1 2575 78 EPIGENETICS OF ESTROGEN AND PROGESTERONE RECEPTORS IN ENDOMETRIOSIS. ENDOMETRIOSIS IS AN ESTROGEN-DEPENDENT INFLAMMATORY GYNECOLOGICAL DISEASE. INCREASED ESTROGEN ACTIVITY AND PROGESTERONE RESISTANCE ARE THE MAIN HORMONAL SUBSTRATE OF THIS DISEASE AND ARE ASSOCIATED WITH INFLAMMATORY RESPONSE AND DEBILITATING SYMPTOMS, INCLUDING PAIN AND INFERTILITY. ESTROGENS AND PROGESTERONE ACT VIA THEIR SPECIFIC NUCLEAR RECEPTORS. THE REGULATION OF RECEPTOR EXPRESSION BY EPIGENETICS MAYBE A CRITICAL FACTOR FOR ENDOMETRIOSIS. THE PRESENT REVIEW AIMS TO DISCUSS THE EPIGENETIC MECHANISMS RELATED TO THE EXPRESSION OF ESTROGEN RECEPTORS (ERS) AND PROGESTERONE RECEPTORS (PRS) IN PATIENTS WITH ENDOMETRIOSIS, INCLUDING TWO CLASSIC EPIGENETIC MECHANISMS: DNA METHYLATION AND HISTONE MODIFICATION, AND, OTHER NON-CLASSIC MECHANISMS: MIRNAS AND LNCRNA. SEVERAL IN VITRO AND IN VIVO STUDIES SUPPORT THE KEY ROLE OF EPIGENETICS IN THE REGULATION OF THE EXPRESSION OF ERS AND PRS, WHICH MAY PROVIDE NEW MOLECULES AND TARGETS FOR THE DIAGNOSIS AND TREATMENT OF ENDOMETRIOSIS. 2020 2 2602 41 EPIGENETICS, ENDOMETRIOSIS AND SEX STEROID RECEPTORS: AN UPDATE ON THE EPIGENETIC REGULATORY MECHANISMS OF ESTROGEN AND PROGESTERONE RECEPTORS IN PATIENTS WITH ENDOMETRIOSIS. ENDOMETRIOSIS IS A BENIGN GYNECOLOGICAL DISEASE AFFECTING APPROXIMATELY 10% OF REPRODUCTIVE-AGED WOMEN AND IS DEFINED AS THE PRESENCE OF ENDOMETRIAL GLANDS AND STROMA OUTSIDE THE UTERINE CAVITY. ENDOMETRIOSIS CAN CAUSE A VARIETY OF HEALTH PROBLEMS, FROM PELVIC DISCOMFORT TO CATAMENIAL PNEUMOTHORAX, BUT IT'S MAINLY LINKED WITH SEVERE AND CHRONIC PELVIC PAIN, DYSMENORRHEA, AND DEEP DYSPAREUNIA, AS WELL AS REPRODUCTIVE ISSUES. THE PATHOGENESIS OF ENDOMETRIOSIS INVOLVES AN ENDOCRINE DYSFUNCTION, WITH ESTROGEN DEPENDENCY AND PROGESTERONE RESISTANCE, AND INFLAMMATORY MECHANISM ACTIVATION, TOGETHER WITH IMPAIRED CELL PROLIFERATION AND NEUROANGIOGENESIS. THE PRESENT CHAPTER AIMS TO DISCUSS THE MAIN EPIGENETIC MECHANISMS RELATED TO ESTROGEN RECEPTORS (ERS) AND PROGESTERONE RECEPTORS (PRS) IN PATIENTS WITH ENDOMETRIOSIS. THERE ARE NUMEROUS EPIGENETIC MECHANISMS PARTICIPATING IN ENDOMETRIOSIS, REGULATING THE EXPRESSION OF THE GENES ENCODING THESE RECEPTORS BOTH INDIRECTLY, THROUGH THE REGULATION OF TRANSCRIPTION FACTORS, AND DIRECTLY, THROUGH DNA METHYLATION, HISTONE MODIFICATIONS, MICRO RNAS AND LONG NONCODING RNAS. THIS REPRESENTS AN OPEN FIELD OF INVESTIGATION, WHICH MAY LEAD TO IMPORTANT CLINICAL IMPLICATIONS SUCH AS THE DEVELOPMENT OF EPIGENETIC DRUGS FOR THE TREATMENT OF ENDOMETRIOSIS AND THE IDENTIFICATION OF SPECIFIC AND EARLY BIOMARKERS FOR THE DISEASE. 2023 3 4310 37 MICRORNAS AND PROGESTERONE RECEPTOR SIGNALING IN ENDOMETRIOSIS PATHOPHYSIOLOGY. ENDOMETRIOSIS IS A SIGNIFICANT DISEASE CHARACTERIZED BY INFERTILITY AND PELVIC PAIN IN WHICH ENDOMETRIAL STROMAL AND GLANDULAR TISSUE GROW IN ECTOPIC LOCATIONS. ALTERED RESPONSIVENESS TO PROGESTERONE IS A CONTRIBUTING FACTOR TO ENDOMETRIOSIS PATHOPHYSIOLOGY, BUT THE PRECISE MECHANISMS ARE POORLY UNDERSTOOD. PROGESTERONE RESISTANCE INFLUENCES BOTH THE EUTOPIC AND ECTOPIC (ENDOMETRIOTIC LESION) ENDOMETRIUM. AN INABILITY OF THE EUTOPIC ENDOMETRIUM TO PROPERLY RESPOND TO PROGESTERONE IS BELIEVED TO CONTRIBUTE TO THE INFERTILITY ASSOCIATED WITH THE DISEASE, WHILE AN ALTERED RESPONSIVENESS OF ENDOMETRIOTIC LESION TISSUE MAY CONTRIBUTE TO THE SURVIVAL OF THE ECTOPIC TISSUE AND ASSOCIATED SYMPTOMS. WOMEN WITH ENDOMETRIOSIS EXPRESS ALTERED LEVELS OF SEVERAL ENDOMETRIAL PROGESTERONE TARGET GENES WHICH MAY BE DUE TO THE ABNORMAL EXPRESSION AND/OR FUNCTION OF PROGESTERONE RECEPTORS AND/OR CHAPERONE PROTEINS, AS WELL AS INFLAMMATION, GENETICS, AND EPIGENETICS. MIRNAS ARE A CLASS OF EPIGENETIC MODULATORS PROPOSED TO PLAY A ROLE IN ENDOMETRIOSIS PATHOPHYSIOLOGY, INCLUDING THE MODULATION OF PROGESTERONE SIGNALING. IN THIS PAPER, WE SUMMARIZE THE ROLE OF PROGESTERONE RECEPTORS AND PROGESTERONE SIGNALING IN ENDOMETRIOSIS PATHOPHYSIOLOGY, REVIEW MIRNAS, WHICH ARE OVER-EXPRESSED IN ENDOMETRIOSIS TISSUES AND FLUIDS, AND FOLLOW THIS WITH A DISCUSSION ON THE POTENTIAL REGULATION OF KEY PROGESTERONE SIGNALING COMPONENTS BY THESE MIRNAS, CONCLUDING WITH SUGGESTIONS FOR FUTURE RESEARCH ENDEAVORS IN THIS AREA. 2022 4 2668 29 ESTROGEN RECEPTORS AND ENDOMETRIOSIS. ENDOMETRIOSIS IS A FREQUENT AND CHRONIC INFLAMMATORY DISEASE WITH IMPACTS ON REPRODUCTION, HEALTH AND QUALITY OF LIFE. THIS DISORDER IS HIGHLY ESTROGEN-DEPENDENT AND THE PURPOSE OF HORMONAL TREATMENTS IS TO DECREASE THE ENDOGENOUS OVARIAN PRODUCTION OF ESTROGENS. HIGH ESTROGEN PRODUCTION IS A CONSISTENTLY OBSERVED ENDOCRINE FEATURE OF ENDOMETRIOSIS. MRNA AND PROTEIN LEVELS OF ESTROGEN RECEPTORS (ER) ARE DIFFERENT BETWEEN A NORMAL HEALTHY ENDOMETRIUM AND ECTOPIC/EUTOPIC ENDOMETRIAL LESIONS: ENDOMETRIOTIC STROMAL CELLS EXPRESS EXTRAORDINARILY HIGHER ERBETA AND SIGNIFICANTLY LOWER ERALPHA LEVELS COMPARED WITH ENDOMETRIAL STROMAL CELLS. ABERRANT EPIGENETIC REGULATION SUCH AS DNA METHYLATION IN ENDOMETRIOTIC CELLS IS ASSOCIATED WITH THE PATHOGENESIS AND DEVELOPMENT OF ENDOMETRIOSIS. ALTHOUGH THERE IS A LARGE BODY OF DATA REGARDING ERS IN ENDOMETRIOSIS, OUR UNDERSTANDING OF THE ROLES OF ERALPHA AND ERBETA IN THE PATHOGENESIS OF ENDOMETRIOSIS REMAINS INCOMPLETE. THE GOAL OF THIS REVIEW IS TO PROVIDE AN OVERVIEW OF THE LINKS BETWEEN ENDOMETRIOSIS, ERS AND THE RECENT ADVANCES OF TREATMENT STRATEGIES BASED ON ERS MODULATION. WE WILL ALSO ATTEMPT TO SUMMARIZE THE CURRENT UNDERSTANDING OF THE MOLECULAR AND CELLULAR MECHANISMS OF ACTION OF ERS AND HOW THIS COULD PAVE THE WAY TO NEW THERAPEUTIC STRATEGIES. 2020 5 4129 25 MECHANISMS OF ENDOMETRIAL PROGESTERONE RESISTANCE. THROUGHOUT THE REPRODUCTIVE YEARS, THE RISE AND FALL IN OVARIAN HORMONES ELICIT IN THE ENDOMETRIUM WAVES OF CELL PROLIFERATION, DIFFERENTIATION, RECRUITMENT OF INFLAMMATORY CELLS, APOPTOSIS, TISSUE BREAKDOWN AND REGENERATION. THE ACTIVATED PROGESTERONE RECEPTOR, A MEMBER OF THE SUPERFAMILY OF LIGAND-DEPENDENT TRANSCRIPTION FACTORS, IS THE MASTER REGULATOR OF THIS INTENSE TISSUE REMODELLING PROCESS IN THE UTERUS. ITS ACTIVITY IS TIGHTLY REGULATED BY INTERACTION WITH CELL-SPECIFIC TRANSCRIPTION FACTORS AND COREGULATORS AS WELL AS BY SPECIFIC POSTTRANSLATIONAL MODIFICATIONS THAT RESPOND DYNAMICALLY TO A VARIETY OF ENVIRONMENTAL AND INFLAMMATORY SIGNALS. ENDOMETRIOSIS, A CHRONIC INFLAMMATORY DISORDER, DISRUPTS COORDINATED PROGESTERONE RESPONSES THROUGHOUT THE REPRODUCTIVE TRACT, INCLUDING IN THE ENDOMETRIUM. THIS PHENOMENON IS INCREASINGLY REFERRED TO AS 'PROGESTERONE RESISTANCE'. EMERGING EVIDENCE SUGGESTS THAT PROGESTERONE RESISTANCE IN ENDOMETRIOSIS IS NOT JUST A CONSEQUENCE OF PERTURBED PROGESTERONE SIGNAL TRANSDUCTION CAUSED BY CHRONIC INFLAMMATION BUT ASSOCIATED WITH EPIGENETIC CHROMATIN CHANGES THAT DETERMINE THE INTRINSIC RESPONSIVENESS OF ENDOMETRIAL CELLS TO DIFFERENTIATION CUES. 2012 6 5241 30 PROGESTERONE RESISTANCE IN ENDOMETRIOSIS: CURRENT EVIDENCE AND PUTATIVE MECHANISMS. ENDOMETRIOSIS IS AN ESTROGEN-DEPENDENT DISEASE CHARACTERIZED BY THE GROWTH OF ENDOMETRIAL-LIKE TISSUE OUTSIDE THE UTERUS. PROGESTINS ARE CURRENTLY THE MOST COMMONLY USED TREATMENT FOR ENDOMETRIOSIS BECAUSE OF THEIR EXCELLENT THERAPEUTIC EFFECTS AND LIMITED SIDE EFFECTS. HOWEVER, PROGESTINS HAVE BEEN UNSUCCESSFUL IN SOME SYMPTOMATIC PATIENTS. THE INABILITY OF THE ENDOMETRIUM TO RESPOND PROPERLY TO PROGESTERONE IS KNOWN AS PROGESTERONE RESISTANCE. AN INCREASING BODY OF EVIDENCE SUGGESTS THE LOSS OF PROGESTERONE SIGNALING AND THE EXISTENCE OF PROGESTERONE RESISTANCE IN ENDOMETRIOSIS. THE MECHANISMS OF PROGESTERONE RESISTANCE HAVE RECEIVED CONSIDERABLE SCHOLARLY ATTENTION IN RECENT YEARS. ABNORMAL PGR SIGNALING, CHRONIC INFLAMMATION, ABERRANT GENE EXPRESSION, EPIGENETIC ALTERATIONS, AND ENVIRONMENTAL TOXINS ARE CONSIDERED POTENTIAL MOLECULAR CAUSES OF PROGESTERONE RESISTANCE IN ENDOMETRIOSIS. THE GENERAL OBJECTIVE OF THIS REVIEW WAS TO SUMMARIZE THE EVIDENCE AND MECHANISMS OF PROGESTERONE RESISTANCE. A DEEPER UNDERSTANDING OF HOW THESE MECHANISMS CONTRIBUTE TO PROGESTERONE RESISTANCE MAY HELP DEVELOP A NOVEL THERAPEUTIC REGIMEN FOR WOMEN WITH ENDOMETRIOSIS BY REVERSING PROGESTERONE RESISTANCE. 2023 7 2086 33 EPIGENETIC DYSREGULATION IN ENDOMETRIOSIS: IMPLICATIONS FOR PATHOPHYSIOLOGY AND THERAPEUTICS. ENDOMETRIOSIS IS A PREVALENT GYNECOLOGICAL CONDITION ASSOCIATED WITH PELVIC PAIN AND INFERTILITY. DESPITE MORE THAN A CENTURY OF RESEARCH, THE ETIOLOGY OF ENDOMETRIOSIS STILL ELUDES SCIENTIFIC CONSENSUS. THIS LACK OF CLARITY HAS RESULTED IN SUBOPTIMAL PREVENTION, DIAGNOSIS, AND TREATMENT OPTIONS. EVIDENCE OF GENETIC CONTRIBUTORS TO ENDOMETRIOSIS IS INTERESTING BUT LIMITED; HOWEVER, SIGNIFICANT PROGRESS HAS BEEN MADE IN RECENT YEARS IN IDENTIFYING EPIGENETIC ROLE IN THE PATHOGENESIS OF ENDOMETRIOSIS THROUGH CLINICAL STUDIES, IN VITRO CELL CULTURE EXPERIMENTS, AND IN VIVO ANIMAL MODELS. THE PREDOMINANT FINDINGS INCLUDE ENDOMETRIOSIS-RELATED DIFFERENTIAL EXPRESSION OF DNA METHYLTRANSFERASES AND DEMETHYLASES, HISTONE DEACETYLASES, METHYLTRANSFERASES, AND DEMETHYLASES, AND REGULATORS OF CHROMATIN ARCHITECTURE. THERE IS ALSO AN EMERGING ROLE FOR MIRNAS IN THE CONTROL OF EPIGENETIC REGULATORS IN THE ENDOMETRIUM AND ENDOMETRIOSIS. CHANGES IN THESE EPIGENETIC REGULATORS RESULT IN DIFFERENTIAL CHROMATIN ORGANIZATION AND DNA METHYLATION WITH CONSEQUENCES FOR GENE EXPRESSION INDEPENDENT OF A GENETIC SEQUENCE. EPIGENETICALLY ALTERED EXPRESSION OF GENES RELATED TO STEROID HORMONE PRODUCTION AND SIGNALING, IMMUNE REGULATION, AND ENDOMETRIAL CELL IDENTITY AND FUNCTION HAVE ALL BEEN IDENTIFIED AND APPEAR TO PLAY INTO THE PATHOPHYSIOLOGICAL MECHANISMS OF ENDOMETRIOSIS AS WELL AS RESULTING INFERTILITY. THIS REVIEW SUMMARIZES AND CRITICALLY DISCUSSES EARLY SEMINAL FINDINGS, THE EVER-GROWING RECENT EVIDENCE OF EPIGENETIC CONTRIBUTIONS TO THE PATHOPHYSIOLOGY OF ENDOMETRIOSIS, AND IMPLICATIONS FOR PROPOSED EPIGENETICALLY TARGETED THERAPEUTICS. 2023 8 3005 29 GENETIC, EPIGENETIC, AND STEROIDOGENIC MODULATION MECHANISMS IN ENDOMETRIOSIS. ENDOMETRIOSIS IS A CHRONIC GYNECOLOGICAL DISEASE, AFFECTING UP TO 10% OF REPRODUCTIVE-AGE WOMEN. THE EXACT CAUSE OF THE DISEASE IS UNKNOWN; HOWEVER, IT IS A HERITABLE CONDITION AFFECTED BY MULTIPLE GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS. PREVIOUS STUDIES REPORTED VARIATIONS IN THE EPIGENETIC PATTERNS OF NUMEROUS GENES KNOWN TO BE INVOLVED IN THE ABERRANT MODULATION OF CELL CYCLE STEROIDOGENESIS, ABNORMAL HORMONAL, IMMUNE AND INFLAMMATORY STATUS IN ENDOMETRIOSIS, APOPTOSIS, ADHESION, ANGIOGENESIS, PROLIFERATION, IMMUNE AND INFLAMMATORY PROCESSES, RESPONSE TO HYPOXIA, STEROIDOGENIC PATHWAY AND HORMONE SIGNALING ARE INVOLVED IN THE PATHOGENESIS OF ENDOMETRIOSIS. ACCUMULATING EVIDENCE SUGGEST THAT VARIOUS EPIGENETIC ABERRATIONS MAY CONTRIBUTE TO THE PATHOGENESIS OF ENDOMETRIOSIS. AMONG THEM, DNA METHYLTRANSFERASES, HISTONE DEACETYLATORS, AND NON-CODING MICRORNAS DEMONSTRATE DIFFERENTIAL EXPRESSION WITHIN ENDOMETRIOTIC LESIONS AND IN THE ENDOMETRIUM OF PATIENTS WITH ENDOMETRIOSIS. IT HAS BEEN INDICATED THAT THE IDENTIFICATION OF EPIGENETIC DIFFERENCES WITHIN THE DNA OR HISTONE PROTEINS MAY CONTRIBUTE TO THE DISCOVERY OF A USEFUL PROGNOSTIC BIOMARKER, WHICH COULD AID IN THE FUTURE EARLIER DETECTION, TIMELY DIAGNOSIS, AND INITIATION OF A NEW APPROACH TO THE TREATMENT OF ENDOMETRIOSIS, AS WELL AS INFORM US ABOUT THE EFFECTIVENESS OF TREATMENT AND THE STAGE OF THE DISEASE. AS THE ETIOLOGY OF ENDOMETRIOSIS IS HIGHLY COMPLEX AND STILL FAR FROM BEING FULLY ELUCIDATED, THE PRESENTED REVIEW FOCUSES ON DIFFERENT APPROACHES TO IDENTIFY THE GENETIC AND EPIGENETIC LINKS OF ENDOMETRIOSIS AND ITS PATHOGENESIS. 2020 9 6796 30 [ENDOMETRIOSIS: A NEW APPROACH TO ETIOLOGY AND PATHOGENESIS (REVIEW)]. ENDOMETRIOSIS IS A DYSHORMONAL IMMUNE-DEPENDENT GENETICALLY DETERMINED DISEASE, WHICH APPEARS AS AN ENDOMETRIOID TISSUE THAT GROWS OUTSIDE THE UTERINE. ENDOMETRIOSIS IS ONE OF THE MOST URGENT PROBLEMS OF MEDICINE. TO DATE, NEW CONCEPTS OF THE ENDOMETRIOSIS ETIOLOGY AND PATHOGENESIS HAVE BEEN DEVELOPED, BUT, DESPITE THEIR ABUNDANCE, THERE IS NO UNIFIED THEORY. GENETIC AND EPIGENETIC FACTORS RESULT IN CHANGES IN AN EXPRESSION OF AROMATASE, STEROIDOGENIC FACTOR 1, AND ESTROGEN RECEPTORS ARE SUGGESTED TO BE THE MAIN CAUSE OF ENDOMETRIOSIS. THESE CHANGES LEAD TO AN ACTIVE SYNTHESIS OF VARIOUS PRO-INFLAMMATORY AGENTS AND A NERVE GROWTH FACTOR, THAT ARE IMPORTANT IN THE DEVELOPMENT OF PAIN SYNDROME. ALSO, CHANGES IN THE PROGESTERONE RECEPTOR FUNCTIONING AND THE LOCAL PROGESTERONE RESISTANCE DEVELOPMENT DECREASE THE ANTIPROLIFERATIVE ACTIVITY, APOPTOSIS, AND THE ANTI-INFLAMMATORY SUBSTANCES LEVEL, AS WELL AS INCREASE THE PROSTAGLANDIN, METALLOPROTEINASE ACTIVITY, AND LEVEL OF HYPOXIA FACTORS. IN ADDITION, THERE ARE SHREDS OF EVIDENCE THAT ENDOMETRIOSIS IS ASSOCIATED WITH THE RISK OF MALIGNANT TUMORS DEVELOPMENT, SO NEW CONCEPTS FOR UNDERSTANDING THESE MECHANISMS ARE ACTIVELY DEVELOPING. SOME OF THESE MECHANISMS ARE DISCUSSED IN THIS REVIEW. 2017 10 5892 32 SYSTEMS GENETICS VIEW OF ENDOMETRIOSIS: A COMMON COMPLEX DISORDER. ENDOMETRIOSIS IS A CONDITION IN WHICH CELLS DERIVED FROM THE ENDOMETRIUM GROW OUTSIDE THE UTERUS, E.G. IN THE PERITONEUM (EXTERNAL GENITAL ENDOMETRIOSIS). AS THESE CELLS ARE UNDER THE INFLUENCE OF FEMALE HORMONES, MAJOR SYMPTOMS OF ENDOMETRIOSIS ARE PAIN, ESPECIALLY DURING THE CYCLE, AND INFERTILITY. NUMEROUS HYPOTHESES FOR THE FORMATION OF ENDOMETRIOSIS CAN BE FOUND IN THE LITERATURE, BUT THERE IS GROWING EVIDENCE OF SERIOUS GENETIC CONTRIBUTIONS TO ENDOMETRIOSIS SUSCEPTIBILITY. THE INVOLVEMENT OF GENES, STEROID HORMONE METABOLISM, IMMUNOLOGICAL REACTIONS, RECEPTOR FORMATION, INFLAMMATION, PROLIFERATION, APOPTOSIS, INTERCELLULAR ADHESION, CELL INVASION AND ANGIOGENESIS AS WELL AS GENES REGULATING THE ACTIVITY OF AFOREMENTIONED ENZYMES HAVE BEEN SUGGESTED. SOME MORE RECENTLY SUGGESTED CANDIDATE GENES PICKED UP IN GENOME-WIDE ASSOCIATION STUDIES ARE INVOLVED IN ONCOGENESIS, METAPLASIA OF ENDOMETRIUM CELLS AND PATHWAYS OF EMBRYONIC DEVELOPMENT OF THE FEMALE REPRODUCTIVE SYSTEM. HOWEVER, GENE MUTATIONS PROVEN TO BE CAUSATIVE FOR ENDOMETRIOSIS HAVE NOT BEEN IDENTIFIED SO FAR, EVEN THOUGH THE ABNORMAL EXPRESSION OF CANDIDATE GENES FOR ENDOMETRIOSIS COULD BE PROVOKED BY DIFFERENT EPIGENETIC MODIFICATIONS INCLUDING DNA METHYLATION, HETEROCHROMATIZATION OR INTRODUCTION OF REGULATORY MIRNA. WE HYPOTHESIZE THAT ENDOMETRIOSIS IS INDUCED BY A COMBINATION OF ABNORMAL GENETIC AND/OR EPIGENETIC MUTATIONS: THE LATTER PAVE THE WAY FOR PATHOLOGICAL CHANGES WHICH BECOME IRREVERSIBLE, AND ACCORDING TO THE "EPIGENETIC LANDSCAPE" THEORY, THIS PROCEEDS TO THE TYPICAL CLINICAL MANIFESTATIONS. TWO STAGES IN THE ENDOMETRIOSIS PATHWAY ARE SUGGESTED: (1) INDUCTION OF PRIMARY ENDOMETRIAL CELLS TOWARD ENDOMETRIOSIS, AND (2) IMPLANTATION AND PROGRESSION OF THESE CELLS INTO ENDOMETRIOSIS LESIONS. THE MODEL FAVORS ENDOMETRIOSIS AS AN OUTGROWTH OF PRIMARY CELLS DIFFERENT IN THEIR ORIGIN, CANALIZATION OF PATHOLOGICAL PROCESSES, MANIFESTATION DIVERSITY PROVOKED BY UNIQUE GENETIC BACKGROUND AND EPIGENETIC INFLUENCES, WHICH RESULT IN MANY DIFFERENT CLINICAL FORMS OF THE DISEASE. 2015 11 3003 31 GENETIC, EPIGENETIC AND STEM CELL ALTERATIONS IN ENDOMETRIOSIS: NEW INSIGHTS AND POTENTIAL THERAPEUTIC PERSPECTIVES. HUMAN ENDOMETRIUM IS A HIGHLY DYNAMIC TISSUE, UNDERGOING PERIODIC GROWTH AND REGRESSION AT EACH MENSTRUAL CYCLE. ENDOMETRIOSIS IS A FREQUENT CHRONIC PATHOLOGICAL STATUS CHARACTERIZED BY ENDOMETRIAL TISSUE WITH AN ECTOPIC LOCALIZATION, CAUSING PELVIC PAIN AND INFERTILITY AND A VARIABLE CLINICAL PRESENTATION. IN ADDITION, THERE IS WELL-ESTABLISHED EVIDENCE THAT, ALTHOUGH ENDOMETRIOSIS IS CONSIDERED BENIGN, IT IS ASSOCIATED WITH AN INCREASED RISK OF MALIGNANT TRANSFORMATION IN APPROXIMATELY 1.0% OF AFFECTED WOMEN, WITH THE INVOLVEMENT OF MULTIPLE PATHWAYS OF DEVELOPMENT. INCREASING EVIDENCE SUPPORTS A KEY CONTRIBUTION OF DIFFERENT STEM/PROGENITOR CELL POPULATIONS NOT ONLY IN THE CYCLIC REGENERATION OF EUTOPIC ENDOMETRIUM, BUT ALSO IN THE PATHOGENESIS OF AT LEAST SOME TYPES OF ENDOMETRIOSIS. EVIDENCE HAS ARISEN FROM EXPERIMENTS IN ANIMAL MODELS OF DISEASE THROUGH DIFFERENT KINDS OF ASSAYS (INCLUDING CLONOGENICITY, THE LABEL-RETAINING CELL APPROACH, THE ANALYSIS OF UNDIFFERENTIATION MARKERS), AS WELL AS FROM DESCRIPTIVE STUDIES ON ECTOPIC AND EUTOPIC TISSUE SAMPLES HARVESTED FROM AFFECTED WOMEN. CHANGES IN STEM CELL POPULATIONS IN ENDOMETRIOTIC LESIONS ARE ASSOCIATED WITH GENETIC AND EPIGENETIC ALTERATIONS, INCLUDING IMBALANCE OF MIRNA EXPRESSION, HISTONE AND DNA MODIFICATIONS AND CHROMOSOMAL ABERRATIONS. THE PRESENT SHORT REVIEW MAINLY SUMMARIZES THE LATEST OBSERVATIONS CONTRIBUTING TO THE CURRENT KNOWLEDGE REGARDING THE PRESENCE AND THE POTENTIAL CONTRIBUTION OF STEM/PROGENITOR CELLS IN EUTOPIC ENDOMETRIUM AND THE AETIOLOGY OF ENDOMETRIOSIS, TOGETHER WITH A REPORT OF THE MOST RECENTLY IDENTIFIED GENETIC AND EPIGENETIC ALTERATIONS IN ENDOMETRIOSIS. WE ALSO DESCRIBE THE POTENTIAL ADVANTAGES OF SINGLE CELL MOLECULAR PROFILING IN ENDOMETRIUM AND IN ENDOMETRIOTIC LESIONS. ALL THESE DATA CAN HAVE CLINICAL IMPLICATIONS AND PROVIDE A BASIS FOR NEW POTENTIAL THERAPEUTIC APPLICATIONS. 2014 12 1891 34 ENDOMETRIOSIS. PELVIC ENDOMETRIOSIS IS A COMPLEX SYNDROME CHARACTERIZED BY AN ESTROGEN-DEPENDENT CHRONIC INFLAMMATORY PROCESS THAT AFFECTS PRIMARILY PELVIC TISSUES, INCLUDING THE OVARIES. IT IS CAUSED WHEN SHED ENDOMETRIAL TISSUE TRAVELS RETROGRADE INTO THE LOWER ABDOMINAL CAVITY. ENDOMETRIOSIS IS THE MOST COMMON CAUSE OF CHRONIC PELVIC PAIN IN WOMEN AND IS ASSOCIATED WITH INFERTILITY. THE UNDERLYING PATHOLOGIC MECHANISMS IN THE INTRACAVITARY ENDOMETRIUM AND EXTRAUTERINE ENDOMETRIOTIC TISSUE INVOLVE DEFECTIVELY PROGRAMMED ENDOMETRIAL MESENCHYMAL PROGENITOR/STEM CELLS. ALTHOUGH ENDOMETRIOTIC STROMAL CELLS, WHICH COMPOSE THE BULK OF ENDOMETRIOTIC LESIONS, DO NOT CARRY SOMATIC MUTATIONS, THEY DEMONSTRATE SPECIFIC EPIGENETIC ABNORMALITIES THAT ALTER EXPRESSION OF KEY TRANSCRIPTION FACTORS. FOR EXAMPLE, GATA-BINDING FACTOR-6 OVEREXPRESSION TRANSFORMS AN ENDOMETRIAL STROMAL CELL TO AN ENDOMETRIOTIC PHENOTYPE, AND STEROIDOGENIC FACTOR-1 OVEREXPRESSION CAUSES EXCESSIVE PRODUCTION OF ESTROGEN, WHICH DRIVES INFLAMMATION VIA PATHOLOGICALLY HIGH LEVELS OF ESTROGEN RECEPTOR-BETA. PROGESTERONE RECEPTOR DEFICIENCY CAUSES PROGESTERONE RESISTANCE. POPULATIONS OF ENDOMETRIAL AND ENDOMETRIOTIC EPITHELIAL CELLS ALSO HARBOR MULTIPLE CANCER DRIVER MUTATIONS, SUCH AS KRAS, WHICH MAY BE ASSOCIATED WITH THE ESTABLISHMENT OF PELVIC ENDOMETRIOSIS OR OVARIAN CANCER. IT IS NOT KNOWN HOW INTERACTIONS BETWEEN EPIGENOMICALLY DEFECTIVE STROMAL CELLS AND THE MUTATED GENES IN EPITHELIAL CELLS CONTRIBUTE TO THE PATHOGENESIS OF ENDOMETRIOSIS. ENDOMETRIOSIS-ASSOCIATED PELVIC PAIN IS MANAGED BY SUPPRESSION OF OVULATORY MENSES AND ESTROGEN PRODUCTION, CYCLOOXYGENASE INHIBITORS, AND SURGICAL REMOVAL OF PELVIC LESIONS, AND IN VITRO FERTILIZATION IS FREQUENTLY USED TO OVERCOME INFERTILITY. ALTHOUGH NOVEL TARGETED TREATMENTS ARE BECOMING AVAILABLE, AS ENDOMETRIOSIS PATHOPHYSIOLOGY IS BETTER UNDERSTOOD, PREVENTIVE APPROACHES SUCH AS LONG-TERM OVULATION SUPPRESSION MAY PLAY A CRITICAL ROLE IN THE FUTURE. 2019 13 2275 41 EPIGENETIC REGULATION AND T-CELL RESPONSES IN ENDOMETRIOSIS - SOMETHING OTHER THAN AUTOIMMUNITY. ENDOMETRIOSIS IS DEFINED AS THE PRESENCE OF ENDOMETRIAL-LIKE GLANDS AND STROMA LOCATED OUTSIDE THE UTERINE CAVITY. THIS COMMON, ESTROGEN DEPENDENT, INFLAMMATORY CONDITION AFFECTS UP TO 15% OF REPRODUCTIVE-AGED WOMEN AND IS A WELL-RECOGNIZED CAUSE OF CHRONIC PELVIC PAIN AND INFERTILITY. DESPITE THE STILL UNKNOWN ETIOLOGY OF ENDOMETRIOSIS, MUCH EVIDENCE SUGGESTS THE PARTICIPATION OF EPIGENETIC MECHANISMS IN THE DISEASE ETIOPATHOGENESIS. THE MAIN RATIONALE IS BASED ON THE FACT THAT HERITABLE PHENOTYPE CHANGES THAT DO NOT INVOLVE ALTERATIONS IN THE DNA SEQUENCE ARE COMMON TRIGGERS FOR HORMONAL, IMMUNOLOGICAL, AND INFLAMMATORY DISORDERS, WHICH PLAY A KEY ROLE IN THE FORMATION OF ENDOMETRIOTIC FOCI. EPIGENETIC MECHANISMS REGULATING T-CELL RESPONSES, INCLUDING DNA METHYLATION AND POSTTRANSLATIONAL HISTONE MODIFICATIONS, DESERVE ATTENTION BECAUSE TISSUE-RESIDENT T LYMPHOCYTES WORK IN CONCERT WITH ORGAN STRUCTURAL CELLS TO GENERATE APPROPRIATE IMMUNE RESPONSES AND ARE FUNCTIONALLY SHAPED BY ORGAN-SPECIFIC ENVIRONMENTAL CONDITIONS. THUS, A FAILURE TO PRECISELY REGULATE IMMUNE CELL TRANSCRIPTION MAY RESULT IN COMPROMISED IMMUNOLOGICAL INTEGRITY OF THE ORGAN WITH AN INCREASED RISK OF INFLAMMATORY DISORDERS. THE COEXISTENCE OF ENDOMETRIOSIS AND AUTOIMMUNITY IS A WELL-KNOWN OCCURRENCE. RECENT RESEARCH RESULTS INDICATE REGULATORY T-CELL (TREG) ALTERATIONS IN ENDOMETRIOSIS, AND AN INCREASED NUMBER OF HIGHLY ACTIVE TREGS AND MACROPHAGES HAVE BEEN FOUND IN PERITONEAL FLUID FROM WOMEN WITH ENDOMETRIOSIS. ELIMINATION OF THE REGULATORY FUNCTION OF T CELLS AND AN IMBALANCE BETWEEN T HELPER CELLS OF THE TH1 AND TH2 TYPES HAVE BEEN REPORTED IN THE ENDOMETRIA OF WOMEN WITH ENDOMETRIOSIS-ASSOCIATED INFERTILITY. THIS REVIEW AIMS TO PRESENT THE STATE OF THE ART IN RECOGNITION EPIGENETIC REPROGRAMMING OF T CELLS AS THE KEY FACTOR IN THE PATHOPHYSIOLOGY OF ENDOMETRIOSIS IN THE CONTEXT OF T-CELL-RELATED AUTOIMMUNITY. THE NEW POTENTIAL THERAPEUTIC APPROACHES BASED ON EPIGENETIC MODULATION AND/OR ADOPTIVE TRANSFER OF T CELLS WILL ALSO BE OUTLINED. 2022 14 1202 37 COULD DNA HYDROXYMETHYLATION BE CRUCIAL IN INFLUENCING STEROID HORMONE SIGNALING IN ENDOMETRIAL BIOLOGY AND ENDOMETRIOSIS? ENDOMETRIOSIS AFFECTS 10% OF REPRODUCTIVE-AGED WOMEN. IT IS CHARACTERIZED BY THE GROWTH OF THE ENDOMETRIUM, OUTSIDE THE UTERUS AND IS ASSOCIATED WITH INFERTILITY AND CHRONIC ABDOMINAL PAIN. LACK OF NONINVASIVE DIAGNOSTIC TOOLS AND EARLY SCREENING TESTS RESULTS IN DELAYED TREATMENT AND SUBSEQUENTLY INCREASED DISEASE SEVERITY. ENDOMETRIOSIS IS A DISEASE ASSOCIATED WITH A DEREGULATED HORMONAL RESPONSE, THEREFORE, UNDERSTANDING THE MOLECULAR MECHANISMS THAT GOVERN THIS HORMONAL INTERPLAY IS OF PARAMOUNT IMPORTANCE. DNA METHYLATION IS AN EPIGENETIC MARK THAT REGULATES GENE EXPRESSION AND IS OFTEN ASSOCIATED WITH GENES THAT CODE FOR STEROID RECEPTORS AND ENZYMES ASSOCIATED WITH ESTROGEN SYNTHESIS AND METABOLISM IN ENDOMETRIOSIS. DNA HYDROXYMETHYLATION, WHICH IS STRUCTURALLY SIMILAR TO METHYLATION BUT FUNCTIONALLY DIFFERENT, IS A BIOLOGICALLY CRITICAL MECHANISM THAT IS ALSO KNOWN TO REGULATE GENE EXPRESSION. TEN ELEVEN TRANSLOCATION (TET) PROTEINS MEDIATE HYDROXYMETHYLATION. HOWEVER, THE ROLE OF DNA HYDROXYMETHYLATION OR TETS IN THE ENDOMETRIUM REMAINS RELATIVELY UNEXPLORED. CURRENTLY, THE "GOLD STANDARD" TECHNIQUE USED TO STUDY METHYLATION PATTERNS IS BISULFITE GENOMIC SEQUENCING. THIS TECHNIQUE ALSO DETECTS HYDROXYMETHYLATION BUT FAILS TO DISTINGUISH BETWEEN THE TWO, THEREBY LIMITING OUR UNDERSTANDING OF THESE TWO PROCESSES. THE PRESENCE OF TETS IN THE MALE AND FEMALE REPRODUCTIVE TRACT AND ITS CONTRIBUTION TO ENDOMETRIAL CANCER MAKES IT AN IMPORTANT FACTOR TO STUDY IN ENDOMETRIOSIS. THIS REVIEW SUMMARIZES THE ROLE OF DNA METHYLATION IN ABERRANT STEROID HORMONE SIGNALING AND HYPOTHESIZES THAT HYDROXYMETHYLATION COULD BE A FACTOR INFLUENCING HORMONAL INSTABILITY SEEN IN ENDOMETRIOSIS. 2020 15 5378 23 RECENT INSIGHTS ON THE GENETICS AND EPIGENETICS OF ENDOMETRIOSIS. ENDOMETRIOSIS IS A GYNECOLOGIC DISEASE AFFECTING UP TO 10% OF THE WOMEN AND A MAJOR CAUSE OF PAIN AND INFERTILITY. IT IS CHARACTERIZED BY THE IMPLANTATION OF FUNCTIONAL ENDOMETRIAL TISSUE AT ECTOPIC POSITIONS GENERALLY WITHIN THE PERITONEUM. THIS COMPLEX DISEASE HAS AN IMPORTANT GENETIC COMPONENT WITH A HERITABILITY ESTIMATED AT AROUND 50%. THIS REVIEW AIMS AT PROVIDING RECENT INSIGHTS INTO THE GENETIC BASES OF ENDOMETRIOSIS, AND PRESENTS A DETAILED OVERVIEW OF EVIDENCE OF EPIGENETIC ALTERATIONS SPECIFIC TO THIS DISEASE. IN THE FUTURE, THESE ALTERATIONS MAY CONSTITUTE THERAPEUTIC TARGETS FOR PHARMACOLOGICAL COMPOUNDS ABLE TO MODIFY THE EPIGENETIC CODE. 2017 16 6003 33 THE ADAPTIVE IMMUNE SYSTEM IN MULTIPLE SCLEROSIS: AN ESTROGEN-MEDIATED POINT OF VIEW. MULTIPLE SCLEROSIS (MS) IS A CHRONIC CENTRAL NERVOUS SYSTEM INFLAMMATORY DISEASE THAT LEADS TO DEMYELINATION AND NEURODEGENERATION. THE THIRD TRIMESTER OF PREGNANCY, WHICH IS CHARACTERIZED BY HIGH LEVELS OF ESTROGENS, HAS BEEN SHOWN TO BE ASSOCIATED WITH REDUCED RELAPSE RATES COMPARED WITH THE RATES BEFORE PREGNANCY. THESE EFFECTS COULD BE RELATED TO THE ANTI-INFLAMMATORY PROPERTIES OF ESTROGENS, WHICH ORCHESTRATE THE RESHUFFLING OF THE IMMUNE SYSTEM TOWARD IMMUNOTOLERANCE TO ALLOW FOR FETAL GROWTH. THE ACTION OF THESE HORMONES IS MEDIATED BY THE TRANSCRIPTIONAL REGULATION ACTIVITY OF ESTROGEN RECEPTORS (ERS). ESTROGEN LEVELS AND ER EXPRESSION DEFINE A SPECIFIC BALANCE OF IMMUNE CELL TYPES. IN THIS REVIEW, WE EXPLORE THE ROLE OF ESTRADIOL (E2) AND ERS IN THE ADAPTIVE IMMUNE SYSTEM, WITH A FOCUS ON ESTROGEN-MEDIATED CELLULAR, MOLECULAR, AND EPIGENETIC MECHANISMS RELATED TO IMMUNE TOLERANCE AND NEUROPROTECTION IN MS. THE EPIGENOME DYNAMICS OF IMMUNE SYSTEMS ARE DESCRIBED AS KEY MOLECULAR MECHANISMS THAT ACT ON THE REGULATION OF IMMUNE CELL IDENTITY. THIS IS A COMPLETELY UNEXPLORED FIELD, SUGGESTING A FUTURE PATH FOR MORE EXTENSIVE RESEARCH ON ESTROGEN-INDUCED COREGULATORY COMPLEXES AND MOLECULAR CIRCUITRY AS TARGETS FOR THERAPEUTICS IN MS. 2019 17 1028 35 CIRCULATING MIRNAS RELATED TO EPITHELIAL-MESENCHYMAL TRANSITIONS (EMT) AS THE NEW MOLECULAR MARKERS IN ENDOMETRIOSIS. ENDOMETRIOSIS IS A CHRONIC GYNECOLOGICAL DISEASE DEFINED BY THE PRESENCE OF ENDOMETRIAL-LIKE TISSUE FOUND OUTSIDE THE UTERUS, MOST COMMONLY IN THE PERITONEAL CAVITY. ENDOMETRIOSIS LESIONS ARE HETEROGENOUS BUT USUALLY CONTAIN ENDOMETRIAL STROMAL CELLS AND EPITHELIAL GLANDS, IMMUNE CELL INFILTRATES AND ARE VASCULARIZED AND INNERVATED BY NERVES. THE COMPLEX ETIOPATHOGENESIS AND HETEROGENITY OF THE CLINICAL SYMPTOMS, AS WELL AS THE LACK OF A SPECIFIC NON-INVASIVE DIAGNOSTIC BIOMARKERS, UNDERLINE THE NEED FOR MORE ADVANCED DIAGNOSTIC TOOLS. UNFORTUNATELY, THE CONTRIBUTION OF ENVIRONMENTAL, HORMONAL AND IMMUNOLOGICAL FACTORS IN THE DISEASE ETIOLOGY IS INSUFFICIENT, AND THE CONTRIBUTION OF GENETIC/EPIGENETIC FACTORS IS STILL FRAGMENTARY. THEREFORE, THERE IS A NEED FOR MORE FOCUSED STUDY ON THE MOLECULAR MECHANISMS OF ENDOMETRIOSIS AND NON-INVASIVE DIAGNOSTIC MONITORING SYSTEMS. MICRORNAS (MIRNAS) DEMONSTRATE HIGH STABILITY AND TISSUE SPECIFICITY AND PLAY A SIGNIFICANT ROLE IN MODULATING A RANGE OF MOLECULAR PATHWAYS, AND HENCE MAY BE SUITABLE DIAGNOSTIC BIOMARKERS FOR THE ORIGIN AND DEVELOPMENT OF ENDOMETRIOSIS. OF THESE, THE MOST FREQUENTLY STUDIED ARE THOSE RELATED TO ENDOMETRIOSIS, INCLUDING THOSE INVOLVED IN EPITHELIAL-MESENCHYMAL TRANSITION (EMT), WHOSE EXPRESSION IS ALTERED IN PLASMA OR ENDOMETRIOTIC LESION BIOPSIES; HOWEVER, THE RESULTS ARE AMBIGUOUS. SPECIFIC MIRNAS EXPRESSED IN ENDOMETRIOSIS MAY SERVE AS DIAGNOSTICS MARKERS WITH PROGNOSTIC VALUE, AND THEY HAVE BEEN PROPOSED AS MOLECULAR TARGETS FOR TREATMENT. THE AIM OF THIS REVIEW IS TO PRESENT SELECTED MIRNAS ASSOCIATED WITH EMT KNOWN TO HAVE EXPERIMENTALLY CONFIRMED SIGNIFICANCE, AND DISCUSS THEIR UTILITY AS BIOMARKERS IN ENDOMETRIOSIS. 2021 18 5239 33 PROGESTERONE ALLEVIATES ENDOMETRIOSIS VIA INHIBITION OF UTERINE CELL PROLIFERATION, INFLAMMATION AND ANGIOGENESIS IN AN IMMUNOCOMPETENT MOUSE MODEL. ENDOMETRIOSIS, DEFINED AS GROWTH OF THE ENDOMETRIAL CELLS OUTSIDE THE UTERUS, IS AN INFLAMMATORY DISORDER THAT IS ASSOCIATED WITH CHRONIC PELVIC PAIN AND INFERTILITY IN WOMEN OF CHILDBEARING AGE. ALTHOUGH THE ESTROGEN-DEPENDENCE OF ENDOMETRIOSIS IS WELL KNOWN, THE ROLE OF PROGESTERONE IN DEVELOPMENT OF THIS DISEASE REMAINS POORLY UNDERSTOOD. IN THIS STUDY, WE DEVELOPED A DISEASE MODEL IN WHICH ENDOMETRIOSIS WAS INDUCED IN THE PERITONEAL CAVITIES OF IMMUNOCOMPETENT FEMALE MICE, AND MAINTAINED WITH EXOGENOUS ESTROGEN. THE ENDOMETRIOSIS-LIKE LESIONS THAT WERE IDENTIFIED AT A VARIETY OF ECTOPIC LOCATIONS EXHIBITED ABUNDANT BLOOD SUPPLY AND EXTENSIVE ADHESIONS. HISTOLOGICAL EXAMINATION REVEALED THAT THESE LESIONS HAD A WELL-ORGANIZED ENDOMETRIAL ARCHITECTURE AND FIBROTIC RESPONSE, RESEMBLING THOSE RECOVERED FROM CLINICAL PATIENTS. IN ADDITION, AN EXTENSIVE PROLIFERATION, INFLAMMATORY RESPONSE, AND LOSS OF ESTROGEN RECEPTOR ALPHA (ERALPHA) AND PROGESTERONE RECEPTOR (PR) EXPRESSION WERE ALSO OBSERVED IN THESE LESIONS. INTERESTINGLY, ADMINISTRATION OF PROGESTERONE BEFORE, BUT NOT AFTER, LESION INDUCTION SUPPRESSED LESION EXPANSION AND MAINTAINED ERALPHA AND PR EXPRESSIONS. THESE PROGESTERONE-PRETREATED LESIONS EXHIBITED ATTENUATION IN KI67, CD31, AND PRO-INFLAMMATORY CYTOKINE EXPRESSION AS WELL AS MACROPHAGE INFILTRATION, INDICATING THAT PROGESTERONE AMELIORATES ENDOMETRIOSIS PROGRESSION BY INHIBITING CELL PROLIFERATION, INFLAMMATION AND NEOVASCULARIZATION. OUR STUDIES FURTHER SHOWED THAT SUPPRESSION OF GLOBAL DNA METHYLATION BY APPLICATION OF DNA METHYLTRANSFERASE INHIBITOR TO FEMALE MICE BEARING ECTOPIC LESIONS RESTRAINED LESION EXPANSION AND RESTORED ERALPHA AND PR EXPRESSION IN EUTOPIC ENDOMETRIUM AND ECTOPIC LESIONS. THESE RESULTS INDICATE THAT EPIGENETIC REGULATION OF TARGET GENE EXPRESSION VIA DNA METHYLATION CONTRIBUTES, AT LEAST IN PART, TO PROGESTERONE RESISTANCE IN ENDOMETRIOSIS. 2016 19 1889 27 ENDOMETRIOSIS MALIGNANT TRANSFORMATION: EPIGENETICS AS A PROBABLE MECHANISM IN OVARIAN TUMORIGENESIS. ENDOMETRIOSIS, DEFINED AS THE PRESENCE OF ECTOPIC ENDOMETRIAL GLANDS AND STROMA OUTSIDE THE UTERINE CAVITY, IS A CHRONIC, HORMONE-DEPENDENT GYNECOLOGIC DISEASE AFFECTING MILLIONS OF WOMEN ACROSS THE WORLD, WITH SYMPTOMS INCLUDING CHRONIC PELVIC PAIN, DYSMENORRHEA, DYSPAREUNIA, DYSURIA, AND SUBFERTILITY. IN ADDITION, THERE IS WELL-ESTABLISHED EVIDENCE THAT, ALTHOUGH ENDOMETRIOSIS IS CONSIDERED BENIGN, IT IS ASSOCIATED WITH AN INCREASED RISK OF MALIGNANT TRANSFORMATION, WITH THE INVOLVEMENT OF VARIOUS MECHANISMS OF DEVELOPMENT. MORE AND MORE EVIDENCE REVEALS AN IMPORTANT CONTRIBUTION OF EPIGENETIC MODIFICATION NOT ONLY IN ENDOMETRIOSIS BUT ALSO IN MECHANISMS OF ENDOMETRIOSIS MALIGNANT TRANSFORMATION, INCLUDING DNA METHYLATION AND DEMETHYLATION, HISTONE MODIFICATIONS, AND MIRNA ABERRANT EXPRESSIONS. IN THIS PRESENT REVIEW, WE MAINLY SUMMARIZE THE RESEARCH PROGRESS ABOUT THE CURRENT KNOWLEDGE REGARDING THE EPIGENETIC MODIFICATIONS OF THE RELATIONS BETWEEN ENDOMETRIOSIS MALIGNANT TRANSFORMATION AND OVARIAN CANCER IN AN EFFORT TO IDENTIFY SOME RISK FACTORS PROBABLY ASSOCIATED WITH ECTOPIC ENDOMETRIUM TRANSFORMATION. 2018 20 6272 24 THE ORIGIN AND PATHOGENESIS OF ENDOMETRIOSIS. RECENT MOLECULAR GENETIC FINDINGS ON ENDOMETRIOSIS AND NORMAL ENDOMETRIUM SUGGEST A MODIFIED MODEL IN WHICH CIRCULATING EPITHELIAL PROGENITOR OR STEM CELLS INTENDED TO REGENERATE UTERINE ENDOMETRIUM AFTER MENSTRUATION MAY BECOME OVERREACTIVE AND TRAPPED OUTSIDE THE UTERUS. THESE TRAPPED EPITHELIUM-COMMITTED PROGENITOR CELLS FORM NASCENT GLANDS THROUGH CLONAL EXPANSION AND RECRUIT POLYCLONAL STROMAL CELLS, LEADING TO THE ESTABLISHMENT OF DEEP INFILTRATING ENDOMETRIOSIS. ONCE FORMED, THE ECTOPIC TISSUE BECOMES SUBJECT TO IMMUNE SURVEILLANCE, RESULTING IN CHRONIC INFLAMMATION. THE INFLAMMATORY RESPONSE ORCHESTRATED BY NUCLEAR FACTOR-KAPPAB SIGNALING IS EXACERBATED BY ABERRATIONS IN THE ESTROGEN RECEPTOR-BETA AND PROGESTERONE RECEPTOR PATHWAYS, WHICH ARE ALSO AFFECTED BY LOCAL INFLAMMATION, FORMING A DYSREGULATED INFLAMMATION-HORMONAL LOOP. GLANDULAR EPITHELIUM WITHIN ENDOMETRIOTIC TISSUE HARBORS CANCER-ASSOCIATED MUTATIONS THAT ARE FREQUENTLY DETECTED IN ENDOMETRIOSIS-RELATED OVARIAN CANCERS. IN THIS REVIEW, WE SUMMARIZE RECENT ADVANCES THAT HAVE ILLUMINATED THE ORIGIN AND PATHOGENESIS OF ENDOMETRIOSIS AND HAVE PROVIDED NEW AVENUES FOR RESEARCH THAT PROMISE TO IMPROVE THE EARLY DIAGNOSIS AND MANAGEMENT OF ENDOMETRIOSIS. 2020