Proliferation Of Ectopic Endometrial Cells Research Articles

Endometriosis and autoimmunity.

Endometriosis is a female-specific chronic condition that affects 1 in 10 women and other individuals with a uterus worldwide with common symptoms that include pelvic pain and infertility. Reliable and effective non-invasive biomarkers for endometriosis do not exist, and therefore currently a diagnosis of endometriosis requires direct visualization of lesions at surgery. Similarly, few safe and effective management strategies exist for endometriosis, with hormonal interventions and surgery only providing temporary symptom control. The development of endometriosis involves the implantation and proliferation of ectopic endometrial cells which triggers local and systemic inflammation and fibrosis. While multiple genetic, environmental, and lifestyle factors appear to influence the natural history of endometriosis, chronic inflammation is a hallmark feature associated with development and progression of the disease. Data further shows that endometriosis commonly co-occurs with autoimmune diseases, adding evidence that immune dysfunction likely contributes to the pathogenesis of this disorder. Specific innate and adaptive immune system drivers of endometriosis remain to be identified and additional research is needed to elucidate the mechanistic underpinnings of this debilitating disease. In this narrative review, we discuss the shared biological mechanisms and plausible immune-related connections between endometriosis and autoimmunity.

Controversial Roles of Autophagy in Adenomyosis and Its Implications for Fertility Outcomes-A Systematic Review.

Background/Objectives: Adenomyosis is a benign condition where ectopic endometrial glandular tissue is found within the uterine myometrium. Its impact on women's reproductive outcomes is substantial, primarily due to defective decidualization, impaired endometrial receptivity, and implantation failure. The exact pathogenesis of the disease remains unclear, and the role of autophagy in adenomyosis and its associated infertility is not well understood. The aim of this systematic review was to conduct an exhaustive search of the literature to clarify the role of autophagy in the pathogenesis of adenomyosis. Methods: A systematic search was conducted in Medline, Embase, and Scopus databases up to the date of 20 August 2024. We included all English-written publications assessing the role of autophagy in the pathogenesis of adenomyosis. Results: Seventeen eligible articles were identified, including reviews and experimental studies involving human samples and murine models. The results showed that the role of autophagy in adenomyosis is controversial, with studies showing both increased and decreased levels of autophagy in adenomyosis. Conclusions: Autophagy plays a dual role in cell survival and death. Increased autophagy might support the survival and proliferation of ectopic endometrial cells, while decreased autophagy could prevent cell death, leading to abnormal growth. Oxidative stress may trigger pro-survival autophagy, mitigating apoptosis and promoting cellular homeostasis. Hormonal imbalances disrupt normal autophagic activity, potentially impairing endometrial receptivity and decidualization and contributing to infertility. The balance of autophagy is crucial in adenomyosis, with its dual role contributing to the complexity of the disease. Limitations: A few studies have been conducted with heterogeneous populations, limiting comparative analyses.

PCGEM1 promotes cell proliferation and migration in endometriosis by targeting miR-124-3p-mediated ANTXR2 expression

BackgroundEndometriosis, a common gynaecological disease in women, affects 10% of women of childbearing age. Among infertile women, this proportion is as high as 30–50%. Despite the high prevalence of endometriosis, the pathogenesis of endometriosis is still unclear.MethodsIn the present study, bioinformatics analysis and molecular and animal experiments were employed to explore the functions of PCGEM1 in the pathogenesis of endometriosis. We established an endometriosis rat model and isolated endometrial stromal cells (ESCs) and primary normal ESCs (NESCs). Bioinformatics analysis was adopted to study the roles of PCGEM1 in promoting the pathogenesis of endometriosis. Luciferase reporter assays and RNA pull-down assays were carried out to study the mechanism by which PCGEM1 regulates ANTXR2.ResultsOur results indicated that PCGEM1 promoted the motility and proliferation of ectopic endometrial cells, and the underlying mechanism was due to the direct binding of PCGEM1 to miR-124-3p to modulate ANTXR2 expression.ConclusionPCGEM1 can influence endometrial stromal cell proliferation and motility and may be a novel therapeutic target for endometriosis.

Long non-coding RNA DHRS4 antisense RNA 1 inhibits ectopic endometrial cell proliferation, migration, and invasion in endometriosis by regulating microRNA-139-5p expression

ABSTRACT Endometriosis is an estrogen-dependent chronic gynecological syndrome. Recent studies have shown that long non-coding RNAs participate in the pathogenesis and development of endometriosis. This study aimed to explore the mechanisms of DHRS4 antisense RNA 1 (DHRS4-AS1) in endometriosis. Dual-luciferase reporter assays were conducted to determine the relationship between DHRS4-AS1, microRNA (miR)-139-5p, and arrestin domain-containing 3 (ARRDC3). Furthermore, the expression of DHRS4-AS1 and miR-139-5p in ectopic endometrial stromal cells (EC-ESCs) and endometriosis tissues was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Additionally, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, and Transwell assays were performed to evaluate the proliferation, apoptosis, and migration and invasion of EC-ESCs, respectively. Western blotting and RT-qPCR were further utilized to determine cleaved-Caspase 3, Caspase 3, and matrix metalloproteinase 9 (MMP-9) expression levels. Compared with the EN group, DHRS4-AS1 levels were lower and miR-139-5p levels were higher in EC-ESCs and tissues obtained from patients with endometriosis. Functional assays validated that DHRS4-AS1 targets miR-139-5p, with ARRDC3 being a downstream target of miR-139-5p. Rescue experiments demonstrated that DHRS4-AS1 inhibited EC-ESC proliferation, migration, and invasion, but promoted apoptosis, by targeting miR-139-5p in endometriosis. cleaved-Caspase3 expression level and the cleaved-Caspase 3/Caspase 3 ratio increased, while the expression levels of MMP-9 decreased, after transfection with DHRS4-AS1 overexpression plasmids; however, the effects induced by DHRS4-AS1 overexpression could be partially reversed by co-transfection with the miR-139-5p mimic. The current study demonstrates that the DHRS4-AS1/miR-139-5p/ARRDC3 axis participates in the regulation of EC-ESC function.

Clues for Improving the Pathophysiology Knowledge for Endometriosis Using Plasma Micro-RNA Expression.

The pathophysiology of endometriosis remains poorly understood. The aim of the present study was to investigate functions and pathways associated with the various miRNAs differentially expressed in patients with endometriosis. Plasma samples of the 200 patients from the prospective “ENDO-miRNA” study were analyzed and all known human miRNAs were sequenced. For each miRNA, sensitivity, specificity, and ROC AUC values were calculated for the diagnosis of endometriosis. miRNAs with an AUC ≥ 0.6 were selected for further analysis. A comprehensive review of recent articles from the PubMed, Clinical Trials.gov, Cochrane Library, and Web of Science databases was performed to identify functions and pathways associated with the selected miRNAs. In total, 2633 miRNAs were found in the patients with endometriosis. Among the 57 miRNAs with an AUC ≥ 0.6: 20 had never been reported before; one (miR-124-3p) had previously been observed in endometriosis; and the remaining 36 had been reported in benign and malignant disorders. miR-124-3p is involved in ectopic endometrial cell proliferation and invasion and plays a role in the following pathways: mTOR, STAT3, PI3K/Akt, NF-κB, ERK, PLGF-ROS, FGF2-FGFR, MAPK, GSK3B/β–catenin. Most of the remaining 36 miRNAs are involved in carcinogenesis through cell proliferation, apoptosis, and invasion. The three main pathways involved are Wnt/β–catenin, PI3K/Akt, and NF–KB. Our results provide evidence of the relation between the miRNA profiles of patients with endometriosis and various signaling pathways implicated in its pathophysiology.

Down-regulation of circ_0061140 attenuates ectopic endometrial cell proliferation, migration and invasion in endometriosis via inactivating Notch2.

Endometriosis is a frequent gynecologic disease in the world. CircRNAs can exert a crucial role in various diseases. Nevertheless, little is known about its roles in endometriosis. We investigated the involvement of circ_0061140 in endometriosis. Tissues from endometriosis women displayed an increased expression of circ_0061140. Then, we found loss of circ_0061140 significantly repressed ectopic endometrial cell proliferation, migration and invasion. Meanwhile,miR-140-3pcan demonstrate an important role in several cancers.Here, we reported miR-140-3p was reduced in ectopic endometrial cells and it acted as a target of circ_0061140. Moreover, miR-140-3p was able to reverse the effect of circ_0061140 on ectopic endometrial cells. Furthermore, Notch2 was predicted as a putative target of miR-140-3p. A positive correlation between circ_0061140 and Notch2 was indicated. miR-140-3p and Notch2 were operated as downstream effectors in the circ_0061140 mediated signaling in endometriosis. Decrease of circ_0061140 could depress endometriosis progression through modulating miR-140-3p and Notch2.

Role of thyroid dysimmunity and thyroid hormones in endometriosis

Endometriosis is characterized by the presence of ectopic endometrial cells outside the uterine cavity. Thyroid autoimmunity has been associated with endometriosis. This work investigated the potential pathophysiological link between endometriosis and thyroid disorders. Transcripts and proteins involved in thyroid metabolism are dysregulated in eutopic and ectopic endometrium of endometriotic patients, leading to resistance of ectopic endometrium to triiodothyronine (T3) action and local accumulation of thyroxine (T4). Thyroid-stimulating hormone (TSH) acts as a proliferative and prooxidative hormone on all endometria of endometriosis patients and controls, whereas T3 and T4 act to specifically increase ectopic endometrial cell proliferation and reactive oxygen species (ROS) production. Mouse studies confirmed the data gained in vitro since endometriotic implants were found to be bigger when thyroid hormones increased. A retrospective analysis of endometriosis patients with or without a thyroid disorder revealed an increased chronic pelvic pain and disease score in endometriotic patients with a thyroid disorder.

LncRNA-H19 regulates cell proliferation and invasion of ectopic endometrium by targeting ITGB3 via modulating miR-124-3p

Endometriosis, a common gynecological disease, is associated with pelvic pain and infertility. Endometriosis affects approximately 10% of women, but that number increases to 30–50% in symptomatic premenopausal women. Despite the prevalence of endometriosis, the cause has yet to be fully elucidated. Recent study of the molecular pathways of endometrial cancer has brought the long non-coding RNA (lncRNA) H19 to our attention. In this paper, we explored the role of lncRNA-H19 in endometrial tissue proliferation. We found that ectopic endometrial cells taken from women with endometriosis showed elevated levels of lncRNA-H19, with expression levels correlating to disease progression. Knockdown of H19 in ectopic endometrial cells inhibited cell proliferation and invasion. Coinciding with this change was an increase in microRNA-124-3p (miR-124-3p) and a decrease in integrin beta-3 (ITGB3) levels. The addition of a miR-124-3p inhibitor mitigated this decrease in ITGB3. Up-regulation of miR-124-3p markedly suppressed ITGB3 expression by binding to the 3′ untranslated region (3’ UTR), while inhibition of miR-124-3p had the opposite effect. ITGB3 overexpression potently counteracted the effects of miR-124-3p mimics on ectopic endometrial cells. From these results, we can infer that in endometriosis both miR-124-3p and ITGB3 operate as downstream effector proteins in the H19-signaling pathway. Down-regulation of lncRNA-H19 could inhibit ectopic endometrial cell proliferation and invasion by modulating miR-124-3p and ITGB3, offering a novel target for treatment.

MicroRNA-2861 targets STAT3 and MMP2 to regulate the proliferation and apoptosis of ectopic endometrial cells in endometriosis.

This study aimed to elucidate the roles and regulatory mechanism of miR-2861 in the development of endometriosis. The expression of miR-2861 in endometriotic tissues and eutopic endometrial tissues was determined. Ectopic endometrial cells were transfected with miR-2861 mimic, miR-2861 inhibitor and their corresponding controls. The effects of miR-2861 overexpression and inhibition on cell proliferation and apoptosis were then investigated. In addition, regulatory relationship between miR-2681 and signal transducer and activator of transcription 3 (STAT3) or matrix metalloproteinase 2 (MMP2) was explored, as well as between STAT3 and MMP2. Compared with eutopic endometrial tissues, miR-2861 was significantly downregulated in endometriotic tissues. Overexpression of miR-2861 markedly inhibited ectopic endometrial cell proliferation and induced apoptosis. Additionally, STAT3 and MMP2 were confirmed as the targets of miR-2861, and the effects of knockdown of STAT3 or MMP2on regulating cell proliferation and apoptosis were opposite with inhibition of miR-2861. Besides, STAT3 could enhance the expression of MMP2 in ectopic endometrial cells. Our study reveals that miR-2861 was lowly expressed in endometriotic tissues, and downregulation of miR-2861 may promote proliferation and inhibit apoptosis of ectopic endometrial cells in endometriosis via upregulation of STAT3 and MMP2. miR-2861 may be a potential biomarker or therapeutic target for endometriosis.

How Artificial Intelligence Can Improve Our Understanding of the Genes Associated with Endometriosis: Natural Language Processing of the PubMed Database.

Endometriosis is a disease characterized by the development of endometrial tissue outside the uterus, but its cause remains largely unknown. Numerous genes have been studied and proposed to help explain its pathogenesis. However, the large number of these candidate genes has made functional validation through experimental methodologies nearly impossible. Computational methods could provide a useful alternative for prioritizing those most likely to be susceptibility genes. Using artificial intelligence applied to text mining, this study analyzed the genes involved in the pathogenesis, development, and progression of endometriosis. The data extraction by text mining of the endometriosis-related genes in the PubMed database was based on natural language processing, and the data were filtered to remove false positives. Using data from the text mining and gene network information as input for the web-based tool, 15,207 endometriosis-related genes were ranked according to their score in the database. Characterization of the filtered gene set through gene ontology, pathway, and network analysis provided information about the numerous mechanisms hypothesized to be responsible for the establishment of ectopic endometrial tissue, as well as the migration, implantation, survival, and proliferation of ectopic endometrial cells. Finally, the human genome was scanned through various databases using filtered genes as a seed to determine novel genes that might also be involved in the pathogenesis of endometriosis but which have not yet been characterized. These genes could be promising candidates to serve as useful diagnostic biomarkers and therapeutic targets in the management of endometriosis.

Correlation between serum and peritoneal fluid glutathione S-transferases T1 concentration with different stages of endometriosis

Abstract Endometriosis is a gynecological disease defined by the histological presence of endometrial glands and stroma outside the uterine cavity. Ectopic endometrial cell proliferation and chronic inflammation in endometriosis were shown to be associated with oxidative stress (OS) induction. OS is a condition in which reactive oxygen species (ROS) overproduction and antioxidant deficiency cause a shift in oxidant/antioxidant balance. Glutathione S-transferases (GSTs) comprise a family of eukaryotic and prokaryotic phase II metabolic isozymes best known for their ability to catalyze the conjugation of the reduced form of glutathione (GSH) to xenobiotic substrates for the purpose of detoxification. The aim of this project was to study the concentrations of GSTT1 in the serum and peritoneal fluid (PF) of patients with different stages of endometriosis. Frothy two PF and serum from normal and 152 from different stages of patients with endometriosis (stage I: n = 30, stage II: n = 39, stage III: n = 43 and stage IV: n = 40) were included in this study. The level of GSTT1 in the serum was determined by enzyme linked immunosorbent assay (ELISA). The results showed the presence of GSTT1 in all serum and peritoneal fluid samples, while, starting from stages I to IV endometriosis, a significant decrease in GSTT1 concentration was seen as compared to controls. It is concluded that levels of GSTT1 is negatively correlated with advanced stages of endometriosis. It is also suggested that the detection of serum and/or peritoneal fluid GSTT1 concentration may be valuable in the classifying of endometriosis.

A PubMed-wide study of endometriosis

Endometriosis affects 5–10% of women in reproductive age, leading to dysmenorrhea, pelvic pain and infertility; however, our understanding on the pathogenesis of this disease remains incomplete. In the present study, we performed a systematic analysis of endometriosis-related genes using text mining. Taking text mining results as input, we subsequently generated a filtered gene set by computing the likelihood of finding more than expected occurrences for every gene across the disease-centered subset of the PubMed database. Characterization of this filtered gene set by gene ontology, pathway and network analysis provides clues to the multiple mechanisms hypothesized to be responsible for the establishment of ectopic endometrial tissues, including the migration, implantation, survival and proliferation of ectopic endometrial cells. Finally, using this gene set as “seed”, we scanned human genome to predict novel candidate genes based on gene annotations from multiple databases. Our study provides in-depth insights into the pathogenesis of endometriosis.

Genetic polymorphisms in patients with endometriosis: an analytical study in Goiânia (Central West of Brazil).

In healthy women, intra- and extracellular controls prevent the attachment and proliferation of ectopic endometrial cells. During endometriosis, abnormalities in these control mechanisms permit the survival of endometrial cells, their subsequent attachment to the peritoneal cavity, and disease progression. These abnormal cells cause invasion of tissues and induce an inflammatory response. Several genetic, immunological, and environmental factors contribute to this complex process. In this study we examined 6 polymorphisms for 6 different genes (p53; estrogen receptor β; progesterone receptor; GSTM1; GSTT1; CYP1A1). We obtained polymorphic genotype frequencies of all genes for 50 patients and analyzed them using the Fisher exact test or G test. Initially, we analyzed the genes in groups of 2, followed by 3. We found a significant association between polymorphisms in 6 pairs of genes (p53-ERβshowed 5.9-times higher frequency in the experimental group, p53-GSTM1 showed 2.39 times higher, 65.5% patients showed p53-CYP1A1 polymorphism, ERβ-PROGINS showed 3.0-times higher frequency, while 31.25% patients showed GSTM1- PROGINS and GSTT1-CYP1A1 polymorphism). Positive results were found in 15 situations when genes were analyzed in groups of 3; the most significant result corresponded to polymorphisms of p53, ERβand GSTM1 seen in 20%; PROGINS, ERβand GSTM1 in 18%; and p53, ERβand PROGINS in 12% patients. The results indicate that the presence of polymorphisms in more than one endometriosis-related gene is associated with onset of disease and progression. Future studies should focus on these genes to understand their inter-relationships and explore the possibility of developing new diagnostic techniques based on molecular markers.

Role of epidermal growth factor signaling system in the pathogenesis of endometriosis under estrogen deprivation conditions

To study the role of epidermal growth factor (EGF) , epidermal growth factor receptor(EGFR), extracellular signal-regulated kinase 1/2 (p-ERK1/2) in the pathogenesis of endometriosis under estrogen deprivation conditions. The estrogen was quickly-stripped in medium and the female nude mice were castrated by bilateral oophorectomy to build estrogen deprivation in vitro and in vivo experimental models, respectively. (1) In vitro experiments:according to different treatments the estrogen deprived ectopic endometrial cells were classified into 4 groups: a. EGF group:the ectopic endometrial cells were cultured for 72 hours with different concentrations of EGF (0.01, 0.1, 1, 10, 50, 100 ng/ml), the results of EGF group were represented by the result of cells treated by 10 ng/ml EGF cultured for 72 hours; b. EGF+PD98059 group:the ectopic endometrial cells were cultured for 72 hours with 5×10(-2) mol/L PD98059 (inhibitor of ERK), followed by a cultivation for 72 hours treated by 10 ng/ml EGF+5×10(-2) mol/L PD98059; c. EGF+ ICI182780 group: the ectopic endometrial cells were cultured for 72 hours with 10(-6) mol/L ICI182780 [inhibitor of estrogen receptor(ER)], followed by a cultivation for 72 hours treated by 10 ng/ml EGF+10(-6) mol/L ICI182780; d. Blank control group:the ectopic endometrial cells were cultured with no treatment. The proliferation activity of ectopic endometrial cells in all groups after treatment were examined by methyl thiazolyl tetrazolium (MTT) method represented by absorbance value (A). The expression of p-ERK1/2 protein were detected by western blot. (2) In vivo experiments: 64 female nude mice were randomly divided into control and castration groups (both n=32) using random number chart. The mice in castration group were castrated by bilateral oophorectomy on 3 weeks after the endometriosis model was established. The levels of EGF, EGFR, p-ERK1/2 protein in ectopic lesions of both groups were measured on 4, 6, 8 and 10 weeks after the endometriosis model was established by western blot. (1) The proliferation activity of ectopic endometrial cells:the proliferation activity of ectopic endometrial cells treated by different concentrations of EGF (0.01, 0.1, 1, 10, 50, 100 ng/ml) for 72 hours were 0.310±0.010, 0.340±0.020, 0.670±0.010, 0.980±0.030, 1.360±0.020, 1.670±0.020, respectively, the proliferation activity was increased along with of EGF concentrations.The proliferation activity was 0.680±0.030 at EGF+ PD98059 group, the differences exhibited significant difference when compared with that at EGF group with 100 ng/ml for 72 hours (P<0.01) .The proliferation activity of EGF+ ICI182780 and blank control groups were 0.330±0.030 and 0.310±0.030, respectively, which did not reached statistical differences (P>0.05). (2) The expression of EGF, EGFR, pERK1/2 protein: a. In vitro experiments:the levels of p-ERK1/2 protein in EGF and blank control groups were 0.670±0.020 and 0.600±0.010, respectively, which reached statistical differences (P<0.05). The level of p-ERK1/2 protein in EGF+ PD98059 group was 0.610±0.020, which exhibited significant differences with that at blank control group (P>0.05). b. In vivo experiments:at 4, 6 and 8 weeks after the endometriosis models were established, the expression of EGF protein in the ectopic lesions of castration group and control group were (0.530±0.015 versus 0.610±0.015), (0.400±0.029 versus 0.620±0.018), (0.560±0.026 versus 0.630±0.021), respectively, the levels of EGFR protein were (0.500±0.030 versus 0.640±0.030), (0.470±0.020 versus 0.630±0.020), (0.510±0.030 versus 0.610±0.020) respectively, and the level of p-ERK1/2 protein were (0.500±0.020 versus 0.580±0.020), (0.490±0.020 versus 0.580±0.020), (0.570±0.020 versus 0.590±0.020), respectively. The difference of EGF, EGFR, p-ERK1/2 protein expression levels between two groups did not exhibited significant difference (P<0.01, P<0.01, P<0.05). At 10 weeks after the endometriosis models were established, the levels of EGF protein in castration group and control group were both 0.620±0.020, the levels of EGFR protein were both 0.610±0.020, and the level of p-ERK1/2 protein were 0.590±0.010 and 0.600±0.020. No statistical difference (P>0.05) was found between those two groups (P>0.05). EGF could stimulate the proliferation of ectopic endometrial cells by activating the ERK pathway under estrogen deprivation conditions. The inhibition of EGF signaling system in ectopic lesions was alleviated along with the prolongation of the period of estrogen deprivation.

High expression levels of cyclin B1 and Polo-like kinase 1 in ectopic endometrial cells associated with abnormal cell cycle regulation of endometriosis

To investigate the possible roles of cyclin B1/cyclin-dependent kinase (cdc2) and Polo-like kinase 1 (Plk1) in the pathogenesis of endometriosis. A case-control study. University hospital. Patients with or without endometriosis were diagnosed by pathological examination or laparoscopy. The patients with the following criteria within the past 6 months were excluded: endocrine or inflammatory diseases, pregnancy or lactation, hormonal therapy, and neoplasm in the uterine cavity. Eutopic and ectopic endometria were obtained at the time of surgery. Blood was collected on the same day as surgery. The mRNA/protein expression and localization of cyclin B1, cdc2, and Plk1 in endometrium, and serum levels of E(2) and P. The expression levels of cyclin B1 and Plk1, but not cdc2, in ectopic endometria were significantly higher than in eutopic endometria. The immunohistochemical staining of cyclin B1 and Plk1 was detected in the nuclei of ectopic and eutopic endometrial cells. Furthermore, ectopic endometrial expression levels of cyclin B1 or Plk1 were positively correlated with serum E(2) levels. Cyclin B1 and Plk1 may play important roles in the pathogenesis of endometriosis by mediating ectopic endometrial cell proliferation under regulation of ovarian hormones.

Peritoneal fluid-mediated enhancement of eutopic and ectopic endometrial cell proliferation is dependent on tumor necrosis factor-α in women with endometriosis

Objective: To determine the effect of autologous peritoneal fluid and tumor necrosis factor-α (TNF-α) on proliferation of endometrial cells from women with endometriosis. Design: Endometrial cells from eutopic and ectopic endometrium were cultured in vitro with peritoneal fluids or recombinant TNF-α for 72 hours before DNa synthesis determination by 3H-thymidine labeling and liquid scintillation counting. Setting: An institute for the study and treatment of endometriosis and university-based research laboratories. Patient(s): Thirty-five women with endometriosis and 17 controls without endometriosis. Main Outcome Measure(s): In vitro incorporation of 3H-thymidine in endometrial cells was examined. Result(s): Peritoneal fluid from women with endometriosis enhanced proliferation of autologous and heterologous endometrial cell cultures from women with endometriosis. The soluble TNF-receptor etanercept blocked the ability of peritoneal fluid from women with endometriosis to enhance proliferation of eutopic or ectopic endometrial cells. Recombinant TNF-α also enhanced proliferation of eutopic and ectopic endometrial cells from women with endometriosis. In contrast, autologous peritoneal fluid, heterologous peritoneal fluid from women with endometriosis, and recombinant TNF-α failed to enhance, and often inhibited, the proliferation of eutopic endometrial cells from controls without endometriosis. Conclusion(s): Endometrial cells from women with endometriosis can utilize factors in peritoneal fluids, such as TNF-α, to facilitate proliferation in ectopic environments. Endometrial cells from women without endometriosis do not share this ability, suggesting that this abnormality is etiologically related to development of the disease. Therapy with agents that block the effects of TNF-α may be warranted.