research Foundation of Korea (NRF) from the Ministry of Education, Science & Technology. There are no conflicts of interest.

Endometriosis and ovarian cancer risk: a systematic review of epidemiological studies

Background: A possible etiological association between endometriosis and ovarian cancer has been repeatedly reported in the literature.

Objective: Our aim was to evaluate published epidemiological data on this issue.

Review Methods: We conducted an extensive search of the literature in MEDLINE, of articles ever published until February 2014, using the key-words “endometriosis” and “ovarian” and one of the following terms in the title: “cancer” or “malignancy” or “malignant” or “tumor” or “neoplasia” or “neoplasm” or “transformation.” Retrieved papers were checked for further relevant publications.

Results: Overall, our search yielded 1 prospective cohort study, 10 retrospective cohort, and 5 case–control studies. A meta-analysis of these studies was not considered to be appropriate, due to differences in data reporting, study design, and adjustment for confounding factors.

Limitations: The main limitation of studies found, with one exception, was the lack of operative confirmation of endometriosis.

Conclusion: An association of endometriosis with clear-cell and endometrioid ovarian cancer was a consistent finding in most studies. On the other hand, existing epidemiological evidence linking endometriosis with ovarian cancer is insufficient to change current clinical practice. Prospective cohort studies, with prior laparoscopic confirmation, localization, and staging of endometriosis are needed, in order to further clarify this issue.

The Link Between Endometriosis and Ovarian Cancer: Clinical Implications

Objectives

The objectives of this study were to evaluate the current evidence of the association of endometriosis and subsequent carcinoma of the ovary and to contextualize this evidence into daily practice issues.

Methods

This study is a critical review of observational and in vitro studies.

Results

Although the lifetime risk for ovarian cancer is low in general population and remains low in the broad spectrum of endometriosis, there may be clusters of individuals at higher risk of oncogenesis, whose identification would allow individualized surveillance and prophylactic interventions. Prevalence studies show that specific subtypes of ovarian cancer predominate in women with endometriosis. This has been validated in pathogenetic, genomic, immunobiologic, and hormonal studies.

Conclusions

Taken together, these data provide a strong rationale for identifying, monitoring, counseling, and treating women with endometriosis who are at highest risk for cancer conversion.

Immunology of normal and abnormal menstruation

Normal menstruation is an inflammatory process, where the endometrial concentrations and functions of several leukocyte types can change greatly through the menstrual cycle, especially during the premenstrual and menstrual phases. These leukocytes probably have a range of functions related to mucosal protection, decidualization, embryo implantation, and the process of menstrual tissue breakdown, repair and remodeling. Some of these leukocyte changes are apparently linked to changes in the pattern of circulating leukocytes. Many immune cells have been identified in the endometrium, and those with most relevance to the processes of menstruation include uterine natural killer cells, macrophages, mast cells, neutrophils, dendritic cells and Tregs. A range of disturbances in endometrial immune cell numbers, distributions and functions, and in a range of different inflammatory and other mediators, have been identified in women with heavy menstrual bleeding or endometriosis. Sufficient evidence exists to implicate these immune changes in some of the functional disturbances and symptoms identified in these women. This field is greatly under-researched, and ripe for the wider application of modern molecular and cellular techniques in human and animal model studies.

The relation between endometriosis and ovarian cancer - a review

BACKGROUND

Endometriosis is known to harbor characteristics substantiating its possible role as a precursor of ovarian cancer.

OBJECTIVE

To assess the quality of the literature regarding the association between endometriosis and ovarian cancer and to estimate the extent of this relation.

METHODS

An electronic literature search was conducted in PubMed and 1112 articles dealing with the relation between endometriosis and ovarian cancer were identified. Original articles based on case-control studies, cohort studies and cross-sectional studies were included. Studies consisting of populations with self-reported endometriosis were excluded, as were articles with fewer than 20 cases of ovarian cancer. Twenty-eight studies underwent detailed quality assessments based on the checklists developed by the Scottish Intercollegiate Guidelines Network (SIGN). Meta-analyses were conducted on selected subgroups of ovarian cancer with coexisting endometriosis.

RESULTS

None of the 28 studies was given the highest possible rating using the SIGN checklists. The risk of ovarian cancer in women with endometriosis was reported to be a standardized incidence ratio of 1.43-8.95, a rate ratio of 1.6-2.88, an odds ratio of 1.34, with a prevalence of ovarian cancer in 2.0-17.0% of women with endometriosis. Conversely, the prevalence of endometriosis in women with ovarian cancer ranged from 3.4 to 52.6%. Meta-analysis results were weakened by heterogeneity.

CONCLUSION

There is sufficient evidence to conclude that there is an increased risk of developing clear-cell and endometrioid epithelial ovarian cancer for women with histologically verified endometriosis. Nonetheless, prospective cohort studies assessing the relation between endometriosis and ovarian cancer will increase knowledge in this field.

Cellular, histologic, and molecular changes associated with endometriosis and ovarian cancer

Our understanding of the pathogenesis of endometriosis is rapidly evolving as early molecular events are increasingly identified. Endometriosis is associated with increased risk of ovarian cancer and exhibits neoplastic phenotypes including invasion of stromal tissue and lymphatic spread to distant organs. This review of the literature establishes the clinical, epidemiologic, and pathologic correlation between endometriosis and low-grade ovarian cancer. Genetic studies have demonstrated that endometriotic lesions have mutations in genes directly related to neoplasms, in particular the p53, KRAS, PTEN, and ARID1A genes, which suggests a direct transition from a subset of endometriotic lesions to invasive carcinomas. The identification of both genetic and epigenetic biomarkers including microRNAs are essential for identifying patients at risk for the transition to neoplasia.

IL-1 receptor 2 (IL-1R2) and its role in immune regulation

The cytokine IL-1 is critical to the pathogenesis of a variety of human conditions and diseases. Unlike most other cytokines, IL-1 is counterbalanced by two endogenous inhibitors. The functional significance of IL-1 receptor antagonist (IL-1RA) is well documented due to the clinical utilization of the recombinant human IL-1RA analog, anakinra. In contrast, much less is known about the type 2 IL-1 receptor (IL-1R2), which acts as a decoy receptor for IL-1. While IL-1R2 is structurally similar to the type 1 IL-1 receptor (IL-1R1) responsible for IL-1 signal transduction, its truncated cytoplasmic domain and lack of Toll-IL-1 receptor (TIR) region renders IL-1R2 incapable of transmembrane signaling. IL-1R2 competes with IL-1R1 for ligands and for the IL-1R1 co-receptor, IL-1 receptor accessory protein (IL-1RAP). Additionally, IL-1R2 exists in both a membrane bound and soluble form (sIL-1R2) that has biological properties similar to both a decoy receptor and a binding protein. Thus far, IL-1R2 has been implicated in arthritis, endometriosis, organ transplantation, sepsis/sickness behavior, diabetes, atherosclerosis, autoimmune inner ear disease (AIED), Alzheimer's disease and ulcerative colitis. In this review, we will detail the functional properties of IL-1R2 and examine its role in human disease.

Endometriosis-associated ovarian cancer: a review of pathogenesis

Endometriosis is classically defined as the presence of endometrial glands and stroma outside of the endometrial lining and uterine musculature. With an estimated frequency of 5%–10% among women of reproductive age, endometriosis is a common gynecologic disorder. While in itself a benign lesion, endometriosis shares several characteristics with invasive cancer, has been shown to undergo malignant transformation, and has been associated with an increased risk of epithelial ovarian carcinoma (EOC). Numerous epidemiologic studies have shown an increased risk of EOC among women with endometriosis. This is particularly true for women with endometrioid and clear cell ovarian carcinoma. However, the carcinogenic pathways by which endometriosis associated ovarian carcinoma (EAOC) develops remain poorly understood. Current molecular studies have sought to link endometriosis with EAOC through pathways related to oxidative stress, inflammation and hyperestrogenism. In addition, numerous studies have sought to identify an intermediary lesion between endometriosis and EAOC that may allow for the identification of endometriosis at greatest risk for malignant transformation or for the prevention of malignant transformation of this common gynecologic disorder. The objective of the current article is to review the current data regarding the molecular events associated with EAOC development from endometriosis, with a primary focus on malignancies of the endometrioid and clear cell histologic sub-types.

Physical therapy and psychological intervention normalize cortisol levels and improve vitality in women with endometriosis

There is as yet no effective treatment for endometriosis. The objective of this study was to evaluate the effectiveness of submitting women with endometriosis and chronic pelvic pain to a therapeutic protocol involving physical and psychological therapy. Twenty-six female volunteers were submitted to a treatment protocol consisting of 2.5-h sessions, once a week for 10 weeks. We applied a Visual Analogue Scale, the Perceived Stress Questionnaire (PSQ), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Morning, afternoon, and evening levels of cortisol were determined in saliva samples. The PSQ scores were significantly lower after treatment, whereas the scores for the SF-36 vitality and physical functioning domains were significantly higher. Salivary cortisol levels were higher after treatment in the samples collected in the morning, but not in those collected in the afternoon or evening. The post-treatment cortisol levels were similar to those reported for healthy women. There were positive correlations between vitality, role emotional, social functioning, and mental health, and negative correlations to perceived stress. In conclusion, the physical and psychological intervention protocol applied in this study to women suffering of endometriosis was effective in reducing perceived stress, normalizing cortisol levels, increasing vitality and improving physical functioning.

In vitro model of stromal and epithelial immortalized endometriotic cells

Endometriosis is a relatively common chronic gynecologic disorder that usually presents with chronic pelvic pain or infertility. It results from implantation of endometrial tissue outside the uterine cavity. Despite its frequency and its impact on quality of life, the understanding of pathogenesis of endometriosis remains incomplete and its treatment remains controversial. In this work, we established a suitable in vitro model system of immortalized human endometriotic cell line taking advantage of the human telomerase reverse transcriptase. The results demonstrate that these cells retain the natural characteristics of endometrial cells in term of phenotype and of functional expression of estrogen and progesterone receptors, without chromosomal abnormalities. In conclusion, these cells are potentially useful as an experimental model to investigate endometriosis biology.

Endostatin Gene Therapy for Endometriosis in Rats

Objective:

Endostatin gene therapy for endometriosis was studied in an experimental autotransplantation model in rats.

Methods:

Endometriotic lesions were transfected by intralesional injection of the plasmid lipofectamine-endostatinpBud (group 1), lipofectamine-pBud (empty vector; group 2) or phosphatebuffered saline (group 3). Endostatin mRNA and protein levels in lesions were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and Western blot analysis. Endostatin and vascular endothelial growth factor (VEGF) protein levels in serum, and microvessel density (MVD) and matrix metalloproteinase (MMP)-2 protein levels in endometriotic lesions, were also determined.

Results:

Lipofectamine- endostatin-pBud injection increased endostatin mRNA and protein levels in lesions. Lesions were significantly smaller, and serum VEGF levels significantly lower, in group 1 versus controls. Serum VEGF was significantly and negatively correlated with serum endostatin. In group 1, MMP-2 levels and MVD were significantly lower versus controls. MMP-2 level was negatively correlated with endostatin.

Conclusions:

Gene therapy with endostatin appears to be an effective treatment for endometriosis. Restoration of endostatin gene expression by gene transfer in vivo might be a potential gene therapy approach for human endometriosis.

Expression of ghrelin and its receptors in ovarian endometrioma

Endometriosis is a common gynaecological disorder manifesting by implantation and growth of endometrial tissue outside the uterine cavity. The evidence accumulates that endometriosis may be associated with abrogated regulation of energy balance. Ghrelin is one of the most important orexigenic factor which may also play a role in regulation of inflammatory and angiogenic reactions. The present study was aimed at investigating expression profile of ghrelin and its receptors (GHSR1α and GHSR1β) in endometriotic lesions. The study included ovarian cysts and peritoneal fluid specimens obtained laparoscopically from 20 women with revised American Fertility Society stage III or IV endometriosis. Expression of specific mRNAs was assessed by reverse transcription-polymerase chain reaction. Expression of ghrelin and GHSR1α protein was studied by immunohistochemical staining with specific antibodies. Ghrelin and its receptors mRNA expression was found in all tested specimens. Specific mRNAs for these factors were also expressed in the peritoneal leukocytes. Immunohistochemical staining revealed expression of ghrelin and GHSR1α both in glandular endometrioid epithelium and in some stromal cells, particularly in some fibroblasts, blood vessels and infiltrating leukocytes. Co-localization of ghrelin and its receptors strongly suggests that this neuropeptide may affect development and growth of endometriotic lesions and may influence local inflammatory and angiogenic response.

Imbalance between sympathetic and sensory innervation in peritoneal endometriosis

To investigate possible mechanisms of pain pathophysiology in patients with peritoneal endometriosis, a clinical study on sensory and sympathetic nerve fibre sprouting in endometriosis was performed. Peritoneal lesions (n=40) and healthy peritoneum (n=12) were immunostained and analysed with anti-protein gene product 9.5 (PGP 9.5), anti-substance P (SP) and anti-tyrosine hydroxylase (TH), specific markers for intact nerve fibres, sensory nerve fibres and sympathetic nerve fibres, respectively, to identify the ratio of sympathetic and sensory nerve fibres. In addition, immune cell infiltrates in peritoneal endometriotic lesions were analysed and the nerve growth factor (NGF) and interleukin (IL)-1β expression was correlate with the nerve fibre density. Peritoneal fluids from patients with endometriosis (n=40) and without endometriosis (n=20) were used for the in vitro neuronal growth assay. Cultured chicken dorsal root ganglia (DRG) and sympathetic ganglia were stained with anti-growth associated protein 43 (anti-GAP 43), anti-SP and anti-TH. We could detect an increased sensory and decreased sympathetic nerve fibres density in peritoneal lesions compared to healthy peritoneum. Peritoneal fluids of patients with endometriosis compared to patients without endometriosis induced an increased sprouting of sensory neurites from DRG and decreased neurite outgrowth from sympathetic ganglia. In conclusion, this study demonstrates an imbalance between sympathetic and sensory nerve fibres in peritoneal endometriosis, as well as an altered modulation of peritoneal fluids from patients with endometriosis on sympathetic and sensory innervation which might directly be involved in the maintenance of inflammation and pain.

Endometriosis and ovarian cancer: a review of clinical, pathologic, and molecular aspects

Endometriosis is a chronic disease that affects millions of reproductive-age women. Despite the destructive and invasive nature of endometrioses, most cases are perpetually benign or eventually regress; however, atypical endometriosis is a precursor lesion and can lead to certain types of ovarian cancer. Endometriosis induced inflammation and auto- and paracrine production of sex steroid hormones contribute to ovarian tumorigenesis. These changes provide microenvironment necessary to accumulate enough genetic alterations for endometriosis associated malignant transformation. It takes years for endometriosis to undergo the pathophysiological progression that begins with atypical epithelial proliferation (atypical endometriosis and metaplasia), and then is followed by the formation of well-defined borderline tumors, and finally culminates in fully malignant ovarian cancer. This study is a review of the natural history of endometriosis and the role of microenvironments that favor the accumulation of genetic alterations and endometriosis-associated ovarian cancer progression.

The association between endometriosis and ovarian cancer: a review of histological, genetic and molecular alterations

OBJECTIVE

This article represents a review of histologic and genetic findings in endometriosis and describes the mechanisms whereby genetic and non-genetic factors potentially contribute to the neoplastic progression of endometriosis.

METHODS

Literature review of the English language literature based on searching in the MEDLINE (PubMed) database and additional collection of reports by systematically reviewing all references from retrieved papers.

RESULTS

Atypical endometriosis seems to represent a transition from benign endometriosis to carcinoma. Endometriosis is characterized by genetic instability: like neoplasms endometriosis seems to be monoclonal in origin, several studies have documented loss of heterozygosity (LOH) in endometriosis, data suggest that mutation of the tumor suppressor gene PTEN play a part in the malignant transformation of endometriosis, some studies have revealed TP53 mutations in endometriotic lesions, and mutation of ARID1A seems to be an important early event in the malignant transformation of endometriosis to endometrioid and clear cell carcinomas. Heme and iron induced oxidative stress, inflammation, and hyperestrogenism are possible links between endometriosis and cancer.

CONCLUSIONS

The histological and genetic alterations in endometriosis seem to explain why endometriosis can be a precursor of some ovarian cancers, especially clear cell and endometrioid carcinomas. However, the exact molecular mechanisms that may lead to this malignant transformation of endometriosis are not completely understood. More and larger studies are needed to clarify how exactly endometriotic tissue undergoes malignant transformation.

Increased levels of human neutrophil peptides 1, 2, and 3 in peritoneal fluid of patients with endometriosis: association with neutrophils, T cells and IL-8

Endometriosis is a common gynaecological disorder characterized by the presence of endometrial tissue outside the uterine cavity. This disease is associated with pelvic inflammation and displays some features of autoimmune disorder. Human neutrophil peptides 1, 2, and 3 (HNP 1-3) belonging to α-defensin family play a crucial role in innate immunity against infections and may exert immunoregulatory effects. They may play a role in various inflammatory reactions; however, their role in endometriosis has not been studied. Therefore, the aim of the present study was to evaluate HNP 1-3 in the peritoneal fluid of 67 patients with endometriosis and 16 healthy control women in relation to peritoneal leukocyte subpopulations (neutrophils, T cells, and macrophages) and inflammatory cytokines (IL-6 and IL-8). HNP 1-3, IL-6 and IL-8 were evaluated in the peritoneal fluid by specific enzyme-linked immunosorbent assays (ELISA), and peritoneal leukocyte subpopulations were evaluated by flow cytometry. We found that the levels of HNP 1-3 were significantly increased in the peritoneal fluid of endometriosis patients, compared with control women, and correlated with severity of the disease. Endometriosis was also associated with increased concentrations of peritoneal neutrophils. In endometriosis the levels of HNP 1-3 strongly correlated with concentrations of neutrophils, T cells and IL-8. HNP 1-3 levels were not associated with peritoneal IL-6 or macrophages. These data suggest that HNP 1-3 and neutrophils might play a role in immunopathogenesis of endometriosis and may be worth evaluating as targets for anti-endometriosis therapy.