Contents of endometriotic cysts, especially the high concentration of free iron, are a possible cause of carcinogenesis in the cysts through the iron-induced persistent oxidative stress

Endometriosis, a common but enigmatic disease with many faces: current concept of pathophysiology, and diagnostic strategy

Endometriosis is a benign, common, but controversial disease due to its enigmatic etiopathogenesis and biological behavior. Recent studies suggest multiple genetic, and environmental factors may affect its onset and development. Genomic analysis revealed the presence of cancer-associated gene mutations, which may reflect the neoplastic aspect of endometriosis. The management has changed dramatically with the development of fertility-preserving, minimally invasive therapies. Diagnostic strategies based on these recent basic and clinical findings are reviewed. With a focus on the presentation of clinical cases, we discuss the imaging manifestations of endometriomas, deep endometriosis, less common site and rare site endometriosis, various complications, endometriosis-associated tumor-like lesions, and malignant transformation, with pathophysiologic conditions.

Diagnostic Value of Menstrual Blood Lipidomics in Endometriosis: A Pilot Study

Endometriosis is a prevalent chronic inflammatory disease characterized by a considerable delay between initial symptoms and diagnosis through surgery. The pressing need for a timely, non-invasive diagnostic solution underscores the focus of current research efforts. This study examines the diagnostic potential of the menstrual blood lipidome. The lipid profile of 39 samples (23 women with endometriosis and 16 patients in a control group) was acquired using reverse-phase high-performance liquid chromatography-mass spectrometry with LipidMatch processing and identification. Profiles were normalized based on total ion counts. Significant differences in lipids were determined using the Mann-Whitney test. Lipids for the diagnostic model, based on logistic regression, were selected using a combination of variance importance projection filters and Akaike information criteria. Levels of ceramides, sphingomyelins, cardiolipins, triacylglycerols, acyl- and alkenyl-phosphatidylethanolamines, and alkenyl-phosphatidylcholines increased, while acyl- and alkyl-phosphatidylcholines decreased in cases of endometriosis. Plasmenylphosphatidylethanolamine PE P-16:0/18:1 and cardiolipin CL 16:0_18:0_22:5_22:6 serve as marker lipids in the diagnostic model, exhibiting a sensitivity of 81% and specificity of 85%. The diagnostic approach based on dried spots of menstrual blood holds promise as an alternative to traditional non-invasive methods for endometriosis screening.

Occult clear cell carcinoma arising from oxidative stress‑exposed cystic adenomyosis: A case report

Although adenomyosis is a benign uterine disease, it can turn malignant in rare instances. Cystic adenomyosis is a rare variation of adenomyosis, arising from which 8 cases of clear cell carcinoma have been reported. However, to the best of our knowledge, there have been no previous reports describing the mechanism by which clear cell carcinoma develops from cystic adenomyosis. The present report documents a case of a 73-year-old woman who was referred to Kanazawa University Hospital (Kanazawa, Japan) because of cystic adenomyosis, with a solid part inside the cyst. The patient was diagnosed with cystic adenomyosis at Shonan Obstetrics and Gynecology Hospital (Hakusan, Japan) 17 years prior; however, the size of the cyst increased after menopause. Therefore, malignant transformation was suspected, which warranted simple abdominal hysterectomy and bilateral salpingo-oophorectomy. The final diagnosis of the present case was uterine corpus cancer, clear cell carcinoma, stage IA. Immunohistochemical staining revealed that the normal and transitional atypical epithelial cells lining the cyst wall, in addition to the clear cell carcinoma cells (which were inside mural nodules located on the cyst wall), were positive for 8-hydroxy-20-deoxyguanosine. This observation suggested the presence of chronic oxidative stress around the cystic adenomyosis. Therefore, the present case suggests the possible involvement of chronic oxidative stress in the malignant transformation of cystic adenomyosis to clear cell carcinoma. This mechanism of malignant transformation of cystic adenomyosis appears to be similar to that of the malignant transformation of endometriotic cysts. Therefore, if the size of the cystic adenomyosis increases after menopause or if the solid part appears in the cyst in future cases, then the possibility of malignant transformation should be considered.

Redox-Regulated Iron Metabolism and Ferroptosis in Ovarian Cancer: Molecular Insights and Therapeutic Opportunities

Ovarian cancer (OC), known for its lethality and resistance to chemotherapy, is closely associated with iron metabolism and ferroptosis-an iron-dependent cell death process, distinct from both autophagy and apoptosis. Emerging evidence suggests that dysregulation of iron metabolism could play a crucial role in OC by inducing an imbalance in the redox system, which leads to ferroptosis, offering a novel therapeutic approach. This review examines how disruptions in iron metabolism, which affect redox balance, impact OC progression, focusing on its essential cellular functions and potential as a therapeutic target. It highlights the molecular interplay, including the role of non-coding RNAs (ncRNAs), between iron metabolism and ferroptosis, and explores their interactions with key immune cells such as macrophages and T cells, as well as inflammation within the tumor microenvironment. The review also discusses how glycolysis-related iron metabolism influences ferroptosis via reactive oxygen species. Targeting these pathways, especially through agents that modulate iron metabolism and ferroptosis, presents promising therapeutic prospects. The review emphasizes the need for deeper insights into iron metabolism and ferroptosis within the redox-regulated system to enhance OC therapy and advocates for continued research into these mechanisms as potential strategies to combat OC.

Activation of cGAS/STING Drives Inflammation and Cellular Senescence of Macrophages in Ovarian Endometrioma Induced by Endometriotic Cyst Fluid

Ovarian endometrioma (OE) is a common gynecological condition characterized by the formation of "chocolate cysts". Recent research indicates that the cyst fluid acts as a "toxic environment" for the ovary and plays a significant role in the development of OE, with macrophages being pivotal. However, the specific molecular and cellular mechanisms of it are not fully understood. In this study, clinical samples are integrated, single-cell sequencing, in vivo and in vitro experimental models to comprehensively investigate the effects of OE fluid on ovarian function and the mechanisms of it. Combined with bioinformatics analysis and experimental validation, the findings demonstrate that OE fluid can cause ovarian function decline, which associated with inflammatory response, and mitochondrial dysfunction and cellular senescence, while activating the cGAS/STING signaling pathway. As a STING inhibitor, H-151 effectively alleviates ovarian dysfunction, inflammatory state and cell apoptosis induced by OE fluid. Furthermore, it is also discovered that H-151 can inhibit OE fluid-induced mitochondrial dysfunction and cellular senescence. These findings provide important theoretical and experimental foundations for further research and development of STING inhibitors as potential drugs for treating ovarian dysfunction.

The "Road" to Malignant Transformation from Endometriosis to Endometriosis-Associated Ovarian Cancers (EAOCs): An mTOR-Centred Review

Ovarian cancer is an umbrella term covering a number of distinct subtypes. Endometrioid and clear-cell ovarian carcinoma are endometriosis-associated ovarian cancers (EAOCs) frequently arising from ectopic endometrium in the ovary. The mechanistic target of rapamycin (mTOR) is a crucial regulator of cellular homeostasis and is dysregulated in both endometriosis and endometriosis-associated ovarian cancer, potentially favouring carcinogenesis across a spectrum from benign disease with cancer-like characteristics, through an atypical phase, to frank malignancy. In this review, we focus on mTOR dysregulation in endometriosis and EAOCs, investigating cancer driver gene mutations and their potential interaction with the mTOR pathway. Additionally, we explore the complex pathogenesis of transformation, considering environmental, hormonal, and epigenetic factors. We then discuss postmenopausal endometriosis pathogenesis and propensity for malignant transformation. Finally, we summarize the current advancements in mTOR-targeted therapeutics for endometriosis and EAOCs.

MR Relaxometry for Discriminating Malignant Ovarian Cystic Tumors: A Prospective Multicenter Cohort Study

BACKGROUND

Endometriosis-associated ovarian cancer (EAOC) is a well-known type of cancer that arises from ovarian endometrioma (OE). OE contains iron-rich fluid in its cysts due to repeated hemorrhages in the ovaries. However, distinguishing between benign and malignant tumors can be challenging. We conducted a retrospective study on magnetic resonance (MR) relaxometry of cyst fluid to distinguish EAOC from OE and reported that this method showed good accuracy. The purpose of this study is to evaluate the accuracy of a non-invasive method in re-evaluating pre-surgical diagnosis of malignancy by a prospective multicenter cohort study.

METHODS

After the standard diagnosis process, the R2 values were obtained using a 3T system. Data on the patients were then collected through the Case Report Form (CRF). Between December 2018 and March 2023, six hospitals enrolled 109 patients. Out of these, 81 patients met the criteria required for the study.

RESULTS

The R2 values calculated using MR relaxometry showed good discriminating ability with a cut-off of 15.74 (sensitivity 80.6%, specificity 75.0%, AUC = 0.750, p < 0.001) when considering atypical or borderline tumors as EAOC. When atypical and borderline cases were grouped as OE, EAOC could be distinguished with a cut-off of 16.87 (sensitivity 87.0%, specificity 61.1%).

CONCLUSIONS

MR relaxometry has proven to be an effective tool for discriminating EAOC from OE. Regular use of this method is expected to provide significant insights for clinical practice.

Malignancy in Abdominal Wall Endometriosis: Is There a Way to Avoid It? A Systematic Review

Background: Malignant-associated abdominal wall endometriosis (AWE) is a rare pathology, likely to occur in 1% of scar endometriosis. The objectives of this study were to update the evidence on tumor degeneration arising from AWE to notify about the clinical characteristics, the different treatments offered to patients and their outcomes. Methods: A comprehensive systematic review of the literature was conducted. PubMed, Embase and Cochrane Library databases were used. Prospero (ID number: CRD42024505274). Results: Out of the 152 studies identified, 63 were included, which involved 73 patients. The main signs and symptoms were a palpable abdominal mass (85.2%) and cyclic pelvic pain (60.6%). The size of the mass varied between 3 and 25 cm. Mean time interval from the first operation to onset of malignant transformation was 20 years. Most common cancerous histological types were clear cell and endometrioid subtypes. Most widely accepted treatment is the surgical resection of local lesions with wide margins combined with adjuvant chemotherapy. The prognosis for endometriosis-associated malignancy in abdominal wall scars is poor, with a five-year survival rate of around 40%. High rates of relapse have been reported. Conclusions: Endometrial implants in the abdominal wall should be considered as preventable complications of gynecological surgeries. Special attention should be paid to women with a history of cesarean section or uterine surgery.

Endometriosis-Associated Ovarian Cancer: From Molecular Pathologies to Clinical Relevance

Endometriosis is a chronic condition affecting reproductive-aged women, characterized by the growth of ectopic endometrial tissue. Despite being benign, endometriosis is associated with an increased risk of certain cancers, including endometriosis-associated ovarian cancer (EAOC). Ovarian cancer is rare, but more common in women with endometriosis, particularly endometrioid and clear-cell carcinomas. Factors such as hormonal imbalance, reproductive history, environmental exposures, and genetic predisposition contribute to the malignant transformation of endometriosis. Thus, understanding potential risk factors causing malignancy is crucial. Over the past few decades, various genetic mutations, microRNAs, as well as tumor microenvironmental factors have been identified, impacting pathways like PI3K/AKT/mTOR, DNA repair mechanisms, oxidative stress, and inflammation. Thus, this review aims to summarize molecular studies involved in EAOC pathogenesis as potential therapeutic targets. However, further research is needed to better understand the molecular and environmental factors driving EAOC development, to target the susceptibility of endometriotic lesions to malignant progression, and to identify effective therapeutic strategies.

Endometriosis-Related Ovarian Cancer: Where Are We Now? A Narrative Review towards a Pragmatic Approach

BACKGROUND

Endometriosis affects more than 10% of reproductive-aged women, causing pelvic pain and infertility. Despite the benign nature of endometriosis, ovarian endometriomas carry a higher risk of developing endometrioid carcinomas (EnOCs) and clear cell ovarian carcinomas (CCCs). Atypical endometriosis, defined as cytological atypia resembling intraepithelial cancer, is considered the precursor of endometriosis-associated ovarian cancer (EAOC). This narrative review aims to provide an overview of EAOC, proposing a practical approach to clinical and therapeutic decision making.

METHODS

An electronic literature search was conducted from inception up to January 2023, using the MEDLINE database via PubMed to evaluate the existing literature on EAOC, including its pathogenesis, the diagnostic process, and the therapeutic possibilities, with articles not relevant to the topic or lacking scientific merit being excluded.

RESULTS

Eighty-one articles were included in the review to present the current state of the art regarding EAOC. A pragmatic clinical flowchart is proposed to guide therapeutic decisions and improve patient outcomes.

CONCLUSIONS

Endometriosis patients may have an increased risk of developing EAOC (either EnOC or CCC). Despite not being fully accepted, the concept of AE may reshape the endometriosis-ovarian cancer relationship. Further research is needed to understand the unaddressed issues.

Chapter 11. Endometriosis-related complications in women undergoing in-vitro fertilization

As a chronic inflammatory disease, endometriosis generates fibrosis and anatomic distortion, which add extra-challenges to assisted reproductive technology cycles and requires a personalized approach. Patients with endometriomas have significantly decreased ovarian reserve and the ultrasound examination tends to be challenging, possibly underestimating follicle counts. It is crucial to assess the feasibility of oocyte retrieval procedure during the initial examination of the patient, as the distortion of the pelvic anatomy, the presence of hydrosalpinges and endometriomas might render the procedure difficult and increase the risk of complications. Possible injury to adjacent organs and risk of infection must be considered. Assisted reproductive technology seems to have limited or no impact on endometriosis recurrence, pain symptom progression or the size of endometrioma.

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.

Iron deposition in ovarian endometriosis evaluated by magnetic resonance imaging R2* correlates with ovarian function

RESEARCH QUESTION

Does iron overload in patients with endometriosis affect ovarian function? Can a method be developed to visually reflect this?

DESIGN

Magnetic resonance imaging (MRI) R2* was used to evaluate the correlation between iron deposition of ovarian and anti-Müllerian hormone (AMH) in patients with endometriosis. All patients underwent T2* MRI scanning. Serum AMH levels were measured preoperatively. The area of focal iron deposition, iron content of the cystic fluid and AMH levels between the endometriosis and control groups were compared using non-parametric tests. The effects of iron overload on AMH secretion in mouse ovarian granulosa cells were investigated by adding different concentrations of ferric citrate to the medium.

RESULTS

A significant difference was found between endometriosis and control groups in area of iron deposition (P < 0.0001), cystic fluid iron content (P < 0.0001), R2* of lesions (P < 0.0001) and R2* of the cystic fluid (P < 0.0001). Negative correlations were found between serum AMH levels and R2* of cystic lesions in patients with endometriosis aged 18-35 years (rs = -0.6484, P < 0.0001), and between serum AMH levels and R2* of cystic fluid (rs = -0.5074, P = 0.0050). Transcription level (P < 0.0005) and secretion level (P < 0.005) of AMH significantly decreased with the increase in iron exposure.

CONCLUSION

Iron deposits can impair ovarian function, which is reflected in MRI R2*. Serum AMH levels and R2* of cystic lesions or fluid in patients aged 18-35 years had a negative correlation with endometriosis. R2* can be used to reflect the changes of ovarian function caused by iron deposition.

Exploring the cellular and molecular differences between ovarian clear cell carcinoma and high-grade serous carcinoma using single-cell RNA sequencing and GEO gene expression signatures

The two most prevalent subtypes of epithelial ovarian carcinoma (EOC) are ovarian clear cell carcinoma (OCCC) and high-grade serous ovarian carcinoma (HGSC). Patients with OCCC have a poor prognosis than those with HGSC due to chemoresistance, implying the need for novel treatment target. In this study, we applied single-cell RNA sequencing (scRNA-seq) together with bulk RNA-seq data from the GEO (Gene Expression Omnibus) database (the GSE189553 dataset) to characterize and compare tumor heterogeneity and cell-level evolution between OCCC and HGSC samples. To begin, we found that the smaller proportion of an epithelial OCCC cell subset in the G2/M phase might explain OCCC chemoresistance. Second, we identified a possible pathogenic OCCC epithelial cell subcluster that overexpresses LEFTY1. Third, novel biomarkers separating OCCC from HGSC were discovered and subsequently validated on a wide scale using immunohistochemistry. Amine oxidase copper containing 1 (AOC1) was preferentially expressed in OCCC over HGSC, while S100 calcium-binding protein A2 (S100A2) was detected less frequently in OCCC than in HGSC. In addition, we discovered that metabolic pathways were enriched in the epithelial compartment of the OCCC samples. In vitro experiments verified that inhibition of oxidative phosphorylation or glycolysis pathways exerted direct antitumor effects on both OCCC and HGSC cells, while targeting glutamine metabolism or ferroptosis greatly attenuated chemosensitivity only in OCCC cells. Finally, to determine whether there were any variations in immune cell subsets between OCCC and HGSC, data from scRNA-seq and mass cytometry were pooled for analysis. In summary, our work provides the first holistic insights into the cellular and molecular distinctions between OCCC and HGSC and is a valuable source for discovering new targets to leverage in clinical treatments to improve the poor prognosis of patients with OCCC.

Clinical perspectives of rare ovarian tumors: clear cell ovarian cancer

Ovarian clear cell carcinoma (OCCC) is a rare and distinct histological type of epithelial ovarian carcinoma in terms of its histopathological, clinical and genetic features. Patients with OCCC are younger and diagnosed at earlier stages than those with the most common histological type-high-grade serous carcinoma. Endometriosis is considered a direct precursor of OCCC. Based on preclinical data, the most frequent gene alternations in OCCC are mutations of AT-rich interaction domain 1A and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha. The prognosis of patients with early-stage OCCC is favorable, whereas patients at an advanced stage or who have the recurrent disease have a dismal prognosis due to OCCC's resistance to standard platinum-based chemotherapy. Despite a lower rate of response due to its resistance to standard platinum-based chemotherapy, the treatment strategy for OCCC resembles that of high-grade serous carcinoma, which includes aggressive cytoreductive surgery and adjuvant platinum-based chemotherapy. Alternative treatment strategies, including biological agents based on molecular characteristics specific to OCCC, are urgently needed. Furthermore, due to its rarity, well-designed collaborative international clinical trials are needed to improve oncologic outcomes and the quality of life in patients with OCCC.

The role of iron in the pathogenesis of endometriosis: a systematic review

STUDY QUESTION

What is the role of iron in the pathophysiology of endometriosis?

SUMMARY ANSWER

Iron excess is demonstrated wherever endometriotic tissues are found and is associated with oxidative stress, an inflammatory micro-environment, and cell damage; the iron-mediated oxidative stress is independently linked to subfertility, symptom severity, and malignant transformation.

WHAT IS KNOWN ALREADY

Iron is found in excess in endometriotic tissues, and multiple mechanisms have been studied and posited to explain this. It is clear that iron excess plays a vital role in promoting oxidative stress and cell damage. The evidence base is large, but no comprehensive reviews exist to summarize our understanding and highlight the overarching themes to further our understanding and suggest future directions of study for the field.

STUDY DESIGN SIZE DURATION

This systematic review with a thematic analysis retrieved studies from the PubMed, Embase, Web of Science, and Cochrane Library databases and searches were conducted from inception through to August 2022. Human and animal studies published in the English language were included and identified using a combination of exploded MeSH terms ('Iron' and 'Endometriosis') and free-text search terms ('Iron', 'Ferric', 'Ferrous', 'Endometriosis', 'Endometrioma').

PARTICIPANTS/MATERIALS SETTING METHODS

This review was reported in accordance with the PRISMA guidelines. All studies reporting original data concerning the role of iron or iron complexes in the pathophysiology of endometriosis were included. Studies that did not report original data or provided a review of the field were excluded. Bias analysis was completed for each included study by using the Newcastle-Ottawa scoring system.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 776 records identified and these were screened down to 53 studies which met the eligibility criteria, including 6 animal and 47 human studies, with 3556 individual participants. Iron excess is demonstrated in various tissues and fluids, including ovarian endometriomas, ovarian follicles, ectopic endometriotic lesions, and peritoneal fluid. Markers of oxidative stress are strongly associated with high iron levels, and aberrant expression of iron-transport proteins has been demonstrated. Abnormal resistance to ferroptosis is likely. Iron-mediated oxidative stress is responsible for a pro-inflammatory micro-environment and is linked to subfertility, symptom severity, and, possibly, malignant transformation.

LIMITATIONS REASONS FOR CAUTION

A minority of the included studies were of objectively low quality with a high risk of bias and may lead to misleading conclusions. Additionally, multiple studies failed to appropriately characterize the included patients by known confounding variables, such as menstrual cycle phase, which may introduce bias to the findings.

WIDER IMPLICATIONS OF THE FINDINGS

Current literature depicts a central role of aberrant iron mechanics and subsequent oxidative stress in endometriosis. It is likely that iron excess is at least partly responsible for the persistence and proliferation of ectopic endometriotic lesions. As such, iron mechanics represent an attractive target for novel therapeutics, including iron chelators or effectors of the iron-oxidative stress pathway. There are significant gaps in our current understanding, and this review highlights and recommends several topics for further research. These include the role of iron chelation, resistance to ferroptosis, the relationship between iron excess and localized hypoxia, systemic iron pathophysiology in endometriosis, and the role of oxidative stress in malignant transformation.

STUDY FUNDING/COMPETING INTERESTS

J.W. and S.G.P. are supported by clinical fellowships at Liverpool University Hospital NHS Foundation trust. No additional funding was requested or required for the completion of this work. C.J.H. is supported by a Wellbeing of Women project grant (RG2137). D.K.H. is supported by a Wellbeing of Women project grant (RG2137) and an MRC clinical research training fellowship (MR/V007238/1). The authors have no conflicts of interest to declare.

REGISTRATION NUMBER

A protocol was prospectively registered with the PROSPERO database in August 2021 (CRD42021272818).

The Silent Threat to Women's Fertility: Uncovering the Devastating Effects of Oxidative Stress

Oxidative stress (OS), which arises through an imbalance between the formation of reactive oxygen species (ROS) and antioxidant defenses, plays a key role in the pathophysiology of female infertility, with the latter constituting just one of a number of diseases linked to OS as a potential cause. The aim of the present article is to review the literature regarding the association between OS and female infertility. Among the reproductive diseases considered are endometriosis and polycystic ovary syndrome (PCOS), while environmental pollutants, lifestyle variables, and underlying medical conditions possibly resulting in OS are additionally examined. Current evidence points to OS likely contributing to the pathophysiology of the above reproductive disorders, with the amount of damage done by OS being influenced by such variables as duration and severity of exposure and the individual's age and genetic predisposition. Also discussed are the processes via which OS may affect female fertility, these including DNA damage and mitochondrial dysfunction. Finally, the last section of the manuscript contains an evaluation of treatment options, including antioxidants and lifestyle modification, capable of minimizing OS in infertile women. The prime message underlined by this review is the importance of considering OS in the diagnosis and treatment of female infertility. Further studies are, nevertheless required to identify the best treatment regimen and its ideal duration.

Mechanism of Cell Death by Combined Treatment with an xCT Inhibitor and Paclitaxel: An Alternative Therapeutic Strategy for Patients with Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a rare subtype of epithelial ovarian carcinoma that responds poorly to chemotherapy. Glutathione (GSH) is a primary antioxidant, which protects cells against reactive oxygen species (ROS). High levels of GSH are related to chemotherapeutic resistance. The glutamine/cystine transporter xCT is essential for intracellular GSH synthesis. However, whether xCT inhibition can overcome the resistance to chemotherapeutic agents in OCCC remains unclear. This study demonstrated that combined treatment with paclitaxel (PTX) and the xCT inhibitor sulfasalazine (SAS) significantly enhanced cytotoxicity more than the individual drugs did in OCCC cells. Treatment with PTX and SAS induced apoptosis more effectively than did individual drug treatments in the cells with significant generation of ROS. Moreover, combined treatment with PTX and SAS induced ferroptosis in the cells with low expression of glutathione peroxidase (GPx4), high levels of intracellular iron and significant lipid ROS accumulation. Therefore, our findings provide valuable information that the xCT inhibitor might be a promising therapeutic target for drug-resistant OCCC. The strategy of combined administration of PTX and SAS can potentially be used to treat OCCC and help to develop novel therapeutic methods.

Crosstalk between ferroptosis and steroid hormone signaling in gynecologic cancers

Ferroptosis is a novel types of regulated cell death and is widely studied in cancers and many other diseases in recent years. It is characterized by iron accumulation and intense lipid peroxidation that ultimately inducing oxidative damage. So far, signaling pathways related to ferroptosis are involved in all aspects of determining cell fate, including oxidative phosphorylation, metal-ion transport, energy metabolism and cholesterol synthesis progress, et al. Recently, accumulated studies have demonstrated that ferroptosis is associated with gynecological oncology related to steroid hormone signaling. This review trends to summarize the mechanisms and applications of ferroptosis in cancers related to estrogen and progesterone, which is expected to provide a theoretical basis for the prevention and treatment of gynecologic cancers.

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.

Current Understanding of and Future Directions for Endometriosis-Related Infertility Research with a Focus on Ferroptosis

BACKGROUND

To date, the development of therapy for endometriosis and disease-related infertility remains a major challenge. Iron overload caused by periodic bleeding is a hallmark of endometriosis. Ferroptosis is an iron- and lipid-reactive oxygen species-dependent type of programmed cell death that is distinct from apoptosis, necrosis, and autophagy. This review summarizes the current understanding of and future directions for the research and treatment of endometriosis and disease-related infertility, with the main focus on the molecular basis of ferroptosis in endometriotic and granulosa cells.

METHODS

Papers published between 2000 and 2022 in the PubMed and Google Scholar databases were included in this review.

RESULTS

Emerging evidence suggests that ferroptosis is closely linked to the pathophysiology of endometriosis. Endometriotic cells are characterized by ferroptosis resistance, whereas granulosa cells remain highly susceptible to ferroptosis, suggesting that the regulation of ferroptosis is utilized as an interventional target for research into the treatment of endometriosis and disease-related infertility. New therapeutic strategies are urgently needed to efficiently kill endometriotic cells while protecting granulosa cells.

CONCLUSIONS

An analysis of the ferroptosis pathway in in vitro, in vivo, and animal research enhances our understanding of the pathogenesis of this disease. Here, we discuss the role of ferroptosis modulators as a research approach and potential novel treatment for endometriosis and disease-related infertility.

Establishment of a novel model of endometriosis-associated ovarian cancer by transplanting uterine tissue from Arid1a/Pten knockout mice

Although endometriosis is primarily benign, it has been identified as a risk factor for endometriosis-associated ovarian cancer (EAOC). Genetic alterations in ARID1A, PTEN, and PIK3CA have been reported in EAOC; however, an appropriate EAOC animal model has yet to be established. Therefore, the present study aimed to create an EAOC mouse model by transplanting uterine pieces from donor mice, in which Arid1a and/or Pten was conditionally knocked out (KO) in Pax8-expressing endometrial cells by the administration of doxycycline (DOX), onto the ovarian surface or peritoneum of recipient mice. Two weeks after transplantation, gene KO was induced by DOX and endometriotic lesions were thereafter removed. The induction of only Arid1a KO did not cause any histological changes in the endometriotic cysts of recipients. In contrast, the induction of only Pten KO evoked a stratified architecture and nuclear atypia in the epithelial lining of all endometriotic cysts, histologically corresponding to atypical endometriosis. The induction of Arid1a; Pten double-KO evoked papillary and cribriform structures with nuclear atypia in the lining of 42 and 50% of peritoneal and ovarian endometriotic cysts, respectively, which were histologically similar to EAOC. These results indicate that this mouse model is useful for investigating the mechanisms underlying the development of EAOC and the related microenvironment.

Astaxanthin ameliorates inflammation, oxidative stress, and reproductive outcomes in endometriosis patients undergoing assisted reproduction: A randomized, triple-blind placebo-controlled clinical trial

Purpose

In a randomized, triple-blind, placebo-controlled clinical trial (RCT) including 50 infertile women with endometriosis candidate for assisted reproductive techniques (ART), we studied the effect of Astaxanthin (AST) on pro-inflammatory cytokines, oxidative stress (OS) markers, and early pregnancy outcomes.

Methods

Before and after 12 weeks of AST treatment (6 mg per day), blood serum and follicular fluid (FF) samples were collected from 50 infertile women with endometriosis stage III/IV undergoing ART. Pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and OS markers (malondialdehyde [MDA], superoxide dismutase [SOD], catalase [CAT], and total antioxidant capacity [TAC]) were measured in the serum and FF. ART outcomes were also compared between the groups.

Results

Increased serum levels of TAC (398.661 ± 57.686 vs. 364.746 ± 51.569; P = 0.004) and SOD (13.458 ± 7.276 vs. 9.040 ± 5.155; P = 0.010) were observed after AST therapy in the treatment group. Furthermore, serum MDA (14.619 ± 2.505 vs. 15.939 ± 1.512; P = 0.031) decreased significantly following antioxidant treatment. In addition, significantly lower serum levels of IL-1β (4.515 ± 0.907 vs. 6.8760 ± 0.8478; P = 0.000), IL-6 (5.516 ± 0.646 vs. 5.0543 ± 0.709; P = 0.024) and TNF-α (2.520 ± 0.525 vs. 2.968 ± 0.548; P = 0.038) were observed after AST treatment. In addition, AST supplementation led to an improved number of oocytes retrieved (14.60 ± 7.79 vs. 9.84 ± 6.44; P = 0.043), number of mature (MII) oocytes (10.48 ± 6.665 vs. 6.72 ± 4.3; P = 0.041), and high-quality embryos (4.52 ± 2.41 vs. 2.72 ± 2.40; P = 0.024).

Conclusion

AST pretreatment can modulate inflammation and OS in endometriosis-induced infertile patients. ART outcomes also improved after 12 weeks of AST therapy. Our results suggest that AST can be a potential therapeutic target for infertile patients with endometriosis undergoing ART.

Biomarkers of oxidative stress and reproductive complications

Oxidative stress is the result of an imbalance between the formation of reactive oxygen species (ROS) and the levels of enzymatic and non-enzymatic antioxidants. The assessment of biological redox status is performed by the use of oxidative stress biomarkers. An oxidative stress biomarker is defined as any physical structure or process or chemical compound that can be assessed in a living being (in vivo) or in solid or fluid parts thereof (in vitro), the determination of which is a reproducible and reliable indicator of oxidative stress. The use of oxidative stress biomarkers allows early identification of the risk of developing diseases associated with this process and also opens up possibilities for new treatments. At the end of the last century, interest in oxidative stress biomarkers began to grow, due to evidence of the association between the generation of free radicals and various pathologies. Up to now, a significant number of studies have been carried out to identify and apply different oxidative stress biomarkers in clinical practice. Among the most important oxidative stress biomarkers, it can be mentioned the products of oxidative modifications of lipids, proteins, nucleic acids, and uric acid as well as the measurement of the total antioxidant capacity of fluids in the human body. In this review, we aim to present recent advances and current knowledge on the main biomarkers of oxidative stress, including the discovery of new biomarkers, with emphasis on the various reproductive complications associated with variations in oxidative stress levels.

Ferroptosis As Ultimate Target of Cancer Therapy

Significance: The significance of ferroptosis in cancer therapeutics has now been unveiled. Specific ferroptosis inducers are expected as a promising strategy for cancer treatment, especially in cancers with epithelial mesenchymal transition and possibly in cancers with activated Hippo signaling pathways, both of which cause resistance to traditional chemotherapy but tend to show ferroptosis susceptibility. Recent Advances: Ferroptosis is a new form of regulated non-apoptotic cell death, which is characterized by iron-dependent lipid peroxidation, leading eventually to plasma membrane rupture. Its core mechanisms have been elucidated, consisting of a driving force as catalytic Fe(II)-dependent Fenton reaction and an incorporation of polyunsaturated fatty acids to membrane phospholipids via peroxisome-dependent and -independent pathways, and suppressing factors as prevention of lipid peroxidation with glutathione peroxidase 4 and direct membrane repair via coenzyme Q10 and ESCRT-III pathways. Critical Issues: Developments of ferroptosis inducers are in progress by nanotechnology-based drugs or by innovative engineering devices. Especially, low-temperature (non-thermal) plasma is a novel technology at the preclinical stage. The exposure can induce ferroptosis selectively in cancer cells rich in catalytic Fe(II). Future Directions: We also summarize and discuss the recently uncovered responsible molecular mechanisms in association with iron metabolism, ferroptosis and cancer therapeutics. Targeting ferroptosis in addition to the current therapeutic modalities would be important to cure advanced-stage cancer.

Iron overload modulates follicular microenvironment via ROS/HIF-1α/FSHR signaling

Iron is essential for the health of reproductive system, and women with iron overload suffer from ovarian dysfunction and lack effective treatment in fertility preservation. However, the underlying mechanism of the detrimental effects of iron overload on ovarian function remains ambiguous. Here, we confirmed the excess iron in the circumjacent follicle near endometriomas, which negatively impacted the oocyte development in the affected ovaries. Further, by integrating cell line and chronic iron overload mice model, we demonstrated that iron overload can function as a ROS inducer to amplify mitochondria damage, which significantly elevated the release of cytochrome C and ultimately induced the apoptosis of granular cells. Besides, for the first time, our findings revealed that disruption of HIF-1α/FSHR/CYP19A1 signaling was critical for decreased estrogen synthesis of granular cells in response to iron overload, which can lead to apparent oocyte maldevelopment and subfertility. Overall. this study uncovered that iron overload modulated the follicular microenvironment and generated a deleterious effect on female infertility via ROS/HIF-1α/FSHR signaling. These results might provide potential implications for future clinical risk management of patients with endometrioma and hemopathy.

Environmental impact on carcinogenesis under BRCA1 haploinsufficiency

Cancer is the primary cause of human mortality in Japan since 1981. Although numerous novel therapies have been developed and applied in clinics, the number of deaths from cancer is still increasing worldwide. It is time to consider the strategy of cancer prevention more seriously. Here we propose a hypothesis that cancer can be side effects of long time-use of iron and oxygen and that carcinogenesis is an evolution-like cellular events to obtain "iron addiction with ferroptosis-resistance" where genes and environment interact each other. Among the recognized genetic risk factors for carcinogenesis, we here focus on BRCA1 tumor suppressor gene and how environmental factors, including daily life exposure and diets, may impact toward carcinogenesis under BRCA1 haploinsufficiency. Although mice models of BRCA1 mutants have not been successful for decades in generating phenotype mimicking the human counterparts, a rat model of BRCA1 mutant was recently established that reasonably mimics the human phenotype. Two distinct categories of oxidative stress, one by radiation and one by iron-catalyzed Fenton reaction, promoted carcinogenesis in Brca1 rat mutants. Furthermore, mitochondrial damage followed by alteration of iron metabolism finally resulted in ferroptosis-resistance of target cells in carcinogenesis. These suggest a possibility that cancer prevention by active pharmacological intervention may be possible for BRCA1 mutants to increase the quality of their life rather than preventive mastectomy and/or oophorectomy.

Combined histological and DNA methylome profiling approaches may provide insights into the pathophysiology of ovarian endometriomas

Purpose

To test the theory that invaginated ovarian surface epithelium and endometrial implants on the ovary form ovarian endometriomas.

Methods

Adhesion sites of ovarian endometrioma on the peritoneum and consecutive ovarian endometrioma cyst wall, called non-adhesion sites, were histologically examined. DNA methylomes of the adhesion sites, non-adhesion sites, and blueberry spots were compared with those of ovary, endometrium, and peritoneum.

Results

The non-adhesion sites showed an ovarian surface epithelium-like structure near the adhesion site, which continued to a columnar epithelium-like structure. Calretinin staining was strong in the ovarian surface epithelium-like structure but weak in the columnar epithelium-like structure. Estrogen receptors were absent in the ovarian surface epithelium-like structure, but present in the columnar epithelium-like structure. The adhesion sites had endometrial gland-like structures that expressed estrogen receptors. Analyses of DNA methylomes classified the non-adhesion sites and ovaries into the same group, suggesting that ovarian endometriomas originate from the ovarian surface epithelium. The adhesion sites, blueberry spots and peritoneum were classified in the same group, suggesting that the adhesion sites and blueberry spots originate from the peritoneum.

Conclusions

The present results support the invagination theory. Ovarian endometriomas consist of invaginated ovarian surface epithelium with celomic metaplasia and endometrium implants on the peritoneum.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Hereditary hemochromatosis: Temporal trends, sociodemographic characteristics, and independent risk factor of hepatocellular cancer – nationwide population-based study

BACKGROUND

Hereditary hemochromatosis (HH) has an increased risk of hepatocellular cancer (HCC) both due to genetic risks and iron overload as iron overload can be carcinogenic; HH impacts the increasing risk of HCC, not only through the development of cirrhosis but concerning hepatic iron deposition, which has been studied further recently.

AIM

To evaluate HH yearly trends, patient demographics, symptoms, comorbidities, and hospital outcomes. The secondary aim sheds light on the risk of iron overload for developing HCC in HH patients, independent of liver cirrhosis complications. The study investigated HH (without cirrhosis) as an independent risk factor for HCC.

METHODS

We analyzed data from National Inpatient Sample (NIS) Database, the largest national inpatient data collection in the United States, and selected HH and HCC cohorts. HH was first defined in 2011 International Classification of Disease - 9^th edition (ICD-9) as a separate diagnosis; the HH cohort is extracted from January 2011 to December 2019 using 275.01 (ICD-9) and E83.110 (ICD-10) diagnosis codes of HH. Patients were excluded from the HH cohort if they had a primary or secondary diagnostic code of cirrhosis (alcoholic, non-alcoholic, and biliary), viral hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD), and non-alcoholic steatohepatitis (NASH). We removed these patients from the HH cohort to rule out bias or ICD-10 diagnostic errors. The HCC cohort is selected from January 2011 to December 2019 using the ICD-9 and ICD-10 codes of HCC. We selected a non-HCC cohort with the 1:1 fixed ratio nearest neighbor (greedy) propensity score method using the patients' age, gender, and race. We performed multivariate analysis for the risk factors of HCC in the HCC and non-HCC matched cohort. We further analyzed HH without cirrhosis (removing HH patients with a diagnosis of cirrhosis) as an independent risk factor of HCC after adjusting all known risk factors of HCC in the multivariate model.

RESULTS

During the 2011-2019 period, a total of 18031 hospitalizations with a primary or secondary diagnosis of HH (excluding liver diseases) were recorded in the NIS database. We analyzed different patients’ characteristics, and we found increments in inpatient population trend with a Ptrend < 0.001 and total hospital cost of care trend from $42957 in 2011 to $66152 in 2019 with a Ptrend < 0.001 despite no change in Length of Stay over the last decade. The multivariate analyses showed that HH without cirrhosis (aOR, 28.8; 95%CI, 10.4–80.1; P < 0.0001), biliary cirrhosis (aOR, 19.3; 95%CI, 13.4–27.6; P < 0.0001), non-alcoholic cirrhosis (aOR, 17.4; 95%CI, 16.5–18.4; P < 0.0001), alcoholic cirrhosis (aOR, 16.9; 95%CI, 15.9–17.9; P < 0.0001), hepatitis B (aOR, 12.1; 95%CI, 10.85–13.60; P < 0.0001), hepatitis C (aOR, 8.58; 95%CI, 8.20–8.98; P < 0.0001), Wilson disease (aOR, 4.27; 95%CI, 1.18–15.41; P < 0.0001), NAFLD or NASH (aOR, 2.96; 95%CI, 2.73–3.20; P < 0.0001), alpha1-antitrypsin deficiency (aOR, 2.10; 95%CI, 1.21–3.64; P < 0.0001), diabetes mellitus without chronic complications (aOR, 1.17; 95%CI, 1.13–1.21; P < 0.0001), and blood transfusion (aOR, 1.80; 95%CI, 1.69–1.92; P < 0.0001) are independent risk factor for liver cancer.

CONCLUSION

Our study showed an increasing trend of in-hospital admissions of HH patients in the last decade. These trends were likely related to advances in diagnostic approach, which can lead to increased hospital utilization and cost increments. Still, the length of stay remained the same, likely due to a big part of management being done in outpatient settings. Another vital part of our study is the significant result that HH without cirrhosis is an independent risk factor for HCC with adjusting all known risk factors. More prospective and retrospective large studies are needed to re-evaluate the HH independent risk in developing HCC.

The presence of living endometrial cells in ovarian endometriotic cyst fluid may contribute to the recurrence of endometriosis after surgical excision of endometriomas

BACKGROUND

Many factors can affect the recurrence of endometriosis after surgery, however, whether endometriotic cyst fluid contributes to endometriosis recurrence after surgical excision of ovarian endometriomas remains unclear. The objective of this study was to determine the presence of endometrial cells in ovarian endometriosis cyst fluid and the potential differences between these cells and those in the cyst wall.

METHODS

Samples of cyst fluid (n = 39) and drainage fluid (n = 14) were collected from patients with ovarian endometriomas undergoing laparoscopic surgery. Drainage fluid from 14 patients without endometriosis was used as a control. The presence of endometrial cells in cyst fluid and drainage fluid was determined by cell culture in vitro and immunostaining. In addition, cyst fluid endometrial fragments and viscosity were analysed by transcriptome sequencing analysis and apparent diffusion coefficients, respectively. An animal model was used to confirm the ability of endometrial cells in cyst fluid to form new lesions.

RESULTS

We found endometrium-like tissues in 71.8% (28/39) of cyst fluid and 71.4% (10/14) of drainage fluid samples by histopathological examination, and the presence of endometrioid tissue in cyst fluid was related to the viscosity of the cyst fluid. The living endometrial cells in cyst fluid and drainage fluid were confirmed by cell culture in vitro and immunostaining. Moreover, the adhesion ability of endometrial fragments in cyst fluid was significantly higher than that of ectopic tissues in the cyst wall (P < 0.05). In addition, living endometrial cells in the cyst fluid were able to adhere and alive in the animal model.

CONCLUSIONS

The existence of living endometrial cells with high adhesion ability in ovarian endometriotic cyst fluid may contribute to the recurrence of endometriosis after surgical excision of endometriomas due to cyst fluid outflow during the surgical procedure.

Cancer-inducing niche: the force of chronic inflammation

The growth of cancer tissue is thought to be considered driven by a small subpopulation of cells, so-called cancer stem cells (CSCs). CSCs are located at the apex of a hierarchy in a cancer tissue with self-renewal, differentiation and tumorigenic potential that produce the progeny in the tissue. Although CSCs are generally believed to play a critical role in the growth, metastasis, and recurrence of cancers, the origin of CSCs remains to be reconsidered. We hypothesise that, chronic diseases, including obesity and diabetes, establish the cancer-inducing niche (CIN) that drives the undifferentiated/progenitor cells into CSCs, which then develop malignant tumours in vivo. In this context, a CIN could be traced to chronic inflammation that involves long-lasting tissue damage and repair after being exposed to factors such as cytokines and growth factors. This must be distinguished from the cancer microenvironment, which is responsible for cancer maintenance. The concept of a CIN is most important for cancer prevention as well as cancer therapy.

Integrative genomic and transcriptomic analysis reveals immune subtypes and prognostic markers in ovarian clear cell carcinoma

BACKGROUND

We performed an integrative genomic and transcriptomic profiling to identify molecular subtypes and prognostic markers with special focus on immune-related pathways.

METHODS

Totally, 50 Chinese patients were subjected to targeted next-generation sequencing and transcriptomic sequencing.

RESULTS

Two distinct subgroups were identified as immune (22.0%) and non-immune (78.0%) based on the immune-pathway related hierarchical clustering. Surprisingly, patients with immune subtype had a significantly worse survival. The prognostic capacity was validated in external cohorts. The immune group had higher expression of genes involved in pro-inflammation and checkpoints. PD-1 signalling pathway was enriched in the immune subtype. Besides, the immune cluster presented enriched expression of genes involved in epithelial-mesenchymal transition, angiogenesis and PI3K-AKT-mTOR signalling, while the non-immune subtype had higher expression of metabolic pathways. The immune subtype had a higher mutation rate of PIK3CA though significance was not achieved. Lastly, we established a prognostic immune signature for overall survival. Interestingly, the immune signature could also be applied to renal clear cell carcinoma, but not to other histologic subtype of ovarian cancer.

CONCLUSIONS

An immune subtype of OCCC was identified with poor survival and enrichment of PD-1 and PI3K-AKT-mTOR signalling. We constructed and validated a robust prognostic immune signature of OCCC patients.

Does current ovarian endometrioma increase the time for DOR patients to reach live birth in IVF?

BACKGROUND

The contents of ovarian endometrioma (OMA) such as inflammatory mediators, reactive oxygen species, and iron may disrupt normal folliculogenesis and result in subsequent oocyte apoptosis. Therefore, women with OMA have a potential risk of diminished ovarian reserve (DOR). The purpose of this study is to compare the in vitro fertilization (IVF) outcomes and efficiency between DOR patients with and without current OMA.

METHODS

This retrospective case-control study included a total of 493 women with DOR (serum anti-Müllerian hormone level < 1.1 ng/mL). Ninety patients with OMA (Group A) underwent 191 IVF cycles and 403 patients without ovarian OMA (Group B) underwent 888 IVF cycles in our center between January 2014 and December 2018. Basal characteristics and IVF outcomes were compared between Group A and Group B. Time to achieve live birth were compared between patients with live birth in two groups (Group A1, 31 patients; Group B1, 132 patients).

RESULTS

Clinical and demographic characteristics of patients were similar respectively between groups (A vs. B, A1 vs. B1). There were no statistically significant differences in implantation rate, live birth rate per OPU and per ET cycle and the cumulative live birth rate per patient and per patient with good-quality embryos between Group A and Group B (P > 0.05). Total time to achieve live birth has no statistically significant difference between Group A1 and Group B1 (P > 0.05).

CONCLUSION

For DOR women, presence of endometrioma did not affect the IVF outcomes. Even the time to get live birth was not prolonged by current OMA.

Endometrial stromal cell ferroptosis promotes angiogenesis in endometriosis

Endometriosis, a chronic disorder characterised by the presence of endometrial-like tissue outside the uterus, is associated with iron overload and oxidative stress in the lesion. Although it is well established that iron overload can trigger ferroptosis, the results of previous studies on ferroptosis resistance and ferroptosis in endometriotic lesions are paradoxical. Here, we found that some stromal cells of the cyst walls that were in contact with the cyst fluid underwent ferroptosis. Surprisingly, endometrial stromal cell ferroptosis triggered the production of angiogenic, inflammatory and growth cytokines. In particular, angiogenic cytokines, such as vascular endothelial growth factor A (VEGFA) and interleukin 8 (IL8), promoted human umbilical vein endothelial cell (HUVEC) vascular formation in vitro. Moreover, we found that inhibition of p38 mitogen-activated protein kinase/signal transducer and activator of transcription 6 (p38 MAPK/STAT6) signalling represses VEGFA and IL8 expression when endometrial stromal cells undergo ferroptosis. Notably, VEGFA and IL8 showed localised expression and were significantly upregulated in ectopic lesions compared to control and eutopic endometrium samples from patients with endometriosis. Thus, our study reveals that endometrial stromal cell ferroptosis in the ovarian endometrioma may trigger cytokine secretion and promote angiogenesis of adjacent lesions via paracrine actions to drive the development of endometriosis, providing a rationale for translation into clinical practice and developing drugs for endometriosis.

Iron overload inhibits cell proliferation and promotes autophagy via PARP1/SIRT1 signaling in endometriosis and adenomyosis

Emerging evidence suggests that excess iron accumulates in endometriotic and adenomyotic lesions. However, the role iron overload plays in the pathogenesis of endometriosis or adenomyosis remains unknown. Primary human eutopic endometrial stromal cells (EuESCs) from endometriosis or adenomyosis patients were used as the in vitro model of endometriosis or adenomyosis in this study. We found that iron, manifesting as ferric ammonium citrate (FAC; 0.05-4.8 mM), significantly inhibited cell growth, induced oxidative stress through the Fenton reaction, and functionally activated autophagy in EuESCs, as measured by 5-ethynyl-2'-deoxyuridine incorporation assay, MitoSOX™ Red staining, LC3 turnover assay, and tandem mCherry-eGFP-LC3B fluorescence microscopy. Immunohistochemistry analysis of Ki67 expression in proliferative-phase endometrial tissues revealed that cell proliferation in ectopic tissues was dramatically compromised, suggesting that iron overload may play a role in cell growth inhibition in vivo. We observed that autophagy may alleviate the FAC-induced inhibition of endometrial stromal cell proliferation. Furthermore, sequential FAC (0.8 mM, 24 h) and hydrogen peroxide (H₂O₂; 300 μM, 2 h) treatment successfully induced the Fenton reaction in EuESCs and caused extensive apoptosis, whereas the disruption of autophagy by the knockdown of BECN1 further aggravated cell death. MitoSOX™ Red staining showed that autophagy may promote the survival of EuESCs by decreasing of the Fenton reaction-induced reactive oxygen species generation. In addition, we observed that the Fenton reaction-induced oxidative stress significantly suppressed iron overload-induced autophagy. Moreover, we found that FAC treatment impaired poly(ADP-ribose)-polymerase 1 (PARP1) expression while simultaneously upregulating SIRT1 expression in EuESCs. Our data further showed that PARP1 expression decreased in endometriotic lesions, which may partially result from iron overload. We also found that PARP1 inhibition aggravated iron overload-induced cell growth suppression, and was implicated in iron overload-induced autophagy. In addition, SIRT1 silencing alleviated iron overload-induced PARP1 downregulation and autophagy activation. Overall, our data suggest that iron overload in endometrial stromal cells of endometriotic or adenomyotic lesions may be involved in the inhibition of cell proliferation, simultaneously with the activation of protective autophagy via PARP1/SIRT1 signaling.

APOBEC mediated mutagenesis drives genomic heterogeneity in endometriosis

Endometriosis is a benign gynecologic condition, acting as a precursor of certain histological subtypes of ovarian cancers. The epithelial cells of endometriotic tissues and normal uterine endometrium accumulated somatic mutations in cancer-associated genes such as phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and Kirsten rat sarcoma (KRAS) proto-oncogene. To determine the genomic characteristic of endometriotic epithelial cells and normal uterine endometrium and to identify the predominant mutational process acting on them, we studied the somatic mutation profiles obtained from whole exome sequencing of 14 endometriotic epithelium and 11 normal uterine endometrium tissues and classified them into mutational signatures. We observed that single base substitutions 2/13 (SBS), attributed to Apolipoprotein B mRNA Editing Enzyme Catalytic Subunit (APOBEC) induced mutagenesis, were significant in endometriotic tissues, but not in the normal uterine endometrium. Additionally, the larger number and wider allele frequency distribution of APOBEC signature mutations, compared to cancer-associated driver mutations in endometriotic epithelium suggested APOBEC mutagenesis as an important source of mutational burden and heterogeneity in endometriosis. Further, the relative risk of enriched APOBEC signature mutations was higher in endometriosis patients who were carriers of APOBEC3A/3B germline deletion, a common polymorphism in East Asians which involves the complete loss of APOBEC3B coding region. Our results illustrate the significance of APOBEC induced mutagenesis in driving the genomic heterogeneity of endometriosis.

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.

MRI in the Diagnosis of Endometriosis and Related Diseases

Endometriosis, a common chronic inflammatory disease in female of reproductive age, is closely related to patient symptoms and fertility. Because of its high contrast resolution and objectivity, MRI can contribute to the early and accurate diagnosis of ovarian endometriotic cysts and deeply infiltrating endometriosis without the need for any invasive procedure or radiation exposure. The ovaries, which are the most frequent site of endometriosis, can be afflicted by multiple related conditions and diseases. For the diagnosis of deeply infiltrating endometriosis and secondary adhesions among pelvic organs, fibrosis around the ectopic endometrial gland is usually found as a T2 hypointense lesion. This review summarizes the MRI findings obtained for ovarian endometriotic cysts and their physiologically and pathologically related conditions. This article also includes the key imaging findings of deeply infiltrating endometriosis.

Nanomedicine Targets Iron Metabolism for Cancer Therapy

Iron is an essential element for cell proliferation and homeostasis by engaging in cell metabolism including DNA synthesis, cell cycle, and redox cycling; however, iron overload could contribute to tumor initiation, proliferation, metastasis, and angiogenesis. Therefore, manipulating iron metabolisms, such as using iron chelators, transferrin receptor 1 (TFR1) Abs, and cytotoxic ligands conjugated to transferrin, has become a considerable strategy for cancer therapy. However, there remain major limitations for potential translation to the clinic based on the regulation of iron metabolism in cancer treatment. Nanotechnology has made great advances for cancer treatment by improving the therapeutic potential and lowering the side‐effects of the proved drugs and those under various stages of development. Early studies that combined nanotechnology with therapeutic means for the regulation of iron metabolism have shown certain promise for developing specific treatment options based on the intervention of cancer iron acquisition, transportation, and utilization. In this review, we summarize the current understanding of iron metabolism involved in cancer and review the recent advances in iron‐regulatory nanotherapeutics for improved cancer therapy. We also envision the future development of nanotherapeutics for improved treatment for certain types of cancers.

Endometriosis-associated Ovarian Clear Cell Carcinoma: A Special Entity?

Endometriosis is an estrogen-dependent disease, which serves as a precursor of ovarian cancer, especially clear cell carcinoma (OCCC) and endometrial carcinoma. Although micro-environmental factors such as oxidative stress, immune cell dysfunction, inflammation, steroid hormones, and stem cells required for malignant transformation have been found in endometriosis, the exact carcinogenic mechanism remains unclear. Recent research suggest that many putative driver genes and aberrant pathways including ARID1A mutations, PIK3CA mutations, MET activation, HNF-1β activation, and miRNAs dysfunction, play crucial roles in the malignant transformation of endometriosis to OCCC. The clinical features of OCCC are different from other histological types. Patients usually present with a large, unilateral pelvic mass, and occasionally have thromboembolic vascular complications. OCCC patients are easier to be resistant to chemotherapy, have a worse prognosis, and are usually difficult to treat. To improve the survival of OCCC patients, it is necessary to better understand its specific carcinogenic mechanism and explore new treatment strategy, including molecular target.

PDK2 leads to cisplatin resistance through suppression of mitochondrial function in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (CCC) exhibits an association with endometriosis, resistance to oxidative stress, and poor prognosis owing to its resistance to conventional platinum‐based chemotherapy. A greater understanding of the molecular characteristics and pathogenesis of ovarian cancer subtypes may facilitate the development of targeted therapeutic strategies, although the mechanism of drug resistance in ovarian CCC has yet to be determined. In this study, we assessed exome sequencing data to identify new therapeutic targets of mitochondrial function in ovarian CCC because of the central role of mitochondria in redox homeostasis. Copy number analyses revealed that chromosome 17q21‐24 (chr.17q21‐24) amplification was associated with recurrence in ovarian CCC. Cell viability assays identified an association between cisplatin resistance and chr.17q21‐24 amplification, and mitochondrion‐related genes were enriched in patients with chr.17q21‐24 amplification. Patients with high expression of pyruvate dehydrogenase kinase 2 (PDK2) had a worse prognosis than those with low PDK2 expression. Furthermore, inhibition of PDK2 synergistically enhanced cisplatin sensitivity by activating the electron transport chain and by increasing the production of mitochondrial reactive oxygen species. Mouse xenograft models showed that inhibition of PDK2 with cisplatin inhibited tumor growth. This evidence suggests that targeting mitochondrial metabolism and redox homeostasis is an attractive therapeutic strategy for improving drug sensitivity in ovarian CCC.

Malignancies Associated with Extraovarian Endometriosis: A Literature Review

Endometriosis-associated ovarian malignancies have been well documented. Although these malignancies also occur as extraovarian lesions, little is known about them. Thus, this literature review aimed to further explore these rarely experienced tumors. A total of 257 published cases between April 1990 and April 2020 were found using PubMed, and 212 cases were included in the analysis considering Sampson’s criteria and the history of endometriosis. We classified these cases as follows: intestine, abdominal scar, vagina and vulva, peritoneum and deep endometriosis, urinary tract, uterine cervix, and others. Age of patients, history of endometriosis, types of past hormonal therapy, symptoms, histological types, and treatment were identified. The most common tumor site was the intestine. Endometrioid carcinoma was the dominant histological type. Contrary to the ovary, clear cell carcinoma was rare in extraovarian sites. On the other hand, clear cell carcinoma represented the largest number of abdominal scars. This difference may help us to understand the development of endometriosis-related malignancies. Hormonal treatment was mentioned in 67 cases and estrogen replacement therapy in 33 cases. Although risks of estrogen therapy are still controversial, the highly differentiated histological types and hormone-dependent characteristics of endometriosis-associated malignancy should be considered. Physicians should be careful about estrogen monotherapy after hysterectomy and long-term hormone replacement therapy in patients with a history of endometriosis.

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.

Immunochemical analysis of iron transporters and M2 macrophages in ovarian endometrioma and clear cell adenocarcinoma

The association between iron ions and endometriosis-associated ovarian cancer (EAOC) has been previously investigated to elucidate EAOC carcinogenesis; however, the dynamics of iron deposition in the endometrial epithelium and endometrial stroma of ovarian endometrioma (OE) remains unknown. The present study aimed to determine the expression of iron transporters on the cell surface and the distribution of tumor-associated macrophages (TAMs) englobed with iron in the endometrial stroma. The current retrospective study investigated 20 OE and 18 ovarian clear cell adenocarcinoma (CCC) samples, using Perls Prussian blue staining and immunohistochemistry of iron transporters, including divalent metal transporter 1 (DMT1), transferrin receptor (TfR) and ferroportin (FPN). Additionally, samples were stained for CD68, CD11c, CD163 and CD206, and double-immunostained for iron and CD163 to define the distribution of macrophages. Iron transporters were identified on the endometrial epithelium of OE and CCC tumor cells, and TAMs were englobed with iron in the endometrial stroma of OE and CCC. Histological findings revealed DMT1 upregulation in OE and CCC, whereas lower TfR and FPN expression was observed in OE than in CCC. M2 macrophages were englobed with iron ions in the deep layers of the OE and CCC stroma. The endometrial epithelium located in the endometrial stroma of one patient with OE and the endometrial epithelium adjacent to CCC in two patients with CCC stained positive for the tumor proliferation marker Ki67. Epithelium infiltrating the stroma of OE may become the origin of cancer under the influence of M2 macrophages englobed with iron. These findings provide new perspectives on the malignant transformation of OE into EAOC and its possibility as a precancerous index.

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.

Endometrial DNA damage response is modulated in endometriosis

STUDY QUESTION

Is the DNA damage response (DDR) dysregulated in the eutopic endometrium of women with endometriosis?

SUMMARY ANSWER

Endometrial expression of genes involved in DDR is modulated in women with endometriosis, compared to those without the disease.

WHAT IS KNOWN ALREADY

Ectopic endometriotic lesions are reported to harbour somatic mutations, thereby hinting at dysregulation of DDR and DNA repair pathways. However, it remains inconclusive whether the eutopic endometrium also manifests dysregulated DDR in endometriosis.

STUDY DESIGN, SIZE, DURATION

For this case-control study conducted between 2015 and 2019, eutopic endometrial (E) samples (EE- from women with endometriosis, CE- from women without endometriosis) were collected in either mid-proliferative (EE-MP, n = 23; CE-MP, n = 17) or mid-secretory (EE-MS, n = 17; CE-MS, n = 9) phases of the menstrual cycle. This study compares: (i) DNA damage marker localization, (ii) expression of DDR genes and (iii) expression of DNA repair genes in eutopic endometrial samples from women with and without endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included (i) 40 women (aged 31.9 ± 0.81 years) with endometriosis and (ii) 26 control women (aged 31.4 ± 1.02 years) without endometriosis. Eutopic endometrial samples from the two groups were divided into different parts for histological analysis, immunohistochemistry, RNA extraction, protein extraction and comet assays. Eighty-four genes of relevance in the DNA damage signalling pathway were evaluated for their expression in eutopic endometrial samples, using RT2 Profiler PCR arrays. Validations of the expression of two GADD (Growth Arrest DNA Damage Inducible) proteins - GADD45A and GADD45G were carried out by immunoblotting. DNA damage was assessed by immunohistochemical localization of γ-H2AFX (a phosphorylated variant of histone H2AX) and 8-OHdG (8-hydroxy-2'-deoxyguanosine). RNA sequencing data from mid-proliferative (EE-MP, n = 4; CE-MP, n = 3) and mid-secretory phase (EE-MS and CE-MS, n = 4 each) endometrial samples were scanned to compare the expression status of all the genes implicated in human DNA repair. PCNA (Proliferating Cell Nuclear Antigen) expression was determined to assess endometrial proliferation. Residual DNA damage in primary endometrial cells was checked by comet assays. Public datasets were also scanned for the expression of DDR and DNA repair genes as our RNASeq data were limited by small sample size. All the comparisons were made between phase-matched endometrial samples from women with and without endometriosis.

MAIN RESULTS AND THE ROLE OF CHANCE

Endometrial expression of DDR genes and intensity of immunolocalized γ-H2AFX were significantly (P < 0.05) higher in EE, compared to CE samples. DDR proteins, especially those belonging to the GADD family, were found to be differentially abundant in EE, as compared to CE. These patterns were evident in both mid-proliferative and mid-secretory phases. Intriguingly, higher DDR was associated with increased cell proliferation in EE-MP, compared to CE-MP. Furthermore, among the differentially expressed transcripts (DETs) encoded by DNA repair genes, the majority showed up-regulation in EE-MP, compared to CE-MP. Interestingly, CE-MP and EE-MP had a comparable percentage (P > 0.05) of cells with residual DNA damage. However, unlike the mid-proliferative phase data, many DETs encoded by DNA repair genes were down-regulated in EE-MS, compared to CE-MS. An analysis of the phase-matched control and endometriosis samples included in the GSE51981 dataset available in the Gene Expression Omnibus database also revealed significant (P < 0.05) alterations in the expression of DDR and DNA repair genes in EE, compared to CE.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The study was conducted on a limited number of endometrial samples. Also, the study does not reveal the causes underlying dysregulated DDR in the eutopic endometrium of women with endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Alterations in the expression of DDR and DNA repair genes indirectly suggest that eutopic endometrium, as compared to its healthy counterpart, encounters DNA damage-inducing stimuli, either of higher strength or for longer duration in endometriosis. It will be worthwhile to identify the nature of such stimuli and also explore the role of higher genomic insults and dysregulated DDR/DNA repair in the origin and/or progression of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the Department of Biotechnology and Indian Council of Medical Research, Government of India. No conflict of interest is declared.

Acquired Evolution of Mitochondrial Metabolism Regulated by HNF1B in Ovarian Clear Cell Carcinoma

Clear cell carcinoma (CCC) of the ovary exhibits a unique morphology and clinically malignant behavior. The eosinophilic cytoplasm includes abundant glycogen. Although the growth is slow, the prognosis is poor owing to resistance to conventional chemotherapies. CCC often arises in endometriotic cysts and is accompanied by endometriosis. Based on these characteristics, three clinical questions are considered: why does ovarian cancer, especially CCC and endometrioid carcinoma, frequently occur in endometriotic cysts, why do distinct histological subtypes (CCC and endometrioid carcinoma) arise in the endometriotic cyst, and why does ovarian CCC possess unique characteristics? Mutations in AT-rich interacting domain-containing protein 1A and phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit alpha genes may contribute to the carcinogenesis of ovarian CCC, whereas hepatocyte nuclear factor-1-beta (HNF1B) plays crucial roles in sculpting the unique characteristics of ovarian CCC through metabolic alterations. HNF1B increases glutathione synthesis, activates anaerobic glycolysis called the Warburg effect, and suppresses mitochondria. These metabolic changes may be induced in stressful environments. Life has evolved to utilize and control energy; eukaryotes require mitochondria to transform oxygen reduction into useful energy. Because mitochondrial function is suppressed in ovarian CCC, these cancer cells probably acquired further metabolic evolution during the carcinogenic process in order to survive stressful environments.

A delicate redox balance between iron and heme oxygenase-1 as an essential biological feature of endometriosis

BACKGROUND

Recent studies have focused on the role of oxidative stress, which may be implicated in the development, progression, and pathophysiology of endometriosis.

AIM OF THE STUDY

The aim of this study is to investigate the redox balance of endometriosis by simultaneously measuring iron-related compounds (total iron, heme iron, free iron, oxyhemoglobin [oxyHb], methemoglobin [metHb] and 8-hydroxy-2-deoxy guanosine [8-OHdG]) and antioxidants (bilirubin, heme oxygenase-1 [HO-1] and total antioxidant capacity [TAC]).

METHODS

This study includes 236 histopathologically confirmed cases (178 cases of endometriosis and 58 cases of non-endometriosis). Cyst fluid samples were collected from patients admitted to the Department of Gynecology, Nara Medical University, Kashihara, Japan, for surgery.

RESULTS

Age at diagnosis (p <0.001), the maximum diameter of the cyst (p <0.001) and CA125 levels (p <0.001) differed significantly between the two groups. Total iron, heme iron, free iron, metHb, and oxyHb were markedly higher in endometriosis compared to non-endometriosis. Bilirubin, HO-1 and TAC were significantly higher in endometriosis patients compared with those from non-endometriosis patients. In endometriosis, total iron showed a positive correlation with HO-1 (r, 0.518, p = 0.001), but there were no antioxidants that correlated with iron in non-endometriosis. Iron and HO-1 did not correlate with age or tumor size.

CONCLUSIONS

HO-1 may regulate the delicate balance of iron-induced oxidative stress in endometriotic cyst fluid.

Further evidence that endometriosis is related to tubal and ovarian cancers: A study of 271,444 inpatient women

OBJECTIVE

To evaluate associations between endometriosis and tubal and ovarian cancers in a large population-based study.

METHODS

The Health Care Cost and Utilization Project - National Inpatient Sample databases from 2005 to 2014 were used in this study. Data on patients with a diagnosis of tubal or ovarian cancer and endometriosis (overall and subtypes including adenomyosis and pelvic endometriosis) using International Classification of Diseases, Ninth Edition, Clinical Modification codes were extracted. Logistic regression analysis was performed to evaluate associations between tubal and ovarian cancers and endometriosis. Adjustment was made for age, race, median income level, payment plan, hospital location and obesity.

RESULTS

Of 38,800,139 women aged >18 years who were hospitalized between 2005 and 2014, 271,444 women with adenomyosis and/or pelvic endometriosis, 4289 women with tubal cancer and 133,253 women with ovarian cancer were identified. The rate of tubal cancer was three-fold higher in women with endometriosis compared with women without endometriosis (0.03 % vs 0.01 %). The odds ratio (OR) adjusted for age, race, obesity, income and insurance type was 4.02 [95 % confidence interval (CI) 3.17-5.11; p < 0.01]. The rate of tubal cancer was higher in women with adenomyosis (0.04 % vs 0.01 %; adjusted OR 4.88, 95 % CI 3.66-6.50; p < 0.01) and women with pelvic endometriosis (0.02 % vs 0.01 %; adjusted OR 2.80, 95 % CI 1.84-4.27; p < 0.01) compared with women without these conditions. Similar associations were found between ovarian cancer and pelvic endometriosis and ovarian cancer and adenomyosis.

CONCLUSION

Both pelvic endometriosis and adenomyosis are strongly associated with tubal and ovarian cancers.