Prevalence of high-risk human papillomavirus infection in women with ovarian endometriosis

Association of endometriosis with genital human papillomavirus infection in US women: a national population-based study

The prevalence of genital human papillomavirus (HPV) in women with endometriosis has never been reported in a national representative survey. We aimed to investigate the association of endometriosis with the prevalence of HPV. We analyzed the data on 1768 women (representing 43,824,157 women) in the United States aged 20-54 years from the National Health and Nutrition Examination Survey in the prevaccination era (2003-2006). The diagnosis of endometriosis was based on a self-report. The prevalence of any HPV in women with endometriosis did not differ from that in women without endometriosis after controlling for potential confounders such as age, ethnicity, family income, marital status, and the number of deliveries (adjusted prevalence ratio (aPR) 0.84, 95% confidence interval (CI) 0.61-1.15). No significant association was found between the prevalence of high-risk HPV and the diagnosis of endometriosis (aPR 0.71, 95% CI 0.44-1.14). If the participants were not covered by health insurance, the prevalence of any HPV infection in women with endometriosis was higher than in those without endometriosis (aPR 1.44, 95% CI 0.94-2.20). In contrast, in a subgroup who had health insurance, a lower prevalence of any HPV infection was observed in women with endometriosis (aPR 0.71, 95% CI 0.50-1.03), and P for interaction was statistically significant (P = 0.01). There was no association between endometriosis and HPV infection in this study of HPV vaccine-naïve women of reproductive age. The association was not different by the type of HPV. However, access to healthcare may modify the association between endometriosis and HPV infection.

Exploring the potential impact of human papillomavirus on infertility and assisted reproductive technology outcomes

Human papillomavirus (HPV) is a common sexually transmitted disease that has been linked to both cancer and reproductive health issues. While its impact on fertility and pregnancy success has been studied, there is still too little evidence about the influence of HPV on assisted reproductive technology (ART). Therefore, there exists a need for HPV testing in couples undergoing infertility treatments. Infertile men have been found to have a higher prevalence of seminal HPV infection, which can compromise sperm quality and reproductive function. As such, it could be important to investigate the correlation between HPV and ART outcomes in order to improve the quality of evidence. Understanding the potentially detrimental effects of HPV on ART outcomes may have promising important implications for the management of infertility. This minireview summarizes the so far limited developments in this area and highlights the major need for further well-designed studies to address this issue.

Correlation of High-Risk Human Papilloma Virus with Deep Endometriosis: A Cross-Sectional Study

Background

Recently, it has been suggested that microbial infections play a role in the pathogenesis of endometriosis. One of the most commonly suggested infections associated with the pathogenesis of endometriosis is human papillomavirus (HPV) infection. The present study is aimed at evaluating the prevalence, types, and risk factors for HPV infection in women with endometriosis and at investigating the association of upper and lower genital tract involvement with HPV and the severity of endometriosis.

Methods

This cross-sectional study was conducted on 81 patients with endometriosis, referred to Rasool Akram Medical Complex in Tehran, Iran, for laparoscopic surgery. The patients' demographic, clinical, and anthropometric data were extracted from their medical records, as well as interviews. The stage of disease was scored based on the revised American Society for Reproductive Medicine (rASRM) classification. The HPV-positive and HPV-negative cases were compared using the chi-square test for categorical variables and Student t-test for continuous variables.

Results

Twenty (24.69%) out of 81 women with endometriosis were infected with HPV (nine cases of pelvic HPV, nine cases of vaginal HPV, and two cases of both pelvic and vaginal HPV). The HPV-infected women had a significantly lower infertility rate (15% vs. 45.9%; P = 0.014). The VAS scores for dysmenorrhea and dyspareunia were relatively the same in the two groups (P > 0.05). HPV 6 and HPV 11 were the most common types of HPV, reported in 35% and 30% of endometriosis cases, respectively.

Conclusion

The prevalence of HPV was 24.69%, and low-risk genotypes were dominant. No significant association was found between HPV and the severity of endometriosis.

Integrated analysis of genome-wide gene expression and DNA methylation profiles reveals candidate genes in ovary endometriosis

BACKGROUND

The incidence of endometriosis (EMs), a common disease in gynecology, has increased over the years. Women suffer from the symptoms caused by EMs, such as chronic pelvic pain, dysmenorrhea, and infertility. However, the etiology and pathophysiology of EMs remain unclear. This study aimed to identify candidate genes of endometriosis through integrated analysis of genome-wide gene expression and DNA methylation profiles.

RESULTS

Eutopic and ectopic endometrial tissues were collected from patients who were diagnosed as ovarian EMs. Genome-wide methylation profiling identified 17551 differentially methylated loci, with 9777 hypermethylated and 7774 hypomethylated loci. Differentially methylated loci were mainly concentrated in the gene body and intergenic regions. Genome-wide gene expression profiling identified 1837 differentially expressed genes (DEGs), with 1079 genes upregulated and 758 downregulated in ectopic groups. Integrated analysis revealed that DNA methylation was negatively correlated to gene expression in most genomic regions, such as exon, 3'UTR, 5'UTR, and promoter. We also identified promoter-related (53 downregulated and 113 upregulated) and enhancer-related DMGs (212 downregulated and 232 upregulated), which were significantly correlated to the gene expression. Further validation of the top-ranked genes belonging to differentially methylated genes (DMGs) and DEGs revealed that TMEM184A, GREM2, SFN, KIR3DX1, HPGD, ESR1, BST2, PIK3CG and RNASE1 were significant candidate genes in ovarian endometriosis.

CONCLUSION

Our study revealed the significance of DNA methylation in the gene expression in ovary endometriosis, which provides new insights and a molecular foundation for understanding the underlying mechanisms of endometriosis.

The bidirectional relationship between endometriosis and microbiome

Endometriosis has been described by many different theories of pathogenesis over the years. It is now also appreciated to be a state of chronic inflammation, and the role of immune dysfunction in its development has been proven. There is increasing evidence to support the role of the microbiome in the formation and progression of endometriosis via inflammatory pathways. The dysbiosis seen in endometriosis is thought to be both causative and a consequence of the pathogenesis. Gut, peritoneal fluid and female reproductive tract microbiota has been studied to understand if there are any microbiome signatures specific to endometriosis. New research on how to manipulate the microbiome for better detection and treatment of endometriosis is emerging.

Human papillomavirus prevalence in unexplained infertile women with chronic endometritis

Introduction: This study investigates unexplained infertile women with or without chronic endometritis (CE) and examines the prevalence of the human papillomavirus (HPV) in this population. Material and Method: This study was done with a cross-sectional and retrospective method. The prevalence of HPV infection and related cases in the participants were examined. In this study, 15 infertile women with CE and 64 infertile women without CE were and analyzed from four perspectives: negative HPV, low-risk HPV, probable high-risk HPV, and the presence of high-risk HPV. Results: The participants have mean age of 32.89 years ±3.95. High-risk HPV infection was detected in 3 (20%) and 11 (17%) of the patients with and without CE, respectively (p>0.05). The negative HPV (2 (13%) and 17 (26%)), low-risk HPV (3 (20%) and 20 (31%)), and probable high-risk HPV (7 (46%) and 16 (25%)) in infertile women with CE and infertile women had no significantly different prevalence (p>0.05). The two studied groups had no significantly different mean age, body mass index (BMI), and Infertility duration were not in (P=0.08, P=0.932, and P=0.283, respectively). Conclusion: HPV has no significantly different prevalence in unexplained infertile women with and without CE. It is recommended that this study be repeated with more unexplained infertile women with CE.

Coexistence of cervical endometriosis with premalignant and malignant gynecological pathologies: report on a series of 27 cases

Although cervical endometriosis represents a rare condition, there is evidence that implicates a complex interaction with other gynecological pathologies. This study aims to highlight this entity and further to explore the impact of oncological pathology of female genital tract on patients with cervical endometriosis. We retrospectively investigated the medical and pathological reports of 27 cases with cervical endometriosis, which were diagnosed by tissue biopsy. The results of the study show a relationship between CIN (cervical intraepithelial neoplasia) cases 19/27 (70percent) and cervical endometriosis. CIN I was more frequently found compared to patients with CIN II and CIN III. Furthermore, a high prevalence of HPV (human papilloma virus) was confirmed. Out of 27 patients, 2 cases with cervical (7.4percent), 2 with endometrial (7.4percent) and 3 with ovarian cancer (11.1percent) were detected. We confirmed the coexistence of more than one malignant gynecological pathology with cervical endometriosis in four cases (14.8percent). To conclude, cervical endometriosis is a rare disease co-existing considerably with premalignant and malignant gynecological conditions according to our data. Although the pathophysiology and genetics of cervical dysplasia is well delineated, further research is needed to establish the association between cervical endometriosis and gynecological premalignant and malignant pathology.

The Impact of 9-Valent HPV Vaccination on Couple Infertility Prevention: A Comprehensive Review

A comprehensive literature review was performed to determine the relationship between HPV infection and infertility and the eventual role of the 9-valent vaccine for infertility prevention. The search was extended from January 1997 through July 2021. Data collected from selected articles focused on three main topics: statistical associations between HPV prevalence and assisted reproductive technology (ART) outcome, association between HPV and characteristics of semen, and associations between HPV and miscarriage. Articles that identified HPV genotypes were selected for this review to study the possible role of the 9-valent vaccine in infertility prevention. To date, there is no agreement on the implication HPV female infection has on the fertility and miscarriage rate. Although it can be stated that HPV prevalence among couples with infertility undergoing ART treatment is consistent, it does not seem to affect the performance of oocytes. Otherwise, HPV infection affects sperm parameters, in particular spermatozoa motility. When an association can be found, most cases of HR-HPV involved are those included in the 9-valent vaccine. The correlation between HPV male infection both with asthenozoospermia and increased risk of pregnancy loss could recommend the extension of anti-HPV vaccination to adolescent males along with cancer prevention. Despite the fact that the relation between 9-valent HPV genotypes involved in female infection and miscarriage/infertility is not clear, the impact of this virus on health reproduction is evident. Considering this, the importance of HPV vaccination in adolescent females is confirmed. A vaccine efficacy study could be useful to confirm the importance of primary prevention for couple reproductive health.

Molecular and Clinical Insights on the Complex Interaction between Oxidative Stress, Apoptosis, and Endobiota in the Pathogenesis of Endometriosis

Endometriosis (EMS) remains, to date, an intriguing and debilitating gynecological disorder that possesses a multifactorial substrate. Recent studies with the objective of elucidating its etiology highlighted the antagonistic effect of EMS on a multiple of processes involved in homeostasis. Although the current oxidative biomarkers clearly reveal the consequences induced by EMS, its implication in the associated inflammatory reactions could be much more complex. Besides the overproduction of reactive oxygen species (ROS) that leads to an exacerbated oxidative response, it also changes the normal expression of several pro-inflammatory modulators, reflected by the fluctuating activity of several pro- and anti-apoptotic mediators whose expression is impaired. In light of this topic, several studies elucidate the involvement of apoptosis in EMS, being brought controversial findings, even reports with no significant change. Further, some authors reported an abnormal expression of multiple genes that are crucial for the overall functionality of the female reproductive system. Cumulatively, it seems that the subsequent oxidative imbalance and apoptosis process impairment could further disrupt the normal removal of unnecessary biological products. Based on all gathered evidence, we could argue that the related stress state could determine human endobiota impairment, which could further participate in the inflammatory and main antioxidant enzyme changes occurring in EMS. Moreover, a correlation between endobiota integrity, inflammation, and oxidative stress (OS) was suggested in relation to the possible predisposition to pathogen determined infections.

Target identification and drug discovery by data-driven hypothesis and experimental validation in ovarian endometriosis

OBJECTIVE

To identify targets and discover drugs for ovarian endometriosis (OE) DESIGN: A basic study based on a data-driven hypothesis and experimental validation SETTING: Center for Reproductive Medicine PATIENT(S)/ANIMAL(S): Fourteen patients with OE and 7 healthy donors were recruited, and 15 female C57/BL6 mice were involved.

INTERVENTION(S)

Samples of OE lesions and normal endometrium were obtained. The ITPR1-knockdowned ectopic human endometrial stromal cells (HESCs) were subjected to ribonucleic acid (RNA) sequencing, cell-counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, and flow cytometry. Camptothecin was administered to HESCs and in an OE mouse model.

MAIN OUTCOME MEASURE(S)

ITPR1 expression in OE lesions and normal endometrium, cell proliferation and apoptosis of HESCs with ITPR1 knockdown or camptothecin treatment, and autograft volume in the OE mouse model RESULT(S): Two significant OE-relevant gene modules were identified and involved the PI3K/Akt and aging-relevant pathways. Fifteen hub genes were identified and confirmed, among which the most significant gene, ITPR1, was robustly elevated in OE lesions. RNA sequencing revealed that ITPR1 was highly relevant to cell proliferation and apoptosis, which was further confirmed by CCK-8 assay, EdU staining, and flow cytometry analysis. ITPR1 knockdown inhibited cell proliferation and induced HESC apoptosis. The candidate drugs targeting these modules were screened, among which camptothecin and irinotecan were identified as promising drugs. Both compounds suppressed HESC proliferation and induced apoptosis; ITPR1 expression was suppressed by camptothecin. The therapeutic effect of camptothecin was also validated in the OE mouse model.

CONCLUSION(S)

This study identified the therapeutic targets and promising drugs for OE and shed light on the use of camptothecin in OE treatment.

Peritoneal HPV-DNA test in cervical cancer (PIONEER study): A proof of concept

The aim of this study was to investigate the prevalence of peritoneal human papillomavirus (HPV) infection in different clinical cervical cancer (CC) settings, and its association with potential clinical and/or histological factors. This is a single-center, prospective, observational study. Consecutive patients with newly diagnosed or recurrent/persistent CC, between March 2019 and April 2020, were included. A group of patients undergoing surgery for benign gynecological conditions was included as control group. All patients underwent HPV-DNA test in the cervix and in the peritoneal cavity simultaneously at time of surgery. Two-hundred seventy-two patients had cervical and peritoneal HPV test analyzed. Cervical and peritoneal HPV positivity (PHP) was found in 235 (88.0%) and 78 (28.7%) patients, respectively; the prevalence of PHP was 17.7% in early stage, 28.8% in locally advanced cervical cancer (LACC) and 46.6% in the metastatic/persistent/recurrent setting (P = .001). No control patient was found to have peritoneal HPV infection. Higher frequency of PHP was documented in patients with larger tumor size (P = .003), presence of cervical HPV 16/18 genotypes (P < .001), higher number of cervical high-risk (HR)-HPV per patient (P = .018) and peritoneal carcinomatosis (P < .001). Multivariate analysis demonstrated that lack of preoperative cervical conization in early stages (P = .030), while higher International Federation of Gynecology and Obstetrics (FIGO) stage (P = .021) and presence of cervical HPV 16/18 (P = .001) in LACC, was associated with PHP. This is a proof-of-concept study. A number of potential clinical implications, including prognosis, could be obtained by further studies.

Female Human Papillomavirus Infection Associated with Increased Risk of Infertility: A Nationwide Population-Based Cohort Study

Objective. This study investigated whether women with a history of human papillomavirus (HPV) infection have an increased risk of infertility. Material and Methods. All patients with an HPV infection (n = 11,198) in Taiwan’s National Health Insurance Research Database (2000–2012) were propensity score matched with control subjects (n = 11,198) without an HPV infection by age, sex, index year, and relevant co-morbidities. Both groups were tracked until a diagnosis of infertility was recorded. The Chi-square test was used to analyze the distribution of demographic characteristics in the HPV group and non-HPV group. A Cox proportional hazards regression was used to estimate the hazard ratios (HRs) for the development of infertility, adjusting for age, sex, and co-morbidities. The Kaplan–Meier method was used to plot the cumulative incidence curves. We also performed negative controls to test for possible unmeasured confounding. Results. The HPV cohort had a higher risk of infertility. The adjusted HR (aHR) was found to be 1.39 (95% CI = 1.19–1.63) after adjusting for demographic characteristics and relevant co-morbidities. In the age subgroup analysis, patients with an HPV infection had an increased risk of infertility compared to the non-HPV cohort in the group aged 26 to 35 years (aHR, 1.53; 95% CI = 1.24–1.88). As we used propensity score matching to treat measurable confounders and negative controls to access unmeasured confounders, the findings of the study are robust. Conclusions. Among females of reproductive age, HPV infection is a potential risk factor that predisposes individuals to subsequent infertility.

The effects of human immunodeficiency virus, human papillomavirus, herpes simplex virus-1 and -2, human herpesvirus-6 and -8, cytomegalovirus, and hepatitis B and C virus on female fertility and pregnancy

Female infertility may be defined as a woman of reproductive age being unable to become pregnant after a year of regular unprotected sexual intercourse. Social, genetic, endocrine, physiological, and psychological factors as well as lifestyle habits (i.e., smoking and alcohol consumption), either alone or in combination with male factors, are major causes. However, approximately 15-30% of cases of female infertility remain unexplained. Numerous investigations have also indicated that microbiomes play an important role in human reproduction. All parts of the female reproductive system may be influenced by infectious and pathological agents, especially viruses, and these may interfere with reproductive function and so are risk factors for infertility, although in many cases an exact role is unclear. We present an overview of the impact of common viral infections on female reproduction, searching Medline, PubMed, Scopus, and Google scholar databases for potentially relevant studies of viruses known to have a potential effect. Human immunodeficiency virus (HIV), herpes simplex virus (HSV) and human herpesvirus (HHV) increase infertility rates whilst human papillomavirus (HPV), cytomegalovirus (CMV), and hepatitis B and C virus (HBV, HCV) infections mostly lead to higher abortion and miscarriage rates. Moreover, HPV infection is linked to increased tubal infertility, endometriosis, and pelvic inflammatory disease. HPV was the most frequently observed infection and with lower pregnancy rate and foetal death in women undergoing IVF treatments. Assisted reproductive treatment could be a safe and effective approach for HIV and HBV infected women.

Features of local immunity in women with endometriosis and genital infection

Introduction. External genital endometriosis is an inflammatory estrogen-dependent disease characterized by implantation and proliferation of endometrial tissue outside the uterus, accompanied by increased production of proinflammatory cytokines, prostaglandins, components of the complement, hydrolytic enzymes, increased angiogenesis and anomalies of ectopic endometrium. According to implantation theory, external genital endometriosis develops from viable endometrial cells transferred retrogradely through the fallopian tubes to the abdominal cavity during menstruation, while a disturbed local immunity is an important factor in its pathogenesis. Genital pathogens may be involved in the formation of the immune environment of the peritoneal cavity in women with endometriosis.Purpose. To study the peculiarities of local immunity in women with external genital endometriosis and genital infection pathogens.Materials and methods. 159 women with external genital endometriosis were examined. The total number of leukocytes, the absolute and relative number of viable cells, counts of neutrophils, macrophages and their functional activity, the level of IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFNα, IFNγ, TNFα in the peritoneal fluid were evaluated. The study of local immunity was performed in women with endometriosis, stage 1—2 and 3—4, depending on detected genital pathogens. Chlamydia trachomatis, Ureaplasma spp., Mycoplasma genitalium, HSV1,2/CMV, high carcinogenic risk HPV were analyzed by using PCR in samples collected from the endometrium, peritoneal fluid, and endometrioid heterotopies. Statistical processing was performed by using the IBM SPSS Statistics Version 22.2 statistical analysis software package.Results. In the presence of HPV and Ureaplasma spp. in women with endometriosis, stage 1—2, the decreased functional activity of peritoneal neutrophils and macrophages was found. At 3—4 stage, a correlation analysis revealed that detected HPV and Ureaplasma spp. obtained increased both pro-inflammatory and anti-inflammatory cytokines in the peritoneum. However, the higher activity of Th-2 cells in the peritoneal fluid secreting IL-4 and IL-10 and suppressing cellular immunity, was observed in HPV-positive samples. In addition, HPV also correlated with a decreased IL-2 and IL-4 levels.Conclusions. The most prominent changes in the immunological parameters from peritoneal fluid samples were observed in case of detected genital infection pathogens, particularly HPV. Thus, immune disturbances emerged upon bacterial and viral pathogen detection may contribute to the implantation of endometrial cells in the pelvic organs and disease progression.

EXTL3-interacting endometriosis-specific serum factors induce colony formation of endometrial stromal cells

Endometriosis is a benign chronic condition characterized by the existence of endometrial-like stroma and glandular tissue in extrauterine locations. The molecular mechanisms of its pathogenesis have not been elucidated. We have studied the role of EXTL3 (exostosin-like 3) in endometriosis and found that it is expressed in endometrial tissue as well as endometriosis lesions. We have found that serum from endometriosis patients contains a factor or factors, which interact with EXTL3 resulting in strongly increased colony formation in regenerating cell culture. We also found increased anti-EXTL3 antibodies in endometriosis patients’ sera. EXTL3 is an N-acetyl glucosamine (GlcNAc) transferase, performing a key step in heparan sulfate (HS) glucosaminoglycan synthesis. Many viruses replicate in regenerating epithelial cells and use HS as a receptor for cell entry. We measured antibody titres to viruses, which use HS as a receptor for cell entry, and found rarely increased titres for these viruses in endometriosis sera, whereas titres to viruses using other receptors were equally distributed in study groups. The data indicate that perturbation of HS metabolism is associated with endometriosis.

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

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

The high-risk human papillomavirus continuum along the female reproductive tract and its relationship to infertility and endometriosis

RESEARCH QUESTION

Is there an association between the presence of sexually transmitted pathogens in the lower (LGT) and upper (UGT) female genital tract with endometriosis and infertility?

DESIGN

Case-control study with 60 women submitted to gynaecological laparoscopic surgery. Samples from the UGT and LGT were collected and analysed by single polymerase chain reaction (PCR) for human papillomavirus (HPV) and by multiplex PCR for other sexually transmitted infections (STI). Patients were initially divided into two clinical groups: infertile patients (n = 25) with conjugal infertility and fertile control patients (n = 35). After the surgical findings patients were further divided for additional analysis: an endometriosis group (n = 29) and non-endometriosis control group (n = 31).

RESULTS

Sixty per cent of patients were positive for DNA-HPV in some of the genital tract sites sampled. Infertile patients were associated with high-risk HPV (hrHPV) positivity in the UGT sites (P = 0.027). The endometriosis group was associated with hrHPV positivity in the LGT and UGT sites (P = 0.0002 and P = 0.03, respectively). Only hrHPV types were detected in the UGT in both groups. It may be that there is a hrHPV infection continuum, from LGT to UGT, in infertile and endometriosis patients. No association was observed among the other seven STI studied.

CONCLUSIONS

This study shows both an association between hrHPV infections in the UGT with infertility and endometriosis, and a possible hrHPV infection continuum, from LGT to UGT. Larger studies are needed to fully investigate the role of hrHPV as a cause of endometriosis and infertility.

Pathogenesis of endometriosis: the genetic/epigenetic theory

OBJECTIVE

To study the pathophysiology of endometriosis.

DESIGN

Overview of observations on endometriosis.

SETTING

Not applicable.

PATIENT(S)

None.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

The hypothesis is compatible with all observations.

RESULT(S)

Endometriosis, endometrium-like tissue outside the uterus, has a variable macroscopic appearance and a poorly understood natural history. It is a hereditary and heterogeneous disease with many biochemical changes in the lesions, which are clonal in origin. It is associated with pain, infertility, adenomyosis, and changes in the junctional zone, placentation, immunology, plasma, peritoneal fluid, and chronic inflammation of the peritoneal cavity. The Sampson hypothesis of implanted endometrial cells following retrograde menstruation, angiogenic spread, lymphogenic spread, or the metaplasia theory cannot explain all observations if metaplasia is defined as cells with reversible changes and an abnormal behavior/morphology due to the abnormal environment. We propose a polygenetic/polyepigenetic mechanism. The set of genetic and epigenetic incidents transmitted at birth could explain the hereditary aspects, the predisposition, and the endometriosis-associated changes in the endometrium, immunology, and placentation. To develop typical, cystic ovarian or deep endometriosis lesions, a variable series of additional transmissible genetic and epigenetic incidents are required to occur in a cell which may vary from endometrial to stem cells. Subtle lesions are viewed as endometrium in a different environment until additional incidents occur. Typical cystic ovarian or deep endometriosis lesions are heterogeneous and represent three different diseases.

CONCLUSION(S)

The genetic epigenetic theory is compatible with all observations on endometriosis. Implications for treatment and prevention are discussed.