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

CircFOXO3 mediates hypoxia-induced autophagy of endometrial stromal cells in endometriosis

Endometriosis is a benign gynecological disease that shares some common features of malignancy. Autophagy plays vital roles in endometriosis and influences endometrial cell metastasis, and hypoxia was identified as the initiator of this pathological process through hypoxia inducible factor 1 alpha (HIF-1α). A newly discovered circular RNA FOXO3 (circFOXO3) is critical in cell autophagy, migration, and invasion of various diseases and is reported to be related to hypoxia, although its role in endometriosis remains to be elucidated up to now. In this study, a lower circFOXO3 expression in ectopic endometrium was investigated. Furthermore, we verified that circFOXO3 could regulate autophagy by downregulating the level of p53 protein to mediate the migration and invasion of human endometrial stromal cells (T HESCs). Additionally, the effects of HIF-1α on circFOXO3 and autophagy were examined in T HESCs. Notably, overexpression of HIF-1α could induce autophagy and inhibit circFOXO3 expression, whereas overexpressing of circFOXO3 under hypoxia significantly inhibited hypoxia-induced autophagy. Mechanistically, the direct combination between HIF-1α and HIF-1α-binding site on adenosine deaminase 1 acting on RNA (ADAR1) promoter increased the level of ADAR1 protein, which bind directly with circFOXO3 pre-mRNA to block the cyclization of circFOXO3. All these results support that hypoxia-mediated ADAR1 elevation inhibited the expression of circFOXO3, and then autophagy was induced upon loss of circFOXO3 via inhibition of p53 degradation, participating in the development of endometriosis.

Network Pharmacology Was Used to Predict the Active Components and Prospective Targets of Paeoniae Radix Alba for Treatment in Endometriosis

Endometriosis is one of the most common benign gynecologic diseases. Paeoniae Radix Alba (PRA) has been utilized to treat endometriosis. We wished to identify potential targets for PRA in the treatment of endometriosis, as well as to provide a groundwork for future studies into its pharmacological mechanism of action. Network pharmacology was employed to conduct investigations on PRA. Target proteins were chosen from the components of PRA for endometriosis treatment. A protein-protein interaction (PPI) was established using overlapping genes. Analyses of enrichment of function and signaling pathways were undertaken using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes databases to select "hub genes." Finally, the feasibility of analysis based on network pharmacology was determined using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. We demonstrated that PRA has 25 bioactive components and 167 putative targets that are therapeutically important. The anti-inflammatory and immune-boosting actions of tumor necrosis factor, albumin, signal transducer and activator of transcription (STAT)3, mitogen-activated protein kinase, Jun, interleukin (IL)-1B, prostaglandin-endoperoxide synthase 2, matrix metalloproteinase-9, vascular endothelial growth factor A, and IL-6 were identified as prospective targets. Seven major compounds in PRA and related to the STAT3 pathway could bind spontaneously to it. RT-qPCR and western blotting showed that expression of STAT3 and phospho-STAT3 was reduced significantly after PRA intervention. Hence, analyses of the active components of traditional Chinese medicine formulations through network pharmacology may open up new ideas for the treatment of diseases.

The role of endoplasmic reticulum stress in endometriosis

Endometriosis is a chronic gynecologic disorder characterized by abnormal growth of endometrium-like tissues in the ectopic regions of the pelvic peritoneum. The pathophysiology of endometriosis is not completely understood; however, excessive endometrial cell proliferation together with resistance to apoptosis facilitates the migration, implantation, and survival of endometrial cells in the distant sites. Endoplasmic reticulum (ER) stress response (also called unfolded protein response) is a cellular defense mechanism triggered by ER stress. When severe enough, the so-called response initiates cell suicide, i.e., apoptosis. Therefore, therapeutic induction of ER stress in endometriotic cells could promote apoptosis and contribute to the management of disease. In this review, we discuss the pathogenic role of ER stress in endometriosis and the most recent findings regarding the induction of ER stress in connection with endometriosis.

History of Endometriosis Is Independently Associated with an Increased Risk of Ovarian Cancer

Background: Endometriosis is a complex gynecologic disorder that has been associated with a higher risk of ovarian cancer. The purpose of this work is to determine to what extent a history of endometriosis is a risk factor for ovarian cancer in a Spanish population. Methods: A retrospective case–control study was conducted using de-identified data from the Spanish National Health System’s “Primary Care Clinical Database” and “Hospital Minimum Basic Data Set” for the period 2013–2017. Multiple logistics regression analysis was conducted to determine associations between ovarian cancer and endometriosis controlled by sociodemographic characteristics and comorbidities. Results: Data from 608,980 women were analyzed, with 4505 presenting ovarian cancer. Endometriosis patients were shown to have a 2.66-fold increased risk of ovarian cancer when compared to those who did not have endometriosis by controlling age and other relevant comorbidities. Conclusions: This case–control study based on clinical administrative data has found that a history of endometriosis is independently associated with an increased risk of ovarian cancer. More research is needed to determine if a history of endometriosis affects survival results in ovarian cancer patients.

Risk Factors for Ovarian Cancer: An Umbrella Review of the Literature

Several non-genetic factors have been associated with ovarian cancer incidence or mortality. To evaluate the strength and validity of the evidence we conducted an umbrella review of the literature that included systematic reviews/meta-analyses that evaluated the link between non-genetic risk factors and ovarian cancer incidence and mortality. We searched PubMed, EMBASE, Cochrane Database of Systematic Reviews and performed a manual screening of references. Evidence was graded into strong, highly suggestive, suggestive or weak based on statistical significance of the random effects summary estimate and the largest study in a meta-analysis, the number of cases, between-study heterogeneity, 95% prediction intervals, small study effects, and presence of excess significance bias. We identified 212 meta-analyses, investigating 55 non-genetic risk factors for ovarian cancer. Risk factors were grouped in eight broad categories: anthropometric indices, dietary intake, physical activity, pre-existing medical conditions, past drug history, biochemical markers, past gynaecological history and smoking. Of the 174 meta-analyses of cohort studies assessing 44 factors, six associations were graded with strong evidence. Greater height (RR per 10 cm 1.16, 95% confidence interval (CI) 1.11-1.20), body mass index (BMI) (RR ≥ 30 kg/m2 versus normal 1.27, 95% CI 1.17-1.38) and three exposures of varying preparations and usage related to hormone replacement therapy (HRT) use increased the risk of developing ovarian cancer. Use of oral contraceptive pill reduced the risk (RR 0.74, 95% CI 0.69-0.80). Refining the significance of genuine risk factors for the development of ovarian cancer may potentially increase awareness in women at risk, aid prevention and early detection.

Malignant transformation of endometriosis in a laparoscopic trocar site a case report

BACKGROUND

Malignant transformation of endometriosis is infrequent at the laparoscopic trocar site. Although malignant transformation is uncommon, it must be acknowledged in order to achieve radical resection.

CASE PRESENTATION

We report on a 54-year-old woman with trocar site endometriosis 2 years after laparoscopic ovarian endometrial resection. Physical examination revealed a subcutaneous solid tumor with a diameter of 3 cm surrounding the scar of laparoscopic surgery in the right lower abdomen. Transabdominal ultrasonography showed a cystic tumor in the subcutaneous adipose layer of the right lower abdomen. The pathological diagnosis was poorly differentiated endometrioid carcinoma. Hysterectomy, bilateral salpingo-oophorectomy and pelvic lymphadenectomy were then performed. Histological examination revealed mixed endometrioid carcinoma and clear cell carcinoma. After six cycles of chemotherapy, computed tomography showed no signs of recurrence.

CONCLUSIONS

Malignant transformation of laparoscopic endometriosis is very uncommon, and the diagnosis and stage are determined by clinical manifestations and imaging examination. The main therapy methods are radical surgery combined with neoadjuvant chemotherapy and adjuvant radiotherapy. At the same time, reducing iatrogenic abdominal incision implantation is an effective prevention method.

Altered p16Ink4a, IL-1β, and Lamin b1 Protein Expression Suggest Cellular Senescence in Deep Endometriotic Lesions

Endometriosis causes immunological and cellular alterations. Endometriosis lesions have lower levels of lamin b1 than the endometrium. Moreover, high levels of pro-inflammatory markers are observed in the peritoneal fluid, follicular fluid, and serum in endometriosis lesions. Thus, we hypothesized that the accumulation of senescent cells in endometriosis tissues would facilitate endometriosis maintenance in an inflammatory microenvironment. To study senescent cell markers and the senescence-associated secretory phenotype (SASP) in endometriosis lesions, we conducted a cross-sectional study with 27 patients undergoing video laparoscopy for endometriosis resection and 19 patients without endometriosis. Endometriosis lesions were collected from patients with endometriosis, while eutopic endometrium was collected from patients both with and without endometriosis. Tissues were evaluated for senescence markers (p16Ink4a, lamin b1, and IL-1β) and interleukin concentrations. The expression of p16Ink4a increased in lesions compared to that in eutopic endometrium from endometriosis patients in the secretory phase. In the proliferative phase, lesions exhibited lower lamin b1 expression but higher IL-4 expression than the eutopic endometrium. Further, IL-1β levels were higher in the lesions than in the eutopic endometrium in both the secretory and proliferative phases. We believe that our findings may provide targets for better therapeutic interventions to alleviate the symptoms of endometriosis.

Comparison of methods for isolation and quantification of circulating cell-free DNA from patients with endometriosis

RESEARCH QUESTION

Which is the optimal extraction method for isolating and quantifying circulating cell-free DNA (ccfDNA) from patients with endometriosis? Endometriosis is a common benign disease, associated with pain, infertility and reduced quality of life. Endometriosis is also a known risk factor for various cancers. Robust biomarkers for early detection and prediction of prognosis, however, are lacking. CcfDNA is an easy to obtain biomarker associated with prognosis of cancer patients and enables non-invasive analysis of somatic mutations. Recently, elevated levels of ccfDNA were detected in patients with endometriosis.

DESIGN

Two different ccfDNA extraction methods were compared: Maxwell RSC ccfDNA plasma kit (Maxwell) and QiAamp minElute ccfDNA mini kit (QIAamp). The ccfDNA and circulating mitochondrial DNA (mtDNA) quantities from 34 patients diagnosed with endometriosis were analysed. Fluorometric measurement and quantitative reverse transcription polymerase chain reaction (qRT-PCR) of short and long ALU and mtDNA fragments were used to quantiy ccfDNA.

RESULTS

The yield of ccfDNA isolated with the Maxwell method was significantly higher compared with the QIAamp method (P < 0.0001). Integrity of ccfDNA was significantly higher in the QIAamp isolate (P < 0.0001). Recovered mtDNA was not significantly different between both extraction methods used.

CONCLUSIONS

The choice of extraction method can significantly influence the ccfDNA output and integrity. Both methods, however, enabled isolation of sufficient ccfDNA for further downstream applications. With this approach, isolation of ccfDNA could enable the non-invasive detection and analysis of somatic mutation within endometriosis tissue.

Analysis of differences in the transcriptomic profiles of eutopic and ectopic endometriums in women with ovarian endometriosis

Background

Endometriosis is a common gynecological disease among women in their reproductive years. Although much effort has been made, the pathogenesis of this disease and the detailed differences between eutopic endometrial cells and ectopic endometrial cells are still unclear.

Methods

In this study, eutopic and ectopic endometrial cells were collected from patients with and without endometriosis and RNA sequencing was performed. The gene expression patterns and differentially expressed genes (DEGs) in eutopic and ectopic endometrial cells, as well as control endometrial cells, were analyzed using a weighted gene co-expression network analysis (WGCNA) and the DESeq2 package. The functions of significant genes were detected using Gene ontology (GO) enrichment analysis, and qRT-PCR validation was performed.

Results

The results indicated that eight gene modules were found among these three groups. They also indicated that the gene module, which is highly related to eutopic endometrial cells, was mainly enriched in cell adhesion, embryo implantation, etc., while the gene module related to ectopic endometrial cells was mainly enriched in cell migration, etc. The results of differential expression analysis were generally consistent with the WGCNA results through identified significant DEGs between different groups. These DEGs may play an important role in the occurrence of endometriosis, including the infertility associated gene ARNTL and PIWIL2, tissue remodeling gene MMP11, cell survival and migration gene FLT1, inflammatory response gene GNLY, the tumor suppressor genes PLCD1, etc. Further analysis suggested the function of adhesion is stronger in ectopic endometrial cells than in eutopic endometrial cells, while the ectopic endometrium may have a higher potential risk of malignant transformation than eutopic endometrium.

Conclusions

Overall, these data provide a reference for understanding the pathogenesis of endometriosis and its relationship with malignant transformation.

The role of mitogen-activated protein kinase signaling pathway in endometriosis

AIM

Endometriosis is an estrogen-dependent chronic inflammatory condition which causes pain, infertility, and predisposition for ovarian cancer. Endometriosis generates a unique microenvironment for survivability of endometriotic lesions which includes cell proliferation, differentiation, migration, and apoptosis. For these cellular activities, cascading activations of intracellular kinases are needed. Many kinase signaling pathways, IKKβ/NK-κB pathway, PI3K/AKT/mTOR, and the mitogen-activated protein kinase (MAPK) pathways (ERK1/2, p38, and JNK), are activated in endometriosis. In this review, we focus on the role of MAPK pathways in endometriosis.

METHODS

To identify the role of MAP Kinase signaling pathway in endometriosis we searched the Pubmed database using the search terms in various combinations "endometriosis," "endometrium," "ovary," "MAPK pathway," "ERK pathway," "p38 pathway," "JNK pathway," "estrogen," and "progesterone."

RESULTS

According to the current literature, MAPK signaling pathway has various roles in generating microenvironment and survival of endometriosis. Abnormal MAPK activation in migration, implantation, growth, invasion into the pelvic structures, proliferation, and apoptosis leads to the form of endometriosis and to worsen the condition in patients with endometriosis.

CONCLUSION

To further investigations on the effective and long-term endometriosis treatment, MAPK signaling pathways may be targeted. Molecular mechanism of MAPK signaling pathway in endometriosis should be more deeply understood and clinical trials should be more commonly performed for possible new endometriosis treatments to improve fertility and rescue endometriosis irreversibly.

Ovarian endometriosis, a precursor of ovarian cancer: Histological aspects, gene expression and microRNA alterations (Review)

Ovarian endometriosis is a frequent chronic gynecological disease with an uncertain evolution regarding its progression or association with ovarian malignant lesions. The present review summarized the histological aspects, gene expression and microRNA (miRNA/miR) alterations associated with ovarian endometriosis and cancer and their possible interaction. The endometriosis-ovarian cancer interaction has been proposed by certain researchers as a single entity. Histological results indicated that endometriosis has been in different circumstances coexisting with ovarian cancer, with reference to endometrioid and clear cell carcinoma. Endometriosis with moderate and severe atypia can influence cell proliferation and architecture, resulting in a possible malignant transformation. Gene expression analysis indicated that the pathologies of both endometriosis and ovarian cancer are characterized by genetic instability from a molecular point of view, as several important genetic mutations, including ARID1A, PI3KCA, PTEN, BRCA1, BRCA2, TP53 and KRAS genes, were identified. miRNA alterations have been implicated in the regulation of gene expression. Common dysregulated miRNAs, such as miR-331, miR-335, miR-891, miR-548, miR-124, miR-148, miR-215, miR-192, miR-337, miR-153, miR-155, miR-144, miR-221 and miR-3688 were extensively investigated in understanding endometriosis and ovarian cancer evolution. From a combined viewpoint including histological aspects, gene expression and miRNA alterations, it is reasonable to speculate that endometriosis is associated with ovarian cancer. Ovarian endometriosis lesions may present a risk for ovarian malignant lesions, which supports a model of endometriosis as a malignant precursor. However, the endometriosis-ovarian cancer association is not widely accepted in the literature and additional studies are required to validate this association.

Hemoglobin-induced continuous activation of macrophages in endometriotic cysts: a potential mechanism of endometriosis development and carcinogenesis

Endometriosis is a chronic inflammatory disease. Endometriotic cysts contain hemoglobin (Hb) and infiltrated macrophages, indicating that the metabolism of Hb by macrophages may play an important role in the inflammation of endometriotic cysts. In this study, we investigated the distribution of immune cells and CD163 (Hb receptor)-positive cells in the endometriotic cyst wall using immunohistochemistry. We also examined the role of macrophage activation by Hb on the pathogenesis of endometriotic cysts by measuring the cytokine concentration in the cystic fluids and macrophage-culture supernatant using ELISA. Macrophages were the most prominent immune cells observed in the endometriotic cysts and were differentially distributed in the different histological areas of the cyst wall. The localization of CD163-positive macrophages was restricted to the hemorrhagic and outer areas in the cyst wall. High concentrations of IL-6 and CCL2 were found in the cystic fluids, and inflammatory cytokines (IL-6, TNF-α, and CCL2) were secreted from macrophages on stimulation by Hb. IL-6 is a promotional factor for endometriotic stromal cells and ovarian clear cell carcinoma, the most common histological subtype of endometriosis-related ovarian cancer, hence, the continuous activation of macrophages by Hb could be a potential mechanism underlying endometriosis development and carcinogenesis.

The Many Faces of Endometriosis-Related Neoplasms in the Same Patient: A Brief Report

INTRODUCTION

Endometriosis is a common benign gynecological condition that can be associated with a slightly increased risk of developing a wide range of malignancies.

CASE PRESENTATION

We herein report a singular case of a 62-year-old woman with a history of pelvic endometriosis, referred to our institution for chronic pelvic pain and uterine bleeding, with clinical and radiological evidence of left ovarian mass of 18 cm in largest diameter and multiple nodular mural lesions of the uterine cavity. The patient underwent exploratory laparotomy followed by hysterectomy, bilateral salpingo-oophorectomy, and omentectomy with pelvic lymph-node sampling. The histological examination of the ovarian mass revealed a clear-cell ovarian carcinoma arising from an endometriotic cyst. The microscopic examination of the uterine cavity showed multiple conventional leiomyomas, diffuse foci of adenomyosis, and a 1.5-cm yellow nodule diagnosed as low-grade endometrial stromal sarcoma associated with glandular atypical differentiation and with extension into parametrial and omental tissues. Following the diagnosis, the patient was treated with chemotherapy, radiation therapy, and hormonal therapy and after 9 months of follow-up is alive without local recurrences and distant metastases.

DISCUSSION/CONCLUSIONS

To the best of our knowledge, the present case represents the first evidence of the simultaneous occurrence of clear-cell carcinoma and low-grade endometrial stromal sarcoma arising within ovarian and uterine endometriotic foci, respectively.

Identification of a FAS/FASL haplotype associated with endometriosis in Iranian patients

Risk factors for ovarian cancer include a number of genetic variants as well as endometriosis. The FAS-FASL system is one of the apoptotic pathways that play an essential role in the apoptotic process within the endometrium. Here, we evaluate the correlation between FAS-FASL polymorphisms with the risk of endometriosis in Iranian patients and healthy controls. We extracted DNA from whole blood samples using a DNA Purification Kit. Using the PCR-RFLP method, three SNPs, including FAS (-670 A/G) and FASL (-844 C/T and _124G/A) genes, were genotyped in 112 patients with endometriosis as well as 110 healthy controls. The frequency of genotypes and the alleles of these SNPs were analyzed by the chi-squared test for the significant association. Haplotype analysis was done by the PLINK software. The frequency distribution of haplotypes was significant between SNPs so that the ACG haplotype was more frequent in the cases than in the controls (p = .017). These results indicate that haplotype analysis can be useful for SNP analysis. The ACG haplotypes in FAS-670A/G, FASL-844C/T, and _124G/A genes may be correlated with the progression of endometriosis.

Association between endometriosis and gynecological cancers: a critical review of the literature

BACKGROUND

Endometriosis is one of the most common benign gynecological diseases with an occurrence approximately 10% in reproductive age. Endometriosis has been proposed as a possible precursor of certain ovarian carcinomas such as clear cell and endometrioid ovarian carcinomas. In addition to this pathogenic link, the association with other gynecological tumors and breast cancer has been studied on an epidemiological basis in several studies.

OBJECTIVE

The aim of this review was to critically present the recent published evidence on the association of endometriosis with gynecological cancer, and with a special emphasis on ovarian cancer.

MATERIALS AND METHODS

A search for eligible studies was conducted in three electronic databases, MEDLINE, EMBASE and CINAHL, for original research in humans published in any language.

RESULTS

The present review includes studies examining the association between endometriosis and different types of gynecological cancer (i.e., 25 studies on ovarian cancer, 8 studies on breast cancer, 8 studies on endometrial cancer and 2 studies on cervical cancer).

CONCLUSION

The present literature supports the pre-existing evidence suggesting an association between ovarian cancer and endometriosis and specifically its two histologic subtypes (endometrioid and ovarian clear cell cancer). The most recent population-based epidemiological studies cannot provide a clear association between endometriosis and endometrial, cervical or breast cancer.

Endometriosis: Three-year histopathological perspective from the largest hospital in Africa

BACKGROUND

Endometriosis refers to the presence of ectopic endometrial tissue outside the uterus, that may result in infertility or recurrent implantation failure.

AIMS

We aimed to document the number of histopathologically confirmed cases of endometriosis at the largest hospital in Africa during a three-year timeframe. Age, topographic site, pathological components, CD10 immunohistochemistry, metaplasia and associated neoplasms were documented.

METHOD

A retrospective, descriptive cross-sectional review of confirmed cases of endometriosis was conducted.

RESULTS

Thirty-four (n = 34) patients were confirmed to have endometriosis within 43 topographic sites. More than one topographic site of involvement was documented in 5 patients. The age range was 24 to 58 years [median age 36.4 ± 8.03; mean 34.5 ± 8.03 yrs]. The most frequent diagnostic combination was the triad of endometrial glands, stroma and chronic haemorrhage as confirmed in 53% of the cases. The most frequent topographic site of involvement was the ovary (27.9%) followed by the fallopian tubes (16.7%), umbilical region (13.9%), and abdominal wall (11.6%). Endometriotic cyst was reported in 10 cases (29.4%) and the ovary was the most common site in which endometriotic cysts occurred (p < .01). Endometrioma was only confirmed at the abdominal wall of one patient. CD10 immunochemistry was requested in 5 cases and confirmed the presence of endometrial stroma in all cases tested. Ciliated metaplasia was common (62%). Endometriosis was documented incidentally in context of two cases of neoplasia (pre-invasive and invasive).

CONCLUSION

Endometriosis is diagnosed predominantly, but not exclusively, in women of child-bearing age. Ovarian involvement has a propensity to develop endometriotic cysts. CD10 immunohistochemistry has diagnostic value when endometrial stroma is limited or inconspicuous.

Epithelial ovarian cancer risk: A review of the current genetic landscape

Ovarian cancer is the fourth most common cause of cancer-related death in women in the developed world, and one of the most heritable cancers. One of the most significant risk factors for epithelial ovarian cancer (EOC) is a family history of breast and/or ovarian cancer. Combined risk factors can be used in models to stratify risk of EOC, and aid in decisions regarding risk-reduction strategies. Germline pathogenic variants in EOC susceptibility genes including those involved in homologous recombination and mismatch repair pathways are present in approximately 22% to 25% of EOC. These genes are associated with an estimated lifetime risk of EOC of 13% to 60% for BRCA1 variants and 10% to 25% for BRCA2 variants, with lower risks associated with remaining genes. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) thought to explain an additional 6.4% of the familial risk of ovarian cancer, with 34 susceptibility loci identified to date. However, an unknown proportion of the genetic component of EOC risk remains unexplained. This review comprises an overview of individual genes and SNPs suspected to contribute to risk of EOC, and discusses use of a polygenic risk score to predict individual cancer risk more accurately.

Ovarian cancer in the world: epidemiology and risk factors

Aim: Ovarian cancer is one of the most common gynecologic cancers that has the highest mortality rate. Considering the fact that knowledge on the incidence, mortality of ovarian cancer, as well as its risk factors is necessary for planning and preventing complications, this study was conducted with the aim of examining the epidemiology and risk factors of ovarian cancer in the world.

Materials and methods: In order to access the articles, Medline, Web of Science Core Collection, and Scopus databases were searched from their start to the year 2018. Full-text, English observational studies that referred to various aspects of ovarian cancer were included in the study.

Results: In total, 125 articles that had been published during the years 1925–2018 were entered into the study. Ovarian cancer is the seventh most common cancer among women. Increased risk factors of cancer have led to an upward trend in the incidence of cancer around the world. In 2018, 4.4% of entire cancer-related mortality among women was attributed to ovarian cancer. Although the incidence of cancer is higher among high Human Development Index (HDI) countries, the trend of mortality rate tends to be reversing. Various factors affect the occurrence of ovarian cancer, from which genetic factor are among the most important ones. Pregnancy, lactation, and oral contraceptive pills play a role in reducing the risk of this disease.

Conclusion: This study provides significant evidence about ovarian cancer. Considering the heavy burden of ovarian cancer on women's health, preventive measures as well as health education and early detection in high risk groups of women are highly recommended. Although some risk factors cannot be changed, a focus on preventable risk factors may reduce the risk of ovarian cancer. More studies are needed to explore the role of unclear risk factors in ovarian cancer occurrence.

Endometriosis-associated ovarian cancer is a single entity with distinct clinicopathological characteristics

Objective: To compare the clinicopathological features and chemotherapy response of ovarian clear cell carcinoma (CCC) and endometrioid carcinoma (EC) associated with endometriosis or not. Methods: This was a retrospective study of 128 patients diagnosed with CCC and EC from 2002 to 2017. Clinicopathological features and chemotherapy response were analyzed. Results:There were 34 women with endometriosis-associated ovarian cancer (EAOC) and 94 with non-endometriosis associated ovarian cancer (non-EAOC) according to Sampson's and Scott's criteria. The mean diagnosis age in the EAOC group was 48.65 vs. 54.39 years in non-EAOC (p = 0.002). Compared with non-EAOC, the EAOC patients were more likely to have an earlier menarche age (13 vs. 14 years, p = 0.001), a higher incidence of infertility (26.47% vs. 10.64%, p = 0.026), and an earlier stage tumor (91.18% vs. 73.40% in stages I-II, p = 0.032). At a median follow-up time of 32.9 months, overall survival among patients with EAOC was significantly longer (109.8 vs. 47.4 months, p = 0.007). Association with endometriosis (p = 0.033) was the significant favorable prognostic factors associated with survival. However, stratifying by stage, the overall survival advantage of EAOC was not significant. Although EAOC had a better prognosis, no difference was observed in chemotherapy response between the two groups (p = 0.535). Conclusions: The EAOC patients were often diagnosed at a younger age, an earlier stage, and related to nulliparity and infertility. Patients with EAOC had a better prognosis than non-EAOC, early stage rather than association with endometriosis may be the driver of survival.

Epigenetic role of the nuclear factor NF-Y on ID gene family in endometrial tissues of women with endometriosis: a case control study

BACKGROUND

A predominant difference between endometrial and normal cells is higher proliferation rate in the former cells which is benign. The genes of inhibitor of differentiation (ID) family play a major role in cell proliferation regulation which might be targeted by the nuclear transcription factor Y (NF-Y) for subsequent epigenetic modifications through the CCAAT box regulatory region. The present study was designed to investigate the epigenetic role of NF-Y on ID gene family in endometrial tissue of patients with endometriosis.

MATERIALS & METHODS

In this case-control study, 20 patients with endometriosis and 20 normal women were examined for the relative expression of the NF-YA, NF-YB, NF-YC and ID genes by real-time PCR during the proliferative phase. The occupancy of NF-Y on CCAAT box region of ID genes was investigated using chromatin immunoprecipitation (ChIP) followed by real-time PCR.

RESULTS

The NF-YA was over-expressed in eutopic endometrium during the proliferative phase. Although the expression level of NF-YB and NF-YC were unchanged in eutopic samples, they were remarkably higher in ectopic group (P<0.05). The ID2 and ID3 genes were up-regulated in ectopic and eutopic tissues, however ID1 and ID4 genes were down-regulated in these samples (P<0.05). The ChIP analysis revealed significant enrichment of NF-Y on regulatory regions of ID2,3 genes in eutopic group, but reduced binding level of NF-Y to the ID1,3 promoters in ectopic specimens (P<0.05).

CONCLUSION

The ability of NF-Y to regulate ID genes via CCAAT box region suggests the possible role of NF-Y transcription factor in epigenetic changes in endometrial tissues which may open novel avenues in finding new therapeutic strategies.

Endometriosis-associated ovarian cancer: What have we learned so far?

Endometriosis is defined as the presence of ectopic endometrial tissue outside of the uterine cavity, most commonly in the ovaries and peritoneum. It is a complex disease that is influenced by multiple factors. It is also a common gynecological disorder and affects approximately 10-15% of all women of reproductive age. Recent molecular and pathological studies indicate that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), particularly endometrioid and clear cell ovarian cancers. Although histological and epidemiological studies have demonstrated that endometriosis has a malignant potential, the molecular mechanism that underlies the malignant transformation of endometriosis is still controversial, and the precise mechanism of carcinogenesis must be fully elucidated. Currently, the development and improvement of a new sequencing technology, next-generation sequencing (NGS), has been increasingly relevant in cancer genomics research. Recently, NGS has also been utilized in clinical oncology to advance the personalized treatment of cancer. In addition, the sensitivity, speed, and cost make NGS a highly attractive platform compared to other sequencing modalities. For this reason, NGS may lead to the identification of driver mutations and underlying pathways associated with EAOC. Here, we present an overview of the molecular pathways that have led to the current opinions on the relationship between endometriosis and ovarian cancer.

PTGER3 induces ovary tumorigenesis and confers resistance to cisplatin therapy through up-regulation Ras-MAPK/Erk-ETS1-ELK1/CFTR1 axis

Background

Inflammatory mediator prostaglandin E2–prostaglandin E2 receptor EP3 (PTGER3) signaling is critical for tumor-associated angiogenesis, tumor growth, and chemoresistance. However, the mechanism underlying these effects in ovarian cancer is not known.

Methods

An association between higher tumoral expression of PTGER3 and shorter patient survival in the ovarian cancer dataset of The Cancer Genome Atlas prompted investigation of the antitumor effects of PTGER3 downmodulation. PTGER3 mRNA and protein levels were higher in cisplatin-resistant ovarian cancer cells than in their cisplatin-sensitive counterparts.

Findings

Silencing of PTGER3 via siRNA in cancer cells was associated with decreased cell growth and less invasiveness, as well as cell-cycle arrest and increased apoptosis, mediated through the Ras-MAPK/Erk-ETS1-ELK1/CFTR1 axis. Furthermore, sustained PTGER3 silencing with multistage vector and liposomal 2’-F-phosphorodithioate-siRNA–mediated silencing of PTGER3 combined with cisplatin resulted in robust antitumor effects in cisplatin-resistant ovarian cancer models.

Interpretation

These findings identify PTGER3 as a potential therapeutic target in chemoresistant ovarian cancers expressing high levels of this oncogenic protein.

Fund

National Institutes of Health/National Cancer Institute, USA.

The risk of extra-ovarian malignancies among women with endometriosis: A systematic literature review and meta-analysis

We conducted a meta-analysis of studies reporting on the risk of extra-ovarian malignancies among women with endometriosis. Summary relative risk (SRR) and 95% confidence intervals (CI) were calculated through random effect models. We explored causes of between-studies heterogeneity and assessed the presence of publication bias. We included 32 studies published between 1989 and 2018. We found an increased risk of endometrial (SRR 1.38, 95%CI 1.10-1.74) and thyroid cancer (SRR 1.38, 95%CI 1.17-1.63), and inverse association with cervical cancer (SRR 0.78, 95%CI 0.60-0.95). No association emerged for breast cancer (SRR 1.04, 95%CI 0.99-1.09) and melanoma (SRR 1.31, 95%CI 0.86-1.96). Between-study heterogeneity was large for breast and endometrial cancer and melanoma. Associations were generally stronger in case-control, cross-sectional, and cohort studies with internal control group, compared to cohort studies with external control group. No indication for publication bias was found. Our conclusions need to be confirmed in properly designed cohort studies with clinical confirmation of endometriosis.

Unfolded protein response, a link between endometrioid ovarian carcinoma and endometriosis: A pilot study

The aim of the present study was to analyze the expression profile of unfolded protein response (UPR) genes in endometrioid ovarian carcinoma and to evaluate its possible involvement in the neoplastic progression of endometriosis. An experimental retrospective pilot study was conducted on women with a diagnosis of endometrioid ovarian carcinoma at FIGO stage IA, ovarian endometriotic cysts or healthy subjects without a previous diagnosis of endometriosis. The expression profiles of UPR genes (ATF6, GRP78, CHOP and XBP1) were compared among ovaries with endometrioid ovarian cancer, endometriotic ovarian cysts, healthy contralateral ovaries and eutopic and healthy endometrial tissues. A significantly higher expression of ATF6 and GRP78 was detected in the affected ovaries in comparison with the healthy contralateral ovaries, while CHOP and XBP1 exhibited a significantly lower expression. XBP1 was overexpressed in endometrial tissues and its expression gradually decreased in endometriosis cysts and endometrioid ovarian carcinoma. These results support the hypothesis that alterations in the UPR genes CHOP and XBP1 are involved in the neoplastic progression of endometrioid ovarian cancer and are acquired following ovarian localization of ectopic endometrial cells.

Effect of neuromuscular electrical stimulation for endometriosis-associated pain: A retrospective study

This retrospective study evaluated the effect of neuromuscular electrical stimulation (NMES) for the treatment of endometriosis-associated pain (EAP).A total of 154 patients with EAP were included and were divided into 2 groups in this retrospective study. Eighty-three patients were assigned a treatment group, and underwent NMES therapy, while 71 subjects in the control group were at waiting list. The primary outcome of pain was measured by the numerical rating scale (NRS) and the Endometriosis Symptom Severity scale (ESSS). The secondary outcome was quality of life, measured by the 36-Item Short Form Health Survey (SF-36). All outcomes were measured before and after 5-week and 10-week treatment. Moreover, we also recorded the adverse events in this study.After 5-week treatment, no significant differences in all outcome measurements were found between the 2 groups. However, after 10-week treatment, NMES therapy exerted better outcomes in NRS (P = .02), ESSS (P = .04), and SF-36 [Physical Component Summary (PCS), P < .01; Mental Component Summary (MCS), P < .01], compared with the patients at the waiting list. Moreover, no significant differences of all adverse events were found between the 2 groups, although mild and acceptable adverse events occurred in the treatment group.This study demonstrated that NMES is effective for treating patients with EAP.

Depleted lamin B1: a possible marker of the involvement of senescence in endometriosis?

PROPOSE

Endometriosis is a benign disease characterized by implantation and the growth of endometrial tissue outside the uterine cavity and it shares similarities with cancer. Lamin B1, p16 and p21 play a role on cell cycle regulation, development, cell repair and its activities are related to cancers. Considering the similarities between endometriosis and cancer, the aim of the present cross-sectional study is to detect p16, p21 and Lamin B1 in the ectopic endometrium of patients with endometriosis (n = 8) with eutopic (n = 8) and control endometrium (n = 8) and relate them to the maintenance and development of endometriosis.

METHODS

Biopsies were obtained from both eutopic and ectopic, from deep infiltrating lesions, endometrium frozen and used for immunofluorescent (p16) or immunohistochemistry procedures (p16, p21, lamin B1).

RESULTS

Detected higher lamin B1 in the eutopic endometrium when compared with ectopic endometrium, with no differences between endometriosis tissue with control endometrium. Similar presence of p16 in all groups of patients and no p21 detection was observed.

CONCLUSION

We observed reduced detection of lamin B1 in the ectopic endometrium raising the possibility that the presence of senescent cells might be contributing to the maintenance and progression of endometriosis by apoptosis resistance and peritoneal stress inherent of the disease.

LINE-1 retrotransposon-mediated DNA transductions in endometriosis associated ovarian cancers

OBJECTIVE

Endometrioid (ENOC) and clear cell ovarian carcinoma (CCOC) share a common precursor lesion, endometriosis, hence the designation endometriosis associated ovarian cancers (EAOC). Long interspersed nuclear element 1 (LINE-1 or L1), is a family of mobile genetic elements activated in many cancers capable of moving neighboring DNA through 3' transductions. Here we investigated the involvement of specific L1-mediated transductions in EAOCs.

METHODS

Through whole genome sequencing, we identified active L1-mediated transductions originating within the TTC28 gene in 34% (10/29) of ENOC and 31% (11/35) of CCOC cases. We used PCR and capillary sequencing to assess the presence of specific TTC28-L1 transductions in formalin-fixed paraffin-embedded (FFPE) blocks from six different anatomical sites (five tumors and one normal control) for four ENOC and three CCOC cases, and compared the results to the presence of single nucleotide variations (SNVs)/frame shift (fs) mutations detected using multiplex PCR and next generation sequencing.

RESULTS

TTC28-L1 mediated transductions were identified in at least three tumor samplings in all cases, and were present in all five tumor samplings in 5/7 (71%) cases. In these cases, KRAS, PIK3CA, CTNNB1, ARID1A, and PTEN mutations were found across all tumor sites while other selected SNV/fs mutations of unknown significance were present at varying allelic frequencies.

CONCLUSION

The TTC28-L1 transductions along with classical driver mutations were near ubiquitous across the tumors, suggesting that L1 activation likely occurred early in the development of EAOCs. TTC28-L1 transductions could potentially be used to determine clonal relationships and to track ovarian cancer progression.

miRNA expression profiling in formalin-fixed paraffin-embedded endometriosis and ovarian cancer samples

Endometriosis is an inflammatory pathology associated with a negative effect on life quality. Recently, this pathology was connected to ovarian cancer, in particular with endometrioid ovarian cancer. microRNAs (miRNAs) are a class of RNA transcripts ~19–22 nucleotides in length, the altered miRNA pattern being connected to pathological status. miRNAs are highly stable transcripts, and these can be assessed from formalin-fixed paraffin-embedded (FFPE) samples leading to the identification of miRNAs that could be developed as diagnostic and prognostic biomarkers, in particular those involved in malignant transformation. The aim of our study was to evaluate miRNA expression pattern in FFPE samples from endometriosis and ovarian cancer patients using PCR-array technology and also to compare the differential expression pattern in ovarian cancer versus endometriosis. For the PCR-array study, we have used nine macrodissected FFPE samples from endometriosis tissue, eight samples of ovarian cancers and five normal ovarian tissues. Quantitative real-time PCR (qRT-PCR) was used for data validation in a new patient cohort of 17 normal samples, 33 endometriosis samples and 28 ovarian cancer macrodissected FFPE samples. Considering 1.5-fold expression difference as a cut-off level and a P-value <0.05, we have identified four miRNAs being overexpressed in endometrial tissue, while in ovarian cancer 15 were differentially expressed (nine overexpressed and six downregulated). The expression level was confirmed by qRT-PCR for miR-93, miR-141, miR-155, miR-429, miR-200c, miR-205 and miR-492. Using the interpretative program Ingenuity Pathway Analysis revealed several deregulated pathways due to abnormal miRNA expression in endometriosis and ovarian cancer, which in turn is responsible for pathogenesis; this differential expression of miRNAs can be exploited as a therapeutic target. A higher number of altered miRNAs were detected in endometriosis versus ovarian cancer tissue, most of them being linked with epithelial-to-mesenchymal transition.

Endometriotic cyst fluid induces reactive oxygen species (ROS) in human immortalized epithelial cells derived from ovarian endometrioma

OBJECTIVES

Endometriotic cyst fluid (ECF) contains a large amount of reactive oxygen species (ROS), and endometriotic cysts are exposed to strong oxidative stress, which may cause malignant transformation. In this study, ROS production by ECF was clinically analysed.

METHODS

Human immortalized epithelial cells derived from ovarian endometrioma (EMosis-CC/TERT 1) were treated with ECF. In addition, ROS production in EMosis-CC/TERT 1 was measured, and its clinical significance was analysed.

RESULTS

A total of 38 ECF samples were obtained from patients diagnosed with endometriotic cysts. In EMosis-CC/TERT1, significantly higher levels of ROS were induced by ECF than by the vehicle control and ferric nitrilotriacetate. There were no significant differences in ROS production by laterality and preoperative serum CA125 values. There were several patients whose cyst sizes were approximately 5 cm and had relatively high ROS production. Production of ROS by ECF was relatively higher in patients older than 40 years of age than in those younger than 40.

DISCUSSION

Our study revealed that ROS are highly produced by ECF in EMosis-CC/TERT1 cells; therefore, exposure to ECF induced strong oxidative stress. Development of a therapeutic strategy to reduce ROS production might be useful for preventing malignant transformation of endometriotic cysts.

Endometriosis and risks for ovarian, endometrial and breast cancers: A nationwide cohort study

OBJECTIVE

A growing body of evidence suggests that endometriosis increases the risk for ovarian cancer, but it is less well studied whether the excess risk is confined to certain histotypes. Furthermore, it is not fully resolved if endometriosis is associated with endometrial- and breast cancer. The aim was to study overall- and histotype-specific risks for these hormone-dependent cancers in women with endometriosis.

METHODS

In the Danish National Patient Register, we identified 45,790 women with a clinical diagnosis of endometriosis during 1977-2012. We linked the cohort to the Danish Cancer Register and calculated standardized incidence ratios (SIRs) with corresponding 95% confidence intervals (CIs).

RESULTS

Endometriosis was associated with increased risks for ovarian cancer (SIR 1.34; 95% CI: 1.16-1.55), due primarily to endometrioid (SIR 1.64; 95% CI: 1.09-2.37) and clear-cell types (SIR 3.64; 95% CI: 2.36-5.38). An excess risk was also observed for endometrial cancer (SIR 1.43; 95% CI: 1.13-1.79), primarily of type 1 (SIR 1.54; 95% CI: 1.20-1.96); and the risk for breast cancer was increased among women aged ≥50years at first diagnosis of endometriosis (SIR 1.27; 95% CI: 1.12-1.42).

CONCLUSIONS

The results corroborate previous findings of increased risks for endometrioid and clear-cell ovarian cancer in women with endometriosis. As the first cohort study to date, we observed a significantly increased risk for endometrial cancer in women with a diagnosis of endometriosis. The increased breast cancer risk among women with endometriosis diagnosed at ≥50years of age should be studied further.

Molecular signatures of ovarian diseases: Insights from network medicine perspective

Dysfunctions and disorders in the ovary lead to a host of diseases including ovarian cancer, ovarian endometriosis, and polycystic ovarian syndrome (PCOS). Understanding the molecular mechanisms behind ovarian diseases is a great challenge. In the present study, we performed a meta-analysis of transcriptome data for ovarian cancer, ovarian endometriosis, and PCOS, and integrated the information gained from statistical analysis with genome-scale biological networks (protein-protein interaction, transcriptional regulatory, and metabolic). Comparative and integrative analyses yielded reporter biomolecules (genes, proteins, metabolites, transcription factors, and micro-RNAs), and unique or common signatures at protein, metabolism, and transcription regulation levels, which might be beneficial to uncovering the underlying biological mechanisms behind the diseases. These signatures were mostly associated with formation or initiation of cancer development, and pointed out the potential tendency of PCOS and endometriosis to tumorigenesis. Molecules and pathways related to MAPK signaling, cell cycle, and apoptosis were the mutual determinants in the pathogenesis of all three diseases. To our knowledge, this is the first report that screens these diseases from a network medicine perspective. This study provides signatures which could be considered as potential therapeutic targets and/or as medical prognostic biomarkers in further experimental and clinical studies. Abbreviations DAVID: Database for Annotation, Visualization and Integrated Discovery; DEGs: differentially expressed genes; GEO: Gene Expression Omnibus; KEGG: Kyoto Encyclopedia of Genes and Genomes; LIMMA: Linear Models for Microarray Data; MBRole: Metabolite Biological Role; miRNA: micro-RNA; PCOS: polycystic ovarian syndrome; PPI: protein-protein interaction; RMA: Robust Multi-Array Average; TF: transcription factor.