Endometriosis-associated Cancer Research Articles

Pathogenesis of Endometriosis and Endometriosis-Associated Cancers.

Endometriosis is a hormone-dependent, chronic inflammatory condition that affects 5-10% of reproductive-aged women. It is a complex disorder characterized by the growth of endometrial-like tissue outside the uterus, which can cause chronic pelvic pain and infertility. Despite its prevalence, the underlying molecular mechanisms of this disease remain poorly understood. Current treatment options are limited and focus mainly on suppressing lesion activity rather than eliminating it entirely. Although endometriosis is generally considered a benign condition, substantial evidence suggests that it increases the risk of developing specific subtypes of ovarian cancer. The discovery of cancer driver mutations in endometriotic lesions indicates that endometriosis may share molecular pathways with cancer. Moreover, the application of single-cell and spatial genomics, along with the development of organoid models, has started to illuminate the molecular mechanisms underlying disease etiology. This review aims to summarize the key genetic mutations and alterations that drive the development and progression of endometriosis to malignancy. We also review the significant recent advances in the understanding of the molecular basis of the disorder, as well as novel approaches and in vitro models that offer new avenues for improving our understanding of disease pathology and for developing new targeted therapies.

Genetic Links between Endometriosis and Endometriosis-Associated Ovarian Cancer-A Narrative Review (Endometriosis-Associated Cancer).

Endometriosis is a frequent, estrogen-dependent, chronic disease, characterized by the presence of endometrial glands and stroma outside of the uterine cavity. Although it is not considered a precursor of cancer, endometriosis is associated with ovarian cancer. In this review, we summarized the evidence that clear-cell and endometrioid ovarian carcinomas (endometriosis-associated ovarian carcinoma-EAOC) may arise in endometriosis. The most frequent genomic alterations in these carcinomas are mutations in the AT-rich interaction domain containing protein 1A (ARID1A) gene, a subunit of the SWI/SNF chromatin remodeling complex, and alterations in phosphatidylinositol 3-kinase (PI3K) which frequently coexist. Recent studies have also suggested the simultaneous role of the PTEN tumor-suppressor gene in the early malignant transformation of endometriosis and the contribution of deficient MMR (mismatch repair) protein status in the pathogenesis of EAOC. In addition to activating and inactivating mutations in cancer driver genes, the complex pathogenesis of EAOC involves multiple other mechanisms such as the modulation of cancer driver genes via the transcriptional and post-translational (miRNA) modulation of cancer driver genes and the interplay with the inflammatory tissue microenvironment. This knowledge is being translated into the clinical management of endometriosis and EAOC. This includes the identification of the new biomarkers predictive of the risk of endometriosis and cancer, and it will shape the precision oncology treatment of EAOC.

Abstract A014: Role of stromal CD10 expression in progression of endometrial and endometriosis-associated cancers

Abstract Endometriosis-associated carcinomas (EACs) and endometrial malignancies have many commonalities yet their pathophysiology, particularly those with high-risk histology such as clear cell, is understudied. EACs are histologically and clinically distinct from other gynecological cancers due to their unique origin within endometriosis. The endometriotic microenvironment is uniquely hypoxic with high levels of iron due to recurrent menstrual cycling, and this iron-rich microenvironment has been linked to promoting carcinogenesis through iron-induced oxidative stress. However, the mechanism by which the endometriotic microenvironment contributes to EAC tumorigenesis and how this compares with endometrial cancer is unknown. Most of our current knowledge of EACs is built on either epidemiologic analyses or correlative studies. Additionally, most studies of the endometriotic microenvironment primarily focus on the epithelial component while the role of the stroma has been largely unexplored. Mesenchymal stem cells (MSC) are a critical component of the stromal microenvironment. Recently, we identified a key role of endometriosis derived MSCs (enMSCs) in altering ovarian clear cell carcinoma iron regulation. Interestingly, enMSCs resemble the primary endometrium derived MSCs, which suggested their role in endometrial cancer. This stromal subset is characterized by the loss of surface CD10 expression. It is known that cancer cells, particularly clear cell carcinoma (CCC), have a unique requirement for high levels of iron. We hypothesize that CD10 negative enMSCs promote growth of EAC and endometrial cancer through iron regulation. MSCs were isolated from primary human benign endometriosis, benign endometrium, or endometrial cancer. Flow cytometry was used to measure surface CD10 expression. We investigated the role of CD10 negative enMSCs on CCC iron regulation. Our results showed that CD10 negative enMSCs promote CCC growth by exporting iron through the upregulation of Hephaestin (HEPH) and Ferroportin (FPO) which then led to increase labile iron pool (LIP) in CCC cells. However, increasing the LIP does not occur with iron supplementation alone, this indicates the critical role of CD10 negative enMSCs in regulating iron handling in CCC cells. Additionally, our data showed that CD10 negative enMSCs alter the balance of Ferritin L and Ferritin H- the main iron storage proteins- in CCC cells. Mechanistically, our preliminary data showed that CD10 negative enMSCs directly donate Ferritin L into CCC cells. Further, CD10 negative enMSCs enhance Ferritin H degradation through the upregulation of ferritinophagy in CCC cells. In conclusion, our results indicate there is a sub-population of enMSCs, marked by the loss of CD10 expression, that enhances EAC and endometrial cancer cell growth through iron regulation. This highlights the existence of a tumor-promoting stromal cell within both the endometrium and endometriosis which can be capitalized on as an “Achilles' heel” to uncover novel treatment targets for EAC and endometrial cancer. Citation Format: Huda I. Atiya, Lan G. Coffman. Role of stromal CD10 expression in progression of endometrial and endometriosis-associated cancers [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr A014.

Simultaneous occurrence of two distinct histotypes of ovarian endometriosis-associated cancer in bilateral ovaries: implications for monoclonal histogenesis from a case report

BackgroundTransformation of endometriosis to malignancy is a rare occurrence. Clear cell ovarian cancer and endometrioid ovarian cancer are the two histotypes most consistently linked to endometriosis. The exact pathways leading to malignant transformation of endometriosis remain elusive.Case presentationA 41-year-old woman presented to our hospital with a ten days history of abdominal pain which was not responsive to medication. Pathological examination revealed an unexpected finding of bilateral endometriosis associated with distinct malignancies: a clear cell carcinoma in the right ovary and a well-differentiated endometrioid carcinoma in the left ovary. Molecular analysis indicated a shared somatic driver mutation in ING1 in the eutopic endometrium and the bilateral ovaries while simultaneously exhibiting specific genetic alterations unique to each carcinoma. Notably, several common mutation sites were also identified, including previously reported common oncogenes (KRAS, PIK3CA, ARID1A). This finding prompts the hypothesis of a possible monoclonal origin of the two tumours.ConclusionThis case represents an exceedingly rare occurrence of two different histotypes of ovarian endometriosis-associated cancer manifesting simultaneously in bilateral ovaries. Based on genetic analysis, we hypothesize that these malignancies may have a monoclonal origin, providing insights into understanding the different biological mechanisms underlying carcinogenesis.

Differences in the position of endometriosis-associated and non-associated ovarian cancer relative to the uterus

BackgroundPreoperative assessment of the histological type of ovarian cancer is essential to determine the appropriate treatment strategy. Tumor location may be helpful in this regard. The purpose of this study was to compare the position of endometriosis-associated (EAOCs) and non-associated (non-EAOCs) ovarian cancer relative to the uterus using MRI.MethodsThis retrospective study included patients with pathologically confirmed malignant epithelial ovarian tumors who underwent MRI at our hospital between January 2015 and January 2023. T2-weighted images of the sagittal and axial sections of the long axis of the uterine body were used for the analysis. Three blinded experienced radiologists independently interpreted the images and assessed whether the ovarian tumor was attached to the uterus, and the angle between the uterus and the tumor was measured. The presence of attachment and the measured angles were compared for each histology. In addition, the angles between EAOCs, including endometrioid carcinomas (ECs) and clear cell carcinomas (CCCs), were compared with non-EAOCs.ResultsIn total, 184 women (mean age, 56 years; age range, 20–91 years) were evaluated. High-grade serous carcinomas (HGSCs) were significantly smaller than the others and had significantly less uterine attachment than CCCs (p < 0.01 for all readers). According to the mean of the measured angles, CCCs were positioned significantly more posteriorly than HGSCs and mucinous carcinomas (p < 0.02), and EAOCs were positioned significantly more posteriorly to the uterus than non-EAOCs (p < 0.01).ConclusionHGSCs are often not attached to the uterus, and EAOCs are positioned more posteriorly to the uterus than non-EAOCs.Critical relevance statementHigh-grade serous carcinomas were often not attached to the uterus, and endometriosis-associated ovarian cancers were positioned more posteriorly to the uterus than non-endometriosis-associated ovarian cancers.Key points• The position of the ovarian tumor can be determined using MRI.• High-grade serous carcinomas had less attachment to the uterus.• Endometriosis-associated cancers were positioned more posteriorly to the uterus.• The location of ovarian tumors is helpful in estimating histology.Graphical abstract

Rare Epithelial Ovarian Cancers: Low Grade Serous and Mucinous Carcinomas.

The ovarian epithelial cancer histotypes can be divided into common and rare types. Common types include high-grade serous ovarian carcinomas and the endometriosis-associated cancers, endometrioid and clear-cell carcinomas. The less common histotypes are mucinous and low-grade serous, each comprising less than 10% of all epithelial carcinomas. Although histologically and epidemiologically distinct from each other, these histotypes share some genetic and natural history features that distinguish them from the more common types. In this review, we will consider the similarities and differences of these rare histological types, and the clinical challenges they pose.

Diagnostic Benefit of the Detection of Mitotic Figures in Endometriotic Lesions.

Objectives Endometriosis is a chronic disease which is diagnosed by surgical intervention combined with a histological work-up. Current international and national recommendations do not require the histological determination of the proliferation rate. The diagnostic and clinical importance of the mitotic rate in endometriotic lesions still remains to be elucidated. Methods In this retrospective study, the mitotic rates and clinical data of 542 patients with histologically diagnosed endometriosis were analyzed. The mean patient age was 33.5 ± 8.0 (17 – 72) years, and the mean reproductive lifespan was 21.2 ± 7.8 (4 – 41) years. Patients were divided into two groups and patientsʼ reproductive history and clinical endometriosis characteristics were compared between groups. The study group consisted of women with confirmed mitotic figures (n = 140, 25.83%) and the control group comprised women without proliferative activity according to their mitotic rates (n = 402, 74.27%). Results Women with endometriotic lesions and histologically confirmed mitotic figures were significantly more likely to have a higher endometriosis stage (p = 0.001), deep infiltrating endometriosis (p < 0.001), ovarian endometrioma (p = 0.012), and infertility (p = 0.049). A mitotic rate > 0 was seen significantly less often in cases with incidental findings of endometriosis (p = 0.031). The presence of symptoms and basic characteristics such as age, age at onset of menarche, reproductive lifespan and parity did not differ between the group with and the group without mitotic figures. Conclusion This study shows that a simple histological assessment of the mitotic rate offers additional diagnostic value for the detection of advanced stages of endometriosis. The possible role as a predictive marker for the recurrence of endometriosis or the development of endometriosis-associated cancer will require future study.

The effectiveness of antioxidant therapy (vitamin C) in an experimentally induced mouse model of ovarian endometriosis.

Objectives:This study investigates the therapeutic effect of vitamin C on the development of endometrial lesions and fecundity disorders in the ovarian induction model of mouse endometriosis.Methods:Ovarian endometriosis was surgically induced in 14 NMRI female mice (treatment group, N = 7) and (control group, N = 7). Three days after the second surgery (to assess endometriotic implant), the mice were randomized into two intervention groups: control (placebo) and treatment (50 mg/kg vitamin C every two days orally for four weeks) groups. In the oestrus phase, the mice were sacrificed. In macroscopic assessment, endometriotic implants were evaluated in size, volume, weight, growth score and adhesion score. The microscopic assessment examined the ovarian tissue (the number of antral follicles, corpus luteum and atretic follicles) and endometriotic lesion (histologic and trichrome fibrosis scores).Results:Post-treatment implant volume, growth score, adhesion extent score and adhesion severity score were significantly lower in the treatment group (vitamin C) in comparison with the control group (placebo) (p < 0.0001). The difference between the median weight of endometriotic implants, epithelialization of implant tissue, trichrome fibrosis scores and follicle number in the two groups (treatment and control) was statistically significant (p < 0.05). Atretic follicles were significantly decreased after vitamin C therapy (p < 0.05). Although the numbers of corpus luteum seemed to be more preserved in specimens from the control group, there was no statistical significance between the two groups’ histological scores.Conclusion:As a result, we may imply that vitamin C has a significant effect on reducing the induction and growth of endometrial implants, improving the fecundity function of ovaries, and consequently prevention of endometriosis-associated cancers. Further research is needed to improve targeted interventions resulting in the prevention and treatment of human endometriosis.

The multistep process of vaginal cancer arising from deep infiltrating endometriosis: a case report

BackgroundMalignant transformation of endometriosis in extraovarian sites remains rare. Furthermore, the process is not definitely understood.Case presentationHerein, we report the case of a 40-year-old premenopausal nulligravida woman who presented with vaginal bleeding and who was finally diagnosed with a vaginal cancer originating from endometriosis and with a synchronous endometrial cancer. A gynecologic examination revealed a multiple polypoid mass on the posterior vaginal fornix. Magnetic Resonance Imaging of the pelvis showed two masses abutting respectively on the anterior uterine wall, and in the rectovaginal septum. The patient underwent a total laparoscopic excision of the rectovaginal mass, radical hysterectomy and low anterior resection of the rectum. The lesions were diagnosed as endometriosis, endometriosis-associated complex hyperplasia and endometrioid cancer. Furthermore, a synchronous endometrioid endometrial cancer was reported.ConclusionsThis case revealed the multistep process of malignant transformation of deep infiltrating endometriosis. The progression was individualized between implantation sites and in the same organ.

Endometriosis-associated cancer: modern aspects of etiopathogenesis, treatment and rehabilitation

Aim: to analyze current literature sources on endometriosis-associated cancer (ЕАС) in gynecology.Materials and Methods. We searched for publications in the international scientific databases: eLibrary, Google Scholar, ScienceDirect, Cochrane Library, PubMed/MEDLINE and clinical research registries. For this systematic analysis, only full-text publications were used. We evaluated the reliability of evidence and the methodological quality of the studies. The data on the modern approach to the therapy and rehabilitation of women with external genital endometriosis (EGE) are presented. Search terms for publications in Russian and English were used: «endometriosis», «endometriosis-associated ovarian neoplasia», «oncology», «rehabilitation».Results. Despite the fact that EGE is considered a benign disease, there is a risk for its malignant transformation. However, the pathogenesis and pathomorphological mechanisms of ЕАС are not yet fully understood.Conclusion. Active management of the rehabilitation period for women with EGE provides an opportunity for early diagnosing recurrences that will provide early diagnostics ovarian ЕАС and improve the main indicators of the quality of life for such patients.

Malignant transformation of hepatic endometriosis: a case report and literature review

BackgroundExtrapelvic endometriosis is defined as the presence of ectopic endometrial tissue in structures outside the pelvis. Although extra-pelvic endometriosis is generally considered benign conditions, malignant potential within endometriotic foci occurs even after definitive surgery. Malignant transformation of hepatic endometriosis is extremely rare. Preoperative diagnosis of this cancer is difficult, and no guidelines on the optimal management currently exist. Here, we present a case report of malignant transformation of hepatic endometriosis and a brief literature review to highlight the current knowledge of the prevalence, clinical features, diagnosis, and management of this condition.Case presentationA 50-year-old woman with a 2-year duration of progressive right upper quadrant abdominal pain was admitted to the hospital. She underwent hysterectomy and bilateral salpingo-oophorectomy for benign conditions 4 years prior. Tumor markers demonstrated elevated carbohydrate antigen (CA)-199 112U/mL (normal range: 0–35U/mL) only. Radiological imaging suggested the presence of a 10.7 × 7.7-cm mass in the right lobe of the liver extending to the diaphragm. The intraoperative frozen sections suggested malignant tumor. Right hepatectomy with infiltrating diaphragm resection was performed. The final pathology with immunohistochemistry staining confirmed endometrioid adenocarcinoma in the liver originating from preexisting hepatic endometriosis. After the multidisciplinary team meeting, the consensus was surgery followed by adjuvant chemotherapy. To our knowledge, this is the first case of Chinese woman of a malignant liver tumor originating from endometriosis ever reported by reviewing the current English medical literature.ConclusionThough rare, extrapelvic endometriosis-associated cancers should be considered as differentiated diagnosis even after hysterectomy and bilateral salpingo-oophorectomy. This case highlights the importance of collaborative efforts across multiple disciplines for accurate diagnosis and appropriate treatment of malignant transformation of hepatic endometriosis.

Providing new insights into the endometriosisassociated cancer arising in episiotomy scars.

Endometriosis-associated malignancy in an episiotomy scar is rare. The predictive factors are poorly understood as are the mechanisms and pathways associated with implantation and malignant transformation. In this study we describe the cases reported in the literature of malignancies arising in endometriosis foci of an episiotomy scar. We identified 5 cases described between 1990 and 2016. These cases represent recurrence of endometriotic lesions in an episiotomy scar after previous diagnosis of endometriosis, 3 to 25 months before. Histology revealed clear cell tumours in 4 cases and a serous papillary carcinoma. The approach encompassed surgical removal for diagnosis and as part of the therapeutic strategy. Adjuvant treatment was performed depending on classical prognostic factors. Mechanisms of endometriosis implantation in scars include the influence of estrogens in the healing process and activation of COX-2, aromatase and matrix metalloproteinases. Nevertheless, for malignant transformation, other pathways seem to play a role, namely inflammation, immune response and oxidative stress, induced by iron deposits due to haemorrhage. Further studies are needed to allow the establishment of a predictive model for malignant transformation of endometriosis in episiotomy scars.

Whole-Exome Sequencing of Rare Site Endometriosis-Associated Cancer.

Malignant transformation of extraovarian endometriosis is rare, with the carcinogenesis mechanism unclear. To clarify the actionable variants of rare-site endometriosis-associated cancer (RSEAC), we performed whole-exome sequencing for the tumor, in two patients. The intestine was affected in both cases, although the histology was that of clear cell carcinoma and undifferentiated carcinoma, respectively. Therefore, the cases were referred to as endometriosis-associated intestinal tumors (EIATs). Actionable variants (all frameshift mutations) were identified in tumor suppressor genes ARID1A, PTEN, and p53; however, no oncogenic variants were identified. Both cases were microsatellite stable. The patient with undifferentiated carcinoma exhibited hypermutator and homologous recombination deficiency phenotypes. The dominant mutation signatures were signature 30 (small subset of breast cancers) and 19 (pilocytic astrocytoma) in patient 1, and signature 5 (small subset of breast cancers) and 3 (breast, ovarian, and pancreatic cancers) in patient 2. Immunohistochemistry revealed positive CD8 and PD-1 expression in both patients; patient 1 also showed positive PDL-1 expression. Our results suggest that RSEAC is associated with variants of tumor suppressor genes as epigenetic alterations. Mutation signature-based whole-exome sequencing could be useful to select an adjuvant chemotherapy regimen. High CD8 and PD-1 expression in RSEAC suggests that immune checkpoint inhibitors are useful for treatment.

Synthetic-lethal interactions between ATR inhibition and functional genetic and proteomic biomarkers to predict responses in endometriosis-associated cancers.

e18000 Background: Endometriosis is a common gynecologic disorder proven to be a precursor to several cancer types. We developed a potent and selective inhibitor (ATRN-119) of a critical DNA damage response (DDR) protein kinase: the ataxia telangiectasia and Rad3-related protein (ATR). Treatment with ATRN-119 is synthetically lethal with multiple cancer-associated changes in DDR pathways, representing a new and effective strategy to treat cancer. The objective of this study is to evaluate the overlap of DDR genes that respond to ATRN-119 and those mutated in endometriosis. Methods: We sequenced the exomes of 2,932 unrelated women with surgically-confirmed endometriosis (GERMLINE) and 274 tissue blocks containing endometriosis lesions (LESION). DNA was extracted using standard methods. Missense and truncation variants were analyzed. These data were compared to analysis of a whole proteome screen for factors that respond to exposure to ATRN-119 and may influence responsiveness to treatment. Factors observed in both methods were considered high-priority biomarker candidates and were experimentally tested for synthetic lethality with ATRN-119 treatment. Results: Analysis of endometriosis patients found 89% of the LESION samples had 2 or more DDR mutations vs 83% of the GERMLINE samples. There is an excess of DDR mutations per sample in LESION (5.5 mutations) vs GERMLINE (3.89 mutations) [p = 4.66x10-6, Mann Whitney test]. In parallel, we identified 92 genes as protein responders to ATRN-119 treatment. Mutations in 21 of these 92 genes show nominal association with surgical endometriosis (p &lt; 0.05). However, of these responsive genes, 18 are known TIER 1 cancer-driver genes and well-characterized mutations were found in three dominant genes in the LESION tissue (ATM, DDB1, and ARID1A). Overall 20% of the patients who’s LESION we examined subsequently developed an endometriosis-associated cancer. Both in vitro and in vivo studies confirmed synthetic-lethal interactions between ATRN-119 treatment and alteration of these genes. Conclusions: The overlap between DDR genes responding to ATRN-119 and those mutated in endometriosis-associated cancer suggest that genetic markers underlying response and resistance will be critical to extend the use of these drugs while increasing efficacy and minimizing toxicities. Furthermore, our data support the inclusion of endometriosis-associated cancer patients in planned ATRN-119 clinical trials.

Cancers associated with extraovarian endometriosis at less common/rare sites: A nationwide survey in Japan.

Endometriosis mostly affects the ovary but can also be present outside of the ovary including the pelvic peritoneum, intestine, urinary tract and lung. In case of ovarian endometriotic cyst, an increased risk of ovarian cancer, especially of clear cell and endometrioid histology, has been reported. However, because of the rarity, cancer occurrence from endometriosis at less common sites/rare sites is poorly understood. We conducted a nationwide survey on the less common/rare site endometriosis in 3539 authorized facilities in Japan. We requested to complete a case report form for each case, including information on the history of endometriosis, treatment for endometriosis, type of surgery, involved site(s) of cancer and endometriosis, histology of cancer, chemotherapy and outcome. Out of 1397 confirmed cases of less common/rare site endometriosis, 11 cases of rare site endometriosis-associated cancer (RSEAC) were reported: seven of them were associated with intestinal endometriosis, three were associated with urinary tract endometriosis and one was associated with umbilical endometriosis. Interestingly, the histology was endometrioid in seven (64%) cases, and serous, seromucinous borderline, clear cell and mucinous in one case each (10%), differing from the case of ovarian endometriosis-associated cancer, in which clear cell carcinoma are more common. Our nationwide survey on RSEAC has revealed that: (i) the incidence of malignant transformation may be lower than ovarian endometriosis, (ii) malignant transformation from endometriosis outside the abdominal cavity may be extremely rare and (iii) the histology of RSEAC is predominantly endometrioid type, suggesting an association of a hormonal effect.

How Benign is Endometriosis: Multi-Scale Interrogation of Documented Evidence

Endometriosis is an inflammatory disease characterized by the presence of endometrium-like tissue outside the uterus primarily on pelvic organs and tissues. It affects up to 15% of women in the reproductive age group and is often associated with pelvic pain and subfertility. Different theories explain how retrograde menstruation gives rise to endometrial deposits at ectopic sites, and how several other factors are involved in the progression of the disease. Its final diagnosis is established through direct visualization at laparoscopy or surgery followed by histological confirmation. Available epidemiological reports along with histopathological observations and molecular studies shed interesting light on the pathogenetic basis of different variants of the disease like deep infiltrating endometriosis and ovarian endometriosis. Evidence also suggests that endometriosis is a neoplastic condition which serves as a precursor of ovarian and endometrial cancers. In the present review, we have attempted to take a stock of the current epidemiological and molecular knowledge regarding endometriosis associated cancers and develop a model of functional network with interactions among critical genomic factors regulating cellular processes leading to fibrotic reaction. It is being conjectured that cyclic bleeding associated with inflammatory and oxidative stress followed by repeated tissue injury and repair along with recurrent estrogenic stimulation and ovulatory events in the pelvic environment bring about the complex phenotype of atypical endometriosis and associated neoplasm with a trade-off malignant transformation in high risk population. Finally, we have presented an algorithm for pre-emptive monitoring and management of endometriosis-associated cancers.

Genes' Interactions: A Major Contributor to the Malignant Transformation of Endometriosis.

The genetic and epigenetic factors that contribute to the malignant transformation of endometriosis are still under investigation. The objective of the present study was to investigate the genetic link between endometriosis and cancer by examining and correlating the latest clinical observations with biological experimental data. We collected updated evidence about the genetic relationship between endometriosis and cancers by conducting a comprehensive search of PubMed and Scopus databases, focusing on the papers published between January 2018 and January 2019. New insights into the mechanism of the malignant transformation of endometriosis have been published recently. The use of state-of-the-art techniques and methods, such as the genome-wide association study analysis and the weighted gene co-expression analysis, have significantly altered our understanding of the association between endometriosis and endometriosis-associated cancer development. Interestingly, the interactions formed between genes seem to play a pivotal role in the phenotypic expression of mutations. Therefore, the effect of single nucleotide polymorphisms and the function of the expression quantitative trait loci on genes’ expression have been the subject of many recent works. In addition, it has been discovered that genes, the mutations of which have been related to the development of endometriosis, play a role as hub genes. This may lead to new areas of research for understanding the mechanism of malignant transformation of the disease. Significant steps forward have been made towards the identification of factors that control the malignant transformation of endometriosis. Still, due to rarity of the event, a better-organized scheme for sampling on a global level should be adopted.

When Is "Type I" Ovarian Cancer Not "Type I"? Indications of an Out-Dated Dichotomy.

The dualistic classification of epithelial ovarian cancer (EOC) into “type I” and “type II” is widely applied in the research setting; it is used as a convenient way of conceptualizing different mechanisms of tumorigenesis. However, this classification conflicts with recent molecular insights of the etiology of EOC. Molecular and cell of origin studies indicate that while type II tumors could be classed together, type I tumors are not homogenous, even within the histological types, and can have poor clinical outcomes. Type II high grade serous carcinoma and type I low grade serous carcinomas best fit the description of the dualistic model, with different precursors, and distinct molecular profiles. However, endometriosis-associated cancers should be considered a separate group, without assuming an indolent course or type I genetic profiles. Furthermore, the very clear differences between mucinous ovarian carcinomas and other type I tumors, including an uncertain origin, and heterogeneous mutational spectrum and clinical behavior, indicate a non-type I classification for this entity. The impression that only type II carcinomas are aggressive, have poor prognosis, and carry TP53 mutations is an unhelpful misinterpretation of the dualistic classification. In this review, we revisit the history of EOC classification, and discuss the misunderstanding of the dualistic model by comparing the clinical and molecular heterogeneity of EOC types. We also emphasize that all EOC research, both basic and clinical, should consider the subtypes as different diseases beyond the type I/type II model, and base novel therapies on the molecular characteristics of each tumor.

Endometriosis-associated recto-sigmoid cancer: a case report

BackgroundEndometriosis is a relatively common condition in women of reproductive age. Malignant transformation of intestinal endometriosis is a very rare event. We report a case in which a patient with a history of endometriosis underwent surgery for malignant intestinal endometriosis.Case presentationA 55-year-old woman complained of rectorrhagia and intermittent abdominal pain. A neoplasm was revealed by colonoscopy, CT scan and F18-FDG PET/CT of the recto-sigmoidal colon. The patient underwent a rectal anterior resection, hysterectomy and bilateral salpingo-oophorectomy for treatment. According to the histological and immunohistochemical presentation, the diagnosis of endometriosis-associated recto-sigmoid cancer was confirmed. The patient was treated with adjuvant chemotherapy for 6 months. During the follow-up appointment 22 months later, there was clinical and radiographic evidence of recurrence in the rectum. The patient received chemotherapy again and will receive another surgery after two more cycles of chemotherapy.ConclusionWe report a case of malignant intestinal endometriosis. Although there is no standard therapy for malignant intestinal endometriosis due to the rarity of this disease, surgery and adjuvant chemotherapy seemed to be rational. This case indicates that local recurrence may be a common situation after standard therapy.

Abstract B39: The origins of endometriosis-associated cancers

Abstract Both clear cell ovarian carcinoma (CCOC) and endometrioid ovarian carcinoma (ENOC) are associated with ovarian endometriotic cysts, which is believed to be the precursor lesion of these cancers. Women with endometriotic cysts have up to a 3-fold increased risk of developing CCOC and ENOC. It is perplexing that these two clinically distinct histotypes of ovarian cancer arise from the same precursor lesion. We have performed whole-genome sequencing of ovarian cancer histotypes and found that while some genomic features are more common to one histotype than the other, there is not a single feature that is unique to either histotype. Lacking genomic evidence that could explain the differences between these histotypes, we hypothesized that these cancers arise from distinct cells of origin within endometrial tissue, and the cellular context accounts for their differences. We performed global proteomic analysis of ovarian cancer histotypes and identified CTH as a marker for CCOC. Upon examination of normal Müllerian tissues, we found that CTH is highly expressed in the ciliated cells of endometrium (both ectopic endometrium and endometriosis) and of the fallopian tube, with very little expression in the secretory cells of these tissues. We also find that other ciliated cell markers are expressed in CCOC, whereas endometrial secretory cell markers are expressed in ENOC. We propose a new model of CCOC and ENOC histogenesis wherein ENOC is derived from cells of secretory cell lineage whereas CCOC is derived from, or shares similarities to, cells of ciliated cell lineage. There remain, however, many unanswered questions. For example, while CCOC and ENOC occur at roughly equal prevalence, ciliated cells of the endometrium are rare compared to secretory cells. Cells in the endometriotic cyst are exposed to factors such as inflammation and reactive oxygen species, which could influence differentiation of endometrial progenitor cells into the secretory or ciliated cell lineage. To test factors that promote ciliated cell differentiation in normal endometrium, we treated organoid cultures of normal endometrium with IL-6 and Notch pathway modulators. We propose that ovarian cancer histotypes arise from different cells of origin and that the biology of the normal cells will be partly responsible for determining the phenotype of the cancers. Citation Format: Dawn Cochrane, Basile Tessier-Cloutier, Katherine Lawrence, Tayyebeh Nazeran, Anthony Karnezis, Clara Salamanca, Timothy Lee, Angela Cheng, Jessica McAlpine, Lien Hoang, Blake Gilks, David Huntsman. The origins of endometriosis-associated cancers. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B39.