Potential scenarios leading to ovarian cancer arising from endometriosis

Factors in malignant transformation of ovarian endometriosis: A narrative review

Endometriosis is a common estrogen-dependent inflammatory disease with a chronic course and a tendency to recur. The association between endometriosis and cancer has been studied for several years. Numerous reports have demonstrated a strong association between specific ovarian malignancies and endometriotic lesions. Atypical endometriosis has been widely described as a malignant precursor to ovarian epithelial tumors, particularly clear cell carcinomas and endometrioid carcinomas. These histological types associated with endometriosis develop predominantly in the ovary rather than in extragonadal sites. The detailed molecular mechanism of etiology remains unclear. Recent studies have analyzed the genetic and molecular mechanisms involved in endometriosis-associated ovarian cancer. A critical role appears to be played by a carcinogenic model based on iron-induced oxidative stress, which is typical of the endometriosis microenvironment. It has been hypothesized that trans-tubal reflux of blood, endometrial cells and associated iron-induced oxidative stress underlie the development of endometriosis-associated ovarian cancer. However, the multifactorial mechanisms of this malignant transformation are not fully understood. The aim of this review is to summaries the current epidemiological, histopathological, genetic and molecular findings in the progression of endometriosis-associated ovarian cancer.

Madboli A, Hussien AG, Seif M. Exploring the protective effect of silver Croton tiglium nano-extract against azoxymethane induced toxicity in female reproductive organs in rats

Reproductive toxicity from food and environmental contaminants has greatly affected human life. Plants are a fundamental source of bioactive components for relieving the harmful effects of pollutants. Hydrazine metabolites pose health threats when they enter the food chain. Croton tiglium (C. tiglium) exhibits anti-inflammatory and anti-tumor properties. Silver nanoparticles enhance the chemical stability of C. tiglium. Reproductive toxicity of Azoxymethane (AOM) and anticancer effects of silver C. tiglium were evaluated. Thirty-six adult female rats were divided into six groups (n = 6) and treated with AOM with or without silver C. tiglium nano-extract as pre- and post-treatment. Sexual hormones and proteins were assessed under silver C. tiglium nano-extract and AOM. Histopathologically, AOM caused metaplastic myometrial endometriotic cysts and endometrial metaplasia. Silver C. tiglium in pre- and post-treated rats mitigated the carcinogenic effects of AOM. Immunohistochemically, AOM carcinogenicity was evident through moderate detection of the CK-7 tumor marker in the ovaries and uterus of the AOM-, simultaneous-, and post-treated groups. C. tiglium ameliorated this, with CK-7 slightly expressed in the pre-treated group. Furthermore, C. tiglium alleviated the negative impact on FSH, LH, and 17-β estradiol hormones. In conclusion, Silver C. tiglium nano-extract successfully prevented tumors in the ovaries and uterus of AOM-treated rats.

Causal effects of endometriosis on cancer risk: A Mendelian randomization study

Endometriosis has been reported in epidemiological studies to be associated with certain types of cancer. However, the presence of reverse causality and residual confounding due to common risk factors introduces uncertainty regarding the extent to which endometriosis itself contributes to the development of cancer. We performed the Mendelian randomization (MR) to investigate the causal associations between endometriosis and 34 different types of cancers. The results of the inverse-variance-weighted (IVW) model suggested that genetic predisposition to endometriosis was causally associated with an increased risk for ovarian cancer (OR = 3.2913; p-value = .0320). The genetic liabilities to endometriosis had causal associations with the decreased risk for skin cancer (OR = 0.9973; p-value = .0219), hematological cancer (OR = 0.9953; p-value = .0175) and ER- breast cancer (OR = 0.6960; p-value = .0381). The causal association of the above combinations were robust by test of heterogeneity and pleiotropy. Together, our study suggests that endometriosis had causal effect on cancer risk.

Heme metabolism and HO-1 in the pathogenesis and potential intervention of endometriosis

Endometriosis (EM) is one of the diseases related to retrograded menstruation and hemoglobin. Heme, released from hemoglobin, is degraded by heme oxygenase-1 (HO-1). In EM lesions, heme metabolites regulate processes such as inflammation, redox balance, autophagy, dysmenorrhea, malignancy, and invasion, where macrophages (Mø) play a fundamental role in their interactions. Regulation occurs at molecular, cellular, and pathological levels. Numerous studies suggest that heme is an indispensable component in EM and may contribute to its pathogenesis. The regulatory role of heme in EM encompasses cytokines, signaling pathways, and kinases that mediate cellular responses to external stimuli. HO-1, a catalytic enzyme in the catabolic phase of heme, mitigates heme's cytotoxicity in EM due to its antioxidant, anti-inflammatory, and anti-proliferative properties. Certain compounds may intervene in EM by targeting heme metabolism, guiding the development of appropriate treatments for all stages of endometriosis.

Research progress in endometriosis-associated ovarian cancer

Endometriosis-associated ovarian cancer (EAOC) is a unique subtype of ovarian malignant tumor originating from endometriosis (EMS) malignant transformation, which has gradually become one of the hot topics in clinical and basic research in recent years. According to clinicopathological and epidemiological findings, precancerous lesions of ovarian clear cell carcinoma (OCCC) and ovarian endometrioid carcinoma (OEC) are considered as EMS. Given the large number of patients with endometriosis and its long time window for malignant transformation, sufficient attention should be paid to EAOC. At present, the pathogenesis of EAOC has not been clarified, no reliable biomarkers have been found in the diagnosis, and there is still a lack of basis and targets for stratified management and precise treatment in the treatment. At the same time, due to the long medical history of patients, the fast growth rate of cancer cells, and the possibility of eliminating the earliest endometriosis-associated ovarian cancer, it is difficult to find the corresponding histological evidence. As a result, few patients are finally diagnosed with EAOC, which increases the difficulty of in-depth study of EAOC. This article reviews the epidemiology, pathogenesis, risk factors, clinical diagnosis, new treatment strategies and prognosis of endometriosis-associated ovarian cancer, and prospects the future direction of basic research and clinical transformation, in order to achieve stratified management and personalized treatment of ovarian cancer patients.

New insights about endometriosis-associated ovarian cancer: pathogenesis, risk factors, prediction and diagnosis and treatment

Previous studies have shown that the risk of malignant transformation of endometriosis in premenopausal women is approximately 1%, significantly impacting the overall well-being and quality of life of affected women. Presently, the diagnostic gold standard for endometriosis-associated ovarian cancer (EAOC) continues to be invasive laparoscopy followed by histological examination. However, the application of this technique is limited due to its high cost, highlighting the importance of identifying a non-invasive diagnostic approach. Therefore, there is a critical need to explore non-invasive diagnostic methods to improve diagnostic precision and optimize clinical outcomes for patients. This review presents a comprehensive survey of the current progress in comprehending the pathogenesis of malignant transformation in endometriosis. Furthermore, it examines the most recent research discoveries concerning the diagnosis of EAOC and emphasizes potential targets for therapeutic intervention. The ultimate objective is to improve prevention, early detection, precise diagnosis, and treatment approaches, thereby optimizing the clinical outcomes for patients.

Resveratrol protected against the development of endometriosis by promoting ferroptosis through miR-21-3p/p53/SLC7A11 signaling pathway

Resveratrol is involved in regulating ferroptosis, but its role in Endometriosis (EMS) is not clear. In this study, we aim to investigate the effect of ferroptosis and resveratrol intervention in the pathogenesis of EMS cyst. Cell proliferation, migration, and oxidative stress level were analyzed. The interaction of miR-21-3p and p53 was analyzed by dual luciferase assay. The interaction between p53 and SLC7A11 were analyzed by chromatin immunoprecipitation (CHIP). The miR-21-3p, GPX4, ACSL4, FTH1, p53, SLC7A11, Ptgs2 and Chac1 expression were analyzed by RT-qPCR or Western blot. The Fe3+ deposition and miR-21-3p, GPX4, FTH1 and SLC7A11 expressions were increased, and ACSL4, p53, Ptgs2 and Chac1 expression were decreased in EMS patients. Resveratrol inhibited migration, induced Ptgs2 and Chac1 expression in EESCs. Overexpression of miR-21-3p inhibited p53, Ptgs2 and Chac1 expression, and promoted SLC7A11 expression, which was reversed by resveratrol. miR-21-3p bound to p53, which interacted with SLC7A11. Resveratrol promoted Ptgs2 and Chac1 expression in the sh-p53 EESCs. Resveratrol reduced miR-21-3p and SLC7A11 expressions, and increased p53, Ptgs2 and Chac1 expressions, and Fe3+ deposition in the lesion tissues of EMS mice, which were reversed by miR-21-3p mimics. Resveratrol activated p53/SLC7A11 pathway by down-regulating miR-21-3p to promote ferroptosis and prevent the development of EMS.

TGF-β-regulated different iron metabolism processes in the development and cisplatin resistance of ovarian cancer

The impact of different iron metabolism processes (DIMP) on ovarian cancer remains unclear. In this study, we employed various gene chips and databases to investigate the role of DIMP in the initiation and development of ovarian cancer. cBioPortal was used to determine mutations in DIMP-associated genes in ovarian cancer. Kaplan-Meier plotter was used to examine the influence of DIMP on the prognosis of ovarian cancer. By analyzing 1669 serous ovarian cancer cases, we identified a range of mutations in iron metabolism genes, notably in those coding for the transferrin receptor (19%), melanotransferrin (19%), and ceruloplasmin (10%) in the iron import process, and glucose-6-phosphate isomerase (9%), hepcidin antimicrobial peptide (9%), metal regulatory transcription factor 1 (8%), and bone morphogenetic protein 6 (8%) in the iron regulation process. Compared to the unaltered group, the group with gene alterations exhibited a higher tumor mutation burden count (43 vs. 54) and more advanced histologic grade (78.19% vs. 87.90%). Compared to the normal ovarian counterparts, a reduction in expression was observed in 9 out of the 14 genes involved in iron utilization and 4 out of the 5 genes involved in iron export in ovarian cancer; in contrast, an increase in expression was observed in 2 out of the 3 genes involved in iron storage in ovarian cancer. Furthermore, in cisplatin-resistant cells compared to cisplatin-sensitive ones, the expression of all genes in iron storage and 13 out of 14 genes in iron import was decreased, while that of 8 out of the 10 genes in iron utilization was increased. In addition, survival curve analysis indicated that a higher expression in the majority of genes in the iron import process (12/21), or a reduced expression in most genes in the iron export process (4/5) correlated with poor progression-free survival. Additionally, TGF-β could regulate the expression of most iron metabolism-associated genes; particularly, expression of genes involved in the iron storage process (2/2) was inhibited after TGF-β1 or TGF-β2 treatment. In conclusion, DIMP plays multifaceted roles in the initiation, chemo-resistance, and prognosis of ovarian cancer. Therapeutically targeting DIMP may pave the way for more tailored treatment approaches for ovarian cancer.

Clinicopathological characteristics, molecular features and novel diagnostic strategies for the detection of malignant transformation of endometriosis (Review)

Endometriosis is a benign gynecological disease that affects women of reproductive age. Although malignant transformation of endometriosis is rare, physicians must be aware of this due to the high incidence of clear cell carcinoma of the ovary (CCC) in Japan. The most prevalent histological subtype of ovarian cancer is CCC (~70%) followed by endometrioid carcinoma (30%). The present review discusses the clinicopathological and molecular features of endometriosis-associated ovarian cancer (EAOC) as well as prospects for novel diagnostic strategies. Papers published between 2000 and 2022 in the PubMed and Google Scholar databases were included. Contents of the endometriotic cyst fluid may be involved in carcinogenesis, although the underlying mechanisms are largely unknown. Some studies have proposed a possible mechanism wherein excessive hemoglobin, heme and iron could cause an imbalance in intracellular redox homeostasis in endometriotic cells. Combined with DNA damage and mutations, the imbalances may induce the development of EAOC. Endometriotic cells evolve to adapt to the prolonged unfavorable oxidative microenvironmental stress. On the other hand, macrophages enhance the antioxidative defense mechanism and protect endometriotic cells against oxidative damage through intercellular crosstalk and signaling pathways. Therefore, changes in redox signaling, energy metabolism and the tumor immune microenvironment could be the key elements in the malignant transformation of certain endometriotic cell clones. Additionally, non-invasive bioimaging (i.e., magnetic resonance relaxometry) and biomarkers (i.e., tissue factor pathway inhibitor 2) may be promising tools for early-stage detection of the disease. In conclusion, the present review summarizes the latest advancements in research on the biological characteristics and early diagnosis of malignant transformation of endometriosis.

Heme induced progesterone-resistant profiling and promotion of endometriosis in vitro and in vivo

Endometriosis is an estrogen-dependent, progesterone-resistant gynecological disease with an unknown pathogenesis. Compared to women without endometriosis, women with endometriosis have a remarkably high heme level in the peritoneal fluid. To further investigate the pathomechanisms of heme in endometriosis, we aimed to identify the dysregulated expression of heme-trafficking proteins, such as PGRMC1/2 that are also receptors that mediate the non-genomic responses to progesterone, and heme-degrading enzymes between ectopic endometrial stromal cells and their normal counterparts. We found that heme could regulate progesterone receptor-related gene expression. Functional human endometrial stromal cell experiments showed that heme promotes cell proliferation and migration in a heme oxygenase-1-independent manner; moreover, blocking oxidative phosphorylation/ATP generation could abolish these effects of heme in vitro, whereas intraperitoneal hemopexin administration could alleviate heme-triggered ectopic lesions in vivo. Therefore, heme likely mediates the induction of progesterone resistance and simultaneously induces endometriosis via the mitochondrial oxidative phosphorylation pathway.

Identification of iron metabolism-related predictive markers of endometriosis and endometriosis-relevant ovarian cancer

Endometriosis is associated with ovarian cancers, mainly endometrioid and clear-cell carcinomas. Iron metabolism has been shown to play a role in endometriosis. Therefore, it is vital to explore the relationship between iron metabolism and ovarian cancer and to identify novel markers for diagnostics and therapeutics. The endometriosis dataset GSE51981 and the ovarian cancer dataset GSE26712 were obtained from the gene expression omnibus database, and differentially expressed genes were identified. Iron metabolism genes were obtained from molecular signatures database, and hub genes from the 3 datasets were obtained. Seven hub genes were identified by bioinformatic analysis, and 3 hub genes (NCOA4, ETFDH, and TYW1) were further selected by logistic regression, which were verified in an independent endometriosis dataset (GSE25628) and ovarian cancer dataset (GSE14407), showing good predictive diagnostic value (area under the receiver operating characteristic curve of 0.88 and 0.9, respectively). Gene Ontology, gene set enrichment analysis, and immune infiltration analysis further confirmed the related functions, pathways, and immune relationship between iron metabolism and ovarian cancer. This study highlights the potential of targeting iron metabolism in the prevention of potential ovarian cancer and in the further exploration of endometriosis and endometriosis-relevant ovarian cancer therapeutics.

The association between exposure to multiple toxic metals and the risk of endometriosis: Evidence from the results of blood and follicular fluid

BACKGROUND

Endometriosis affects up to 10 % of women of reproductive age and can lead to infertility. Research investigating whether combined exposure to arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) is related to an increased risk of endometriosis, especially using different biological samples to validate the association, is very limited.

OBJECTIVE

This investigation aimed to evaluate the associations between the concentrations of As, Cd, Pb and Hg in blood and follicular fluid and the risk of endometriosis.

METHODS

A total of 609 endometriosis cases and controls seen at the reproductive center of the First Affiliated Hospital of Anhui Medical University in Hefei, China, between April 2020 and December 2021 were included in our study. Blood (217 cases and 234 controls) and follicular fluid (182 cases and 203 controls) samples were collected from these subjects. The concentrations of Cd, Hg, As and Pb in the blood and follicular fluid were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Unconditional logistic regression models were used to assess the associations between Cd, Hg, As or Pb levels and the risk of endometriosis; Bayesian kernel machine regression (BKMR) was used to evaluate the combined effect of metals on the risk of endometriosis.

RESULTS

We found significant associations between blood concentrations of As (highest vs. lowest tertile: aOR = 5.53, 95 % CI: 2.97, 10.30), Cd (second vs. lowest tertile: aOR = 1.96, 95 % CI: 1.07, 3.58; highest vs. lowest tertile: aOR = 3.21, 95 % CI: 1.79, 5.77), Pb (highest vs. lowest tertile: aOR = 2.73, 95 % CI: 1.56, 4.78) and Hg (high-level group vs. low-level group: aOR = 13.10, 95 % CI: 6.74, 25.44; second vs. lowest tertile: aOR = 15.27, 95 % CI: 4.96, 46.97; highest vs. lowest tertile: aOR = 35.66, 95 % CI: 11.99, 106.08) and increased risk of endometriosis adjusting for confounders. Follicular fluid As (highest vs. lowest tertile: aOR = 2.42, 95 % CI: 1.35, 4.33), Hg (highest vs. lowest tertile: aOR = 1.86, 95 % CI: 1.05, 3.29), Cd (second vs. lowest tertile: aOR = 2.45, 95 % CI: 1.29, 4.65; highest vs. lowest tertile: aOR = 3.12, 95 % CI: 1.67, 5.83), and Pb (second vs. lowest tertile: aOR = 1.97, 95 % CI: 1.11, 3.52) concentrations were positively associated with endometriosis risk. The BKMR analyses showed linear associations between the metal mixtures and the risk of endometriosis. Both in blood and in follicular fluid, As exhibited the highest contribution.

CONCLUSION

The data from this study suggest that toxic metals, individually and as a mixture, play a role in the risk of endometriosis, thus providing a novel idea for endometriosis prevention.

Clear cell carcinoma of the abdominal wall: A case report with a review of the literature

Introduction and importance

Clear cell carcinoma of abdominal wall is a very rare and aggressive disease. It is mostly related to malignant transformation of abdominal wall endometriosis. This paper provides a new case report and a literature review of primitive abdominal wall clear cell carcinoma.

Case presentation

A 45-year-old woman with a history of a two previous caesarian section presented to the outpatient department with a tumor mass evolving since 10 years in the lower right quadrant of her abdomen. Imaging studies revealed a voluminous subcutaneous mass developing at the expense of the anterior abdominal wall. Surgical resection of the mass was performed. Histopathological examination along with immunohistochemical analysis were consistent with clear cell carcinoma. Biopsies of the endometrium and ovaries were performed and were negative for malignancy. The patient underwent therefore a hysterectomy with bilateral salpingo-oophorectomy which did not reveal any disease. The diagnosis of primitive clear cell carcinoma of the abdominal wall was then confirmed.

Clinical discussion

Primitive clear cell carcinoma of the abdominal wall is an extremely rare form of cancer with usually poor prognosis. Clinicians must be aware of the possibility of malignancy of any swelling mass occurring near or within a caesarean section scar.

Conclusion

Reporting more such cases is still needed to further progress in the understanding of this malignancy in addition to the development of treatment strategies.

•

Clear cell carcinoma (CCC) occurring in the anterior abdominal wall is an extremely rare but aggressive tumor.

•

It is usually secondary to malignant transformation of abdominal wall scar endometriosis.

•

Caesarean section is the major factor of developing abdominal wall scar endometriosis.

•

Treatment is mainly based on extensive surgery with free margins.

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.

The Comparison of Three Predictive Indexes to Discriminate Malignant Ovarian Tumors from Benign Ovarian Endometrioma: The Characteristics and Efficacy

This study aimed to evaluate the prediction efficacy of malignant transformation of ovarian endometrioma (OE) using the Copenhagen Index (CPH-I), the risk of ovarian malignancy algorithm (ROMA), and the R2 predictive index. This retrospective study was conducted at the Department of Gynecology, Nara Medical University Hospital, from January 2008 to July 2021. A total of 171 patients were included in the study. In the current study, cases were divided into three cohorts: pre-menopausal, post-menopausal, and a combined cohort. Patients with benign ovarian tumor mainly received laparoscopic surgery, and patients with suspected malignant tumors underwent laparotomy. Information from a review chart of the patients’ medical records was collected. In the combined cohort, a multivariate analysis confirmed that the ROMA index, the R2 predictive index, and tumor laterality were extracted as independent factors for predicting malignant tumors (hazard ratio (HR): 222.14, 95% confidence interval (CI): 22.27−2215.50, p < 0.001; HR: 9.80, 95% CI: 2.90−33.13, p < 0.001; HR: 0.15, 95% CI: 0.03−0.75, p = 0.021, respectively). In the pre-menopausal cohort, a multivariate analysis confirmed that the CPH index and the R2 predictive index were extracted as independent factors for predicting malignant tumors (HR: 6.45, 95% CI: 1.47−28.22, p = 0.013; HR: 31.19, 95% CI: 8.48−114.74, p < 0.001, respectively). Moreover, the R2 predictive index was only extracted as an independent factor for predicting borderline tumors (HR: 45.00, 95% CI: 7.43−272.52, p < 0.001) in the combined cohort. In pre-menopausal cases or borderline cases, the R2 predictive index is useful; while, in post-menopausal cases, the ROMA index is better than the other indexes.

Labile Heme and Heme Oxygenase-1 Maintain Tumor-Permissive Niche for Endometriosis-Associated Ovarian Cancer

Endometriosis, a painful gynecological condition accompanied by inflammation in women of reproductive age, is associated with an increased risk of ovarian cancer. We evaluated the role of peritoneal heme accumulated during menstrual cycling, as well as peritoneal and lesional macrophage phenotype, in promoting an oncogenic microenvironment. We quantified the heme-degrading enzyme, heme oxygenase-1 (HO-1, encoded by Hmox1) in normal peritoneum, endometriotic lesions and endometriosis-associated ovarian cancer (EAOC) of clear cell type (OCCC). HO-1 was expressed primarily in macrophages and increased in endometrioma and OCCC tissues relative to endometriosis and controls. Further, we compared cytokine expression profiles in peritoneal macrophages (PM) and peripheral blood mononuclear cells (PBMC) in women with endometriosis versus controls as a measure of a tumor-promoting environment in the peritoneum. We found elevated levels of HO-1 along with IL-10 and the pro-inflammatory cytokines (IL-1β, IL-16, IFNγ) in PM but not in PBMC from endometriosis patients. Using LysM-Cre:Hmox1flfl conditional knockout mice, we show that a deficiency of HO-1 in macrophages led to the suppression of growth of ID8 ovarian tumors implanted into the peritoneum. The restriction of ID8 ovarian tumor growth was associated with an increased number of Mac3+ macrophage and B cells in LysM-Cre:Hmox1flfl mice compared to controls. Functional experiments in ovarian cancer cell lines show that HO-1 is induced by heme. Low levels of exogenous heme promoted ovarian cancer colony growth in soft agar. Higher doses of heme led to slower cancer cell colony growth in soft agar and the induction of HO-1. These data suggest that perturbation of heme metabolism within the endometriotic niche and in cancer cells themselves may be an important factor that influences tumor initiation and growth.

Overall Survival and Related Factors of Advanced-stage Epithelial Ovarian Cancer Patients Underwent Debulking Surgery in Jakarta, Indonesia: A Single-center Experience

AIM: The worrisome prognosis of advanced-stage epithelial ovarian cancer (EOC) needs a new perspective from developing countries. Thus, we attempted to study the 5-year overall survival (OS) of advanced-stage EOC patients who underwent debulking surgery in an Indonesian tertiary hospital. METHODS: A retrospective study recruited forty-eight subjects between 2013 and 2015. We conducted multiple logistic regression analyses to predict risk factors leading to unwanted disease outcomes. The OS was evaluated through the Kaplan–Meier curve and Log-rank test. Cox proportional hazards regression examined prognostic factors of patients. RESULTS: Prominent characteristics of our patients were middle age (mean: 51.9 ± 8.9 years), obese, with normal menarche onset, multiparous, not using contraception, premenopausal, with serous EOC, and FIGO stage IIIC. The subjects mainly underwent primary debulking surgery (66.8%), with 47.9% of all individuals acquiring optimal results, 77.1% of patients treated had the residual disease (RD), and 52.1% got adjuvant chemotherapy. The risk factor for serous EOC was menopause (odds ratio [OR] = 4.82). The predictors of suboptimal surgery were serous EOC (OR = 8.25) and FIGO stage IV (OR = 11.13). The different OS and median survival were observed exclusively in RD, making it an independent prognostic factor (hazard ratio = 3.50). 5-year A five year OS and median survival for patients with advanced-stage EOC who underwent debulking surgery was 37.5% and 32 months, respectively. Optimal versus suboptimal debulking surgery yielded OS 43.5% versus 32% and median survival of 39 versus 29 months. Both optimal and suboptimal debulking surgery followed with chemotherapy demonstrated an OS 40% lower than those not administered (46.2% and 20%, respectively). The highest 5-year OS was in serous EOC (50%). Meanwhile, the most extended median survival was with mucinous EOC (45 months). CONCLUSION: Chemotherapy following optimal and suboptimal debulking surgery has the best OS among approaches researched in this study. RD is a significant prognostic factor among advanced-stage EOC. Suboptimal surgery outcomes can be predicted by stage and histological subtype.

Predictive factors of endometriosis progression into ovarian cancer

BACKGROUND

In recent years, the endometriosis has overcome a noteworthy renaissance in the recognition of its potential. In certain patients, a demonstrable malignant progression of ectopic foci leading to development of ovarian cancer is seen. The knowledge of endometriosis overthrow background into endometriosis associated ovarian cancer is of paramount importance for selection of patients at risk. The goal of the presented study was to review a malignant potential of the endometriosis and to specify predictive factors of endometriosis progression into ovarian cancer. Altogether 189 patients were included in the study. Conventional cytogenetics as well as measurement of transcriptional activity of CTNNB1 (β-catenin) and HIF1A (HIF1-α) genes were prospectively studied in 60 endometriosis patients and 50 control group patients. The retrospective histopathological analysis was performed in 19 endometriosis associated ovarian cancer patients and 60 patients with histologically confirmed endometriosis.

RESULTS

Five endometriosis patients showed a deviation from normal cytogenetics finding without affecting of their phenotype. In 6 cases of endometriosis associated ovarian cancer ectopic endometrium was not confirmed. The remaining 13 cases demonstrated either benign or atypical endometriosis or even structures of borderline carcinoma. Atypical endometriosis was histologically confirmed in 20% of 60 endometriosis patients. Determination of gene expression (CTNNB1, HIF1A) formed two subgroups. Transcriptionally incipient endometriosis subgroup with insignificant genes expression compared to control group. In transcriptionally evident endometriosis subgroup were genes expressions significantly higher compared to control group (p < 0.01) as well as transcriptionally incipient endometriosis subgroup (p < 0.05).

CONCLUSIONS

Significant structural abnormalities of chromosomes are not included in genetic rigging of endometriosis patients. Atypical endometriosis represents a histopathologically detectable intermediate of endometriosis progression. Determination of genes expression CTNNB1 and HIF1A helps to allocate risk patients with endometriosis where more precise management is needed.

Endometriosis and gynaecological cancers: molecular insights behind a complex machinery

Endometriosis is described as the presence of both endometrial glandular and stromal cells outside the uterine cavity. A major characterization of this disease is ectopic implantation of endometrial cells with increased migration. It is one of the leading causes of morbidity among premenopausal women, with a prevalence of 10-16% of women of reproductive age. Despite over century of intensive research, none of the current treatment options represents a real cure. Based on the current knowledge, endometriosis, particularly its atypical version, is considered to be a transitional form from benign disease to tumour. However, the exact mechanisms of this conversion are still not fully established.

Maternal-Fetal Outcomes in Women with Endometriosis and Shared Pathogenic Mechanisms

The connection between endometriosis and pregnancy outcomes is trending among the research topics. Until recently, endometriosis and its painful symptomatology were considered to be alleviated by pregnancy. However, these beliefs have shifted, as emerging literature has demonstrated the role of this condition in affecting pregnancy evolution. The underlying pathogenesis of endometriosis is still poorly understood, all the more when pregnancy complications are involved. Debatable opinions on endometriosis associated with obstetric complications exist because of the potential bias resulting from the heterogeneity of preceding evidence. This review aims to evaluate the connection between endometriosis and adverse pregnancy outcomes and their shared pathogenic mechanisms. We searched PubMed and EMBASE and focused on the studies that include placenta praevia, premature rupture of membranes, spontaneous preterm birth, gestational hypertension, preeclampsia, obstetric hemorrhages (ante- and postpartum bleeding, abruptio placentae), miscarriage, stillbirth, neonatal death, gestational diabetes mellitus, gestational cholestasis, small for gestational age, and their association with endometriosis. Not only the risks of emergence were highlighted, but also the pathogenic connections. Epigenetic alterations of some genes were found to be mirrored both in endometriosis and obstetric complications. This review issues a warning for providing increased attention to pregnant women with endometriosis and newborns as higher risks of preeclampsia, placental issues, and preterm deliveries are associated.

Antiproliferative and antiangiogenic effects of ammonium tetrathiomolybdate in a model of endometriosis

AIMS

Copper (Cu) is involved in the endometriosis progression. Herein, an experimental endometriosis model was used to evaluate whether its chelation with ammonium tetrathiomolybdate (TM) affects the proliferation and angiogenesis in endometriotic-like lesions and the participation of oxidative stress in these processes.

MAIN METHODS

Female C57BL/6 mice were divided into three groups: sham-operated mice, endometriosis-induced mice, and TM-treated endometriosis-induced mice. Each animal in the third group received 0.3 mg of TM/day in their drinking water from the postoperative 15th day. The samples were collected after one month of induced pathology. In peritoneal fluids, Cu and estradiol levels were determined by electrothermal atomic absorption spectrometry and electrochemiluminescence, respectively. Endometriotic-like lesions were processed for the analysis of cell proliferation by PCNA immunohistochemistry, the expression of angiogenic markers by RT-qPCR, the presence of endothelial cells by immunofluorescent staining, and oxidative stress applying spectrophotometric methods.

KEY FINDINGS

TM treatment decreased Cu and estradiol levels, which were increased by this pathology. In lesions, TM induced: (a) a decrease in tissue weight and volume, (b) a decrease in PCNA-positive cells, (c) antiangiogenic effects by decreasing the number of blood vessels, the mRNA expression of fibroblast growth factor 2 (Fgf2) and platelet-derived growth factor subunit B (Pdgfb), and the presence of endothelial cells, (d) a decrease in antioxidant activity and an increase in lipid peroxidation.

SIGNIFICANCE

TM is a highly effective antiproliferative and antiangiogenic agent, modulating oxidative imbalance in endometriosis. Its anti-endometriotic potential is an attractive feature of TM as a possible non-hormonal treatment.

A Novel Predictive Tool for Discriminating Endometriosis Associated Ovarian Cancer from Ovarian Endometrioma: The R2 Predictive Index

Simple Summary

Ovarian Endometrioma (OE) is a precancerous condition for endometriosis-associated ovarian cancer (EAOC). For many clinicians observing OE outpatients, setting the appropriate time for surgery can be a challenge because there is no suggestive milestone. Out of the fear of malignant transformation, many patients have surgery conducted according to respective faculty standards. This study aims to investigate a novel, noninvasive method not requiring an MRI device. This study partly helps to lift the above restrictions, and has the potential to suggest intervention-appropriate timing to the physician.

Abstract

Background: Magnetic resonance (MR) relaxometry provides a noninvasive tool to discriminate between ovarian endometrioma (OE) and endometriosis-associated ovarian cancer (EAOC), with a sensitivity and specificity of 86% and 94%, respectively. MRI models that can measure R2 values are limited, and the R2 values differ between MRI models. This study aims to extract the factors contributing to the R2 value, and to make a formula for estimating the R2 values, and to assess whether the R2 predictive index calculated by the formula could discriminate EAOC from OE. Methods: This retrospective study was conducted at our institution from November 2012 to February 2019. A total of 247 patients were included in this study. Patients with benign ovarian tumors mainly received laparoscopic surgery, and the patients suspected of having malignant tumors underwent laparotomy. Information from a chart review of the patients’ medical records was collected. Results: In the investigative cohort, among potential factors correlated with the R2 value, multiple regression analyses revealed that tumor diameter and CEA could predict the R2 value. In the validation cohort, multivariate analysis confirmed that age, CRP, and the R2 predictive index were the independent factors. Conclusions: The R2 predictive index is useful and valuable to the detection of the malignant transformation of endometrioma.

Endometriosis-associated cancer

Endometriosis will affect about 10% of the female population and not only can it significantly impact adversely on quality of life and result in infertility, but data are accumulating that malignant transformation is an important consideration. Endometriosis can be histologically typical or atypical, ovarian, superficial peritoneal or deep infiltrating. The precursor for malignant transformation appears to be the ovarian atypical endometriosis component. Ovarian cancer is the most important associated cancer, primarily endometrioid and clear cell cancer. These are the only subtypes wherein a direct clonal relationship between endometriosis, as a direct precursor, and cancer has been made. There is no substantive evidence to support an altered association of borderline cancers of the ovary, serous ovarian cancers and breast, endometrial or cervical cancers. This review provides an overview of the prevailing data pertaining to the molecular and genetic aberrations that accompany the transformation of atypical endometriosis to malignancy and the accumulated epidemiologic evidence which supports the association.

HO-1 and Heme: G-Quadruplex Interaction Choreograph DNA Damage Responses and Cancer Growth

Many anti-cancer therapeutics lead to the release of danger associated pattern molecules (DAMPs) as the result of killing large numbers of both normal and transformed cells as well as lysis of red blood cells (RBC) (hemolysis). Labile heme originating from hemolysis acts as a DAMP while its breakdown products exert varying immunomodulatory effects. Labile heme is scavenged by hemopexin (Hx) and processed by heme oxygenase-1 (HO-1, Hmox1), resulting in its removal and the generation of biliverdin/bilirubin, carbon monoxide (CO) and iron. We recently demonstrated that labile heme accumulates in cancer cell nuclei in the tumor parenchyma of Hx knockout mice and contributes to the malignant phenotype of prostate cancer (PCa) cells and increased metastases. Additionally, this work identified Hx as a tumor suppressor gene. Direct interaction of heme with DNA G-quadruplexes (G4) leads to altered gene expression in cancer cells that regulate transcription, recombination and replication. Here, we provide new data supporting the nuclear role of HO-1 and heme in modulating DNA damage response, G4 stability and cancer growth. Finally, we discuss an alternative role of labile heme as a nuclear danger signal (NDS) that regulates gene expression and nuclear HO-1 regulated DNA damage responses stimulated by its interaction with G4.

Validation of magnetic resonance relaxometry R2 value and cyst fluid iron level for diagnosis of ovarian endometrioma

Objectives

Magnetic resonance (MR) R2 relaxometry is a safe, noninvasive diagnostic modality for the evaluation of iron levels in the contents of ovarian cysts. The study aims to investigate the sensitivity and specificity of the two methods, R2 value and iron level, in diagnosing OMA patients in the validation set.

Methods

A prospective cohort study was conducted from 2013 to 2019. We investigated how R2 value was affected by iron-related compounds, antioxidants and bioelements in the cysts.

Results

The sensitivity and specificity of CF iron-based diagnosis of OMA was 96.6% and 95.4%, respectively. The sensitivity and specificity for R2 value in diagnosing OMA were 86.2% and 70.7%, respectively. The outcomes of the two tests were highly correlated (r = 0.758; P <0.001). The R2 value was positively correlated with CF levels of iron-related compounds and antioxidants. The R2 value was affected not only by iron ions but also by calcium ions.

Conclusion

Preoperative MR relaxometry may provide a noninvasive alternative to CF iron test in diagnosing OMA. The presence of paramagnetic cations in the cyst may be associated with reduced specificity.

Endometriosis-Associated Ovarian Cancer: The Origin and Targeted Therapy

Endometrial cysts (ECs) are thought to be the origin of endometriosis-associated ovarian cancer (EAOC). A hypothesis that the oxidative stress of iron in cysts causes “malignant transformation of ECs” has been proposed, but this has not been verified. Several population-based studies showed that endometriosis was a risk factor but did not reflect the “malignant transformation of ECs”. A review showed that most patients were diagnosed with EAOC early in monitoring following detection of ECs, and that these cases might have been cancer from the start. Epidemiologically, EAOC was reduced by hysterectomy rather than by cystectomy of ECs. Gene mutation analyses identified oncogenic mutations in endometriosis and normal endometrium and revealed that the same mutations were present at different endometriotic lesions. It was also shown that most of the gene mutations found in endometriosis occurred in normal endometrium. Taking together, EAOC might be caused by eutopic endometrial glandular epithelial cells with oncogenic mutations that have undergone menstrual blood reflux and engrafted in the ovary, rather than by low-risk ECs acquiring oncogenic mutations and becoming malignant. This review discusses the mechanisms of EAOC development and targeted therapy based on genetic variation in EAOC with a focus on eutopic endometrium.

Infertility and ovarian cancer risk: Evidence from nine prospective cohort studies

Epidemiological studies have investigated the relationship between infertility and the risk of ovarian cancer (OC); however, the results have been inconsistent. We therefore conducted the first meta-analysis to update and quantify the aforementioned association based on prospective cohort studies. Studies were identified by searching PubMed, EMBASE and Web of Science databases up to January 8, 2020. We extracted data from the studies and performed quality assessments. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Publication bias, and subgroup, meta-regression and sensitivity analyses were also conducted. Nine prospective cohort studies with a total of 10 383 OC cases and 6 278 830 participants were included in the present study. The summary RR of the association between infertility and the risk of OC was 1.51 (95% CI: 1.35-1.69), with low heterogeneity. Positive associations were observed in most subgroup analyses stratified by predefined factors, including region, duration of follow-up, study quality, causes of infertility, invasiveness of OC, infertility treatment status and adjustment of potential confounding parameters. No significant publication bias was detected. Our findings suggest that infertility in women were associated with an increased risk of OC.

Shared Molecular Features Linking Endometriosis and Obstetric Complications

Recent epidemiological research has shown the increased risk of adverse pregnancy outcomes in women with endometriosis compared with the general population. The aim of this review is to explore common pathophysiologic mechanisms between endometriosis and obstetric complications. A computerized literature search was performed to identify relevant studies. The search covered the period between January 2008 and October 2018. One of the potential mechanisms driving the initiation and progression of endometriosis is the accumulation of a variety of epigenetic changes in endometrial cells. Epigenetic control of gene expression which is considered to be responsible for the development of endometriosis is commonly seen in patients with preeclampsia, small for gestational age (SGA), or preterm birth. DLX5 and GATA3, paternally imprinted genes, and CDKN1C, a maternally imprinted gene, were aberrantly expressed in placenta tissues of the preeclampsia; CDKN1C, the growth inhibitor gene, was upregulated in human SGA placentas; and hypomethylation of PTGER2 would be associated with preterm birth. Preeclampsia, SGA, or preterm birth may share common epigenetic alterations with endometriosis, which raises the possibility that the occurrence of two conditions might be nonrandom. To date, however, there is a lack of evidence that links endometriosis and other obstetric complications, such as postpartum hemorrhage or placental abruption, at the epigenetic level. In conclusion, epigenetic changes may be a common hallmark of two conditions: endometriosis and obstetrical complications, such as preeclampsia, SGA, or preterm birth.

A diagnostic challenge of seromucinous borderline tumor: A case report

INTRODUCTION

Magnetic resonance (MR) relaxometry provides a noninvasive predictive tool to discriminate between benign ovarian endometrioma (OE) and endometriosis-associated ovarian cancer (EAOC). Transverse relaxation rate R2 value was determined using a single-voxel, multi-echo MR sequence (HISTO) by a 3T-MR system. R2 with cutoff value of 12.1 s was established to discriminate between benign and malignant tumors.

PATIENT CONCERNS

We present a case of a 39-year-old woman who was initially thought to be malignant transformation of endometriosis by diagnostic MR imaging of the vascularized solid components.

DIAGNOSIS

A R2 value of 42.62 s on MR relaxometry demonstrated that this case is non-malignant.

INTERVENTIONS

To confirm the diagnose, left salpingo-oophorectomy by laparoscopic surgery was performed.

OUTCOMES

Histopathological results revealed seromucinous borderline tumor (SMBT). Our experience suggests that preoperative MR relaxometry may be useful for discriminating "borderline (SMBT)" from "malignancy (EAOC)." Furthermore, immunohistochemical studies of this case demonstrated ovarian SMBT cells were positive for estrogen receptor, progesterone receptor, and hepatocyte nuclear factor-1beta. A similar expression pattern was also observed in patients with benign OE.

LESSONS

In many respects, SMBT characteristics differ from those of EAOC but resemble those of benign OE. MR relaxometry unveils a new clinical approach as an adjunctive modality for discriminating SMBT from EAOC.

Endometriosis and cancer

Endometriosis, characterized by the presence of extra-uterine endometrium, is a common gynecologic disorder in reproductive-age women. Although the detailed molecular mechanism of etiology remains unelucidated, recent studies have gradually revealed both genetic and epigenetic backgrounds of the development of endometriosis. In clinical practice, endometriosis has been recognized as a precursor lesion of several types of malignancies and endometriosis-associated carcinoma. An imbalance between reactive oxygen species and local antioxidants has been reported to contribute to the development of endometriosis-associated carcinoma as well as the pathophysiology of this disease through a systemic inflammatory response in the peritoneal cavity. This review mainly presents an epidemiology, possible etiology of endometriosis, precursor lesions, molecular features, and the association between the microenvironmental accumulations of oxidative stress in endometriosis-associated ovarian cancer progression.

The risk of breast and gynecological cancer in women with a diagnosis of infertility: a nationwide population-based study

Some studies have suggested that infertility is a risk factor for endometrial, ovarian and breast cancer. The study aimed to create a comprehensive picture of the association between infertility and the risk of ovarian, endometrial and breast cancer, and whether any association could be explained by ovulatory disturbances, endometriosis or nulliparity. In a population-based cohort of 2,882,847 women, cox regression analysis was used to investigate cancer incidence among infertile women. Overall, infertility was associated with a higher incidence rate of ovarian (adjusted hazard ratio [aHR] 1.53, 95% confidence interval [CI] 1.38-1.71) and endometrial cancer (aHR 1.25, 95% CI 1.11-1.40), but not of breast cancer (aHR 0.96, 95% CI 0.92-1.01). Ovarian cancer incidence was higher in women diagnosed with endometriosis, and in nulliparous women with ovulatory disturbances, compared to women with none of the diagnoses. Endometrial cancer incidence was higher in women with ovulatory disturbances, but not in women with endometriosis. These findings suggest that infertility could have long-term consequences of importance to physicians and public health workers.

Clinical significance of M2 macrophages expressing heme oxygenase-1 in malignant transformation of ovarian endometrioma

Malignant transformation of endometriosis is a rare and still poorly understood event, but is associated with the distortion of the pro-oxidant and anti-oxidant balance. The aim of the present study was to quantify the numbers of macrophages polarized as M1 or M2 phenotypes and the expression of heme oxygenase (HO)-1 in tissue sections from patients with benign ovarian endometrioma (OE) and its malignant transformation (endometriosis-associated ovarian cancer, EAOC). We performed a retrospective study at the Department of Gynecology, Nara Medical University hospital from December 2012 to March 2015. This study included 53 patients with OE (n = 33) and EAOC (n = 20), and we evaluated polarized functional status of macrophages by immunohistochemical staining of CD68, CD11c, CD163 and HO-1. The number of the M1 phenotype (CD11c⁺, p = 0.001) and the M2 phenotype (CD163⁺, p = 0.009) was significantly lower in EAOC patients than in OE patients. Analyzing the correlations between the studied markers, the expression of CD68, CD11c, and CD163 proteins significantly correlated with each other (p < 0.001). The number of M2 phenotypes expressing HO-1 was significantly decreased in the EAOC group, compared with the OE group (P < 0.001), demonstrating sustained downregulation of an antioxidant marker, HO-1, in EAOC. In conclusion, reduced number of M2 macrophages expressing HO-1 may have an important role in promoting malignant transformation of OE.

Comparison of redox parameters in ovarian endometrioma and its malignant transformation

The present study aimed to evaluate the levels of oxidative stress and antioxidant markers in benign endometrioma (OE) and its malignant transformation [endometriosis-associated ovarian cancer (EAOC)] by measuring 8-hydroxy-2-deoxyguanosine (8-OHdG), heme oxygenase-1 (HO-1) and total antioxidant capacity (TAC/Heme-iron) alterations associated with disease progression. Cyst fluid samples from 44 patients with OE and 14 patients with EAOC were studied using an enzyme-linked immunosorbent assay. A χ² test, t-test and Pearson correlation test were performed using SPSS version 22.0. The cut-off point, sensitivity and specificity of each marker for EAOC diagnosis were evaluated by receiver operating characteristic curve analysis. Cyst fluid 8-OHdG and HO-1 levels in the EAOC group were significantly decreased compared with the OE subjects (P=0.013 and P<0.001, respectively). The levels of TAC/Heme-iron in patients with EAOC were significantly higher compared with those in the OE subjects (P<0.001). The present study demonstrated a positive correlation between 8-OHdG and HO-1 levels (P=0.012). HO-1 exhibited the highest discriminant value for EAOC (Area Under the Curve=0.901). The optimal cut-off point of HO-1 for the diagnosis of EAOC was 2.314 ng/ml, with a sensitivity and specifity of 95.2 and 85.7%, respectively. The present study revealed a clear separation between the overall redox state in OE and EAOC. It was concluded that characteristic alterations in important factors in redox may be helpful for understanding the pathogenesis of the malignant transformation of endometriosis.

The Role of Oxidative Stress and Membrane Transport Systems during Endometriosis: A Fresh Look at a Busy Corner

Endometriosis is a condition characterized by the presence of endometrial tissue outside the uterine cavity, leading to a chronic inflammatory reaction. It is one of the most widespread gynecological diseases with a 10-15% prevalence in the general female population, rising up to 30-45% in patients with infertility. Although it was first described in 1860, its etiology and pathogenesis are still unclear. It is now accepted that inflammation plays a central role in the development and progression of endometriosis. In particular, it is marked by an inflammatory process associated with the overproduction of an array of inflammatory mediators such as prostaglandins, metalloproteinases, cytokines, and chemokines. In addition, the growth and adhesion of endometrial cells in the peritoneal cavity due to reactive oxygen species (ROS) and free radicals lead to disease onset, its ensuing symptoms-among which pain and infertility. The aim of our review is to evaluate the role of oxidative stress and ROS in the pathogenesis of endometriosis and the efficacy of antioxidant therapy in the treatment and mitigation of its symptoms.

Sequential molecular changes and dynamic oxidative stress in high-grade serous ovarian carcinogenesis

The mechanism of high-grade serous ovarian cancer (HGSC) development remains elusive. This review outlines recent advances in the understanding of sequential molecular changes associated with the development of HGSC, as well as describes oxidative stress-induced genomic instability and carcinogenesis. This article reviews the English language literature between 2005 and 2017. Clinicopathological features analysis provides a sequential progression of fallopian tubal epithelium to precursor lesions to type 2 HGSC. HGSC may develop over a long time after incessant ovulation and repeated retrograde menstruation via stepwise accumulation of genetic alterations, including PAX2, ALDH1A1, STMN1, EZH2 and CCNE1, which confer positive selection of cells with growth advantages through acquiring driver mutations such as BRCA1/2, p53 or PTEN/PIK3CA. Haemoglobin and iron-induced oxidative stress leads to the emergence of genetic alterations in fallopian tubal epithelium via increased DNA damage and impaired DNA repair. Serous tubal intraepithelial carcinoma (STIC), the likely precursor of HGSC, may be susceptible to DNA double-strand breaks, exhibit DNA replication stress and increase genomic instability. The induction of genomic instability is considered to be a driving mechanism of reactive oxygen species (ROS)-induced carcinogenesis. HGSC exemplifies the view of stepwise cancer development. We describe how genetic alterations emerge during HGSC carcinogenesis related to oxidative stress.

Oxidative Stress and Endometriosis: A Systematic Review of the Literature

Endometriosis is one of the most common gynaecologic diseases in women of reproductive age. It is characterized by the presence of endometrial tissue outside the uterine cavity. The women affected suffer from pelvic pain and infertility. The complex etiology is still unclear and it is based on three main theories: retrograde menstruation, coelomic metaplasia, and induction theory. Genetics and epigenetics also play a role in the development of endometriosis. Recent studies have put the attention on the role of oxidative stress, defined as an imbalance between reactive oxygen species (ROS) and antioxidants, which may be implicated in the pathophysiology of endometriosis causing a general inflammatory response in the peritoneal cavity. Reactive oxygen species are intermediaries produced by normal oxygen metabolism and are inflammatory mediators known to modulate cell proliferation and to have deleterious effects. A systematic review was performed in order to clarify the different roles of oxidative stress and its role in the development of endometriosis. Several issues have been investigated: iron metabolism, oxidative stress markers (in the serum, peritoneal fluid, follicular fluid, peritoneal environment, ovarian cortex, and eutopic and ectopic endometrial tissue), genes involved in oxidative stress, endometriosis-associated infertility, and cancer development.

Iron overload and altered iron metabolism in ovarian cancer

Iron is an essential element required for many processes within the cell. Dysregulation in iron homeostasis due to iron overload is detrimental. This nutrient is postulated to contribute to the initiation of cancer; however, the mechanisms by which this occurs remain unclear. Defining how iron promotes the development of ovarian cancers from precursor lesions is essential for developing novel therapeutic strategies. In this review, we discuss (1) how iron overload conditions may initiate ovarian cancer development, (2) dysregulated iron metabolism in cancers, (3) the interplay between bacteria, iron, and cancer, and (4) chemotherapeutic strategies targeting iron metabolism in cancer patients.