Novel insights on the malignant transformation of endometriosis into ovarian carcinoma

Factors in malignant transformation of ovarian endometriosis: A narrative review

Endometriosis is a common estrogen-dependent inflammatory disease with a chronic course and a tendency to recur. The association between endometriosis and cancer has been studied for several years. Numerous reports have demonstrated a strong association between specific ovarian malignancies and endometriotic lesions. Atypical endometriosis has been widely described as a malignant precursor to ovarian epithelial tumors, particularly clear cell carcinomas and endometrioid carcinomas. These histological types associated with endometriosis develop predominantly in the ovary rather than in extragonadal sites. The detailed molecular mechanism of etiology remains unclear. Recent studies have analyzed the genetic and molecular mechanisms involved in endometriosis-associated ovarian cancer. A critical role appears to be played by a carcinogenic model based on iron-induced oxidative stress, which is typical of the endometriosis microenvironment. It has been hypothesized that trans-tubal reflux of blood, endometrial cells and associated iron-induced oxidative stress underlie the development of endometriosis-associated ovarian cancer. However, the multifactorial mechanisms of this malignant transformation are not fully understood. The aim of this review is to summaries the current epidemiological, histopathological, genetic and molecular findings in the progression of endometriosis-associated ovarian cancer.

The malignant transformation of endometriosis: Is there a left lateral predisposition of ovarian clear cell and endometrioid carcinomas?

INTRODUCTION

Endometriosis affects 10% of women of reproductive age. There is evidence for a left lateral predisposition of endometriotic lesions and a 1.9-fold greater risk of ovarian cancer in endometriosis. The aim of this study is to determine whether a left lateral predisposition of ovarian clear-cell carcinoma (CCC) and endometrioid carcinoma (EC) exists.

MATERIALS AND METHODS

A retrospective cohort study of all EC and CCC patients in Northern Ireland between March-2011 and June-2018. ANOVA was used to analyse preoperative prediction of stage, chi-squared (χ2) was used to compare left- and right-sided masses. Survival was estimated using Kaplan-Meier and log-rank test. A p-value <0.05 was considered significant.

RESULTS

158 patients were identified (95 EC, 55 CCC, 8 mixed). Mean age was 57.65 years with 69% presenting at stage 1. The mean CA125 was 559 U/mL (p = 0.850) and mean abdominal mass size was 14.12 cm (p = 0.732). The most common presenting symptom was an abdominal mass (37%). Despite 67% of patients having endometriosis on final pathology, only 8.9% had a known history pre-operatively. 51% of tumours were located on the left (p = 0.036). For unilateral tumours this was significant for EC (P = 0.002) but not for CCC (P = 0.555). The 1-, 3- and 5-year overall survival for all types/stages was 85%, 78% and 71% respectively.

CONCLUSION

While CCC and EC are associated with endometriosis, only EC exhibits a left lateral predisposition. There is no association between preoperative CA125 or abdominal mass size and stage of disease.

Hormone Replacement Therapy and Risks of Various Cancers in Postmenopausal Women with De Novo or a History of Endometriosis

This study examined the impact of hormone replacement therapy (HRT) on the occurrence of various cancers in postmenopausal women with de novo or a history of endometriosis. In the datasets for ten cancers (cervical, uterine, ovarian, breast, colon, gastric, liver, lung, pancreatic, and thyroid), women who received HRT (the HRT group) and those who did not (the control group) were selected by a 1:1 matching with those who met the study criteria. In the dataset for each cancer, the incidence of each cancer was very low (0.2% to 1.5% in the HRT group and 0.2% to 1.3% in the control group). The duration of HRT was 1.3 ± 2.1 years. After adjusting for co-variables, HRT was a significant risk factor for uterine cancer (p < 0.05). However, the risk of liver cancer decreased significantly with duration of HRT (p < 0.05). Moreover, combined estrogen and progesterone decreased the risks of liver and thyroid cancers significantly (p < 0.05), and estrogen alone decreased the risks of breast and lung cancers significantly (p < 0.05). Tibolone was not associated with the risk of any of the cancers assessed. These results can help guide the use of HRT in women with de novo or a history of endometriosis.

Correlation of clinicopathological and prognostic characteristics between endometriosis-associated and primary ovarian cancer

BACKGROUND

The main aim of this study was to establish the clinicopathological and prognostic correlations between endometriosis-associated and non-endometriosis-associated primary ovarian cancer, with a view to providing a reference guide for revision of diagnostic criteria for malignant transformation of endometriosis.

METHODS

Clinicopathological and follow-up data of 174 patients with clear cell and endometrial ovarian cancer were retrospectively extracted. Cases were divided into endometriosis-associated and non-endometriosis-associated primary ovarian cancer for comparative analysis of clinicopathological characteristics and prognosis.

RESULTS

Average age and post-menopausal rate in the endometriosis-associated ovarian cancer group were lower relative to the primary ovarian cancer group (P < 0.05). Body mass index, age at menopause, operation history, dysmenorrhea, complications, tumor size, tumor side, ascites, CA125, HE4, CA19.9, stage, differentiation, expression of ER, PR, P53, P16, Ki67, MMR, HNF-1β and Napsin A were not significantly different between the groups (P > 0.05). Furthermore, rates of resistance to platinum chemotherapy, relapse, progression-free survival and overall survival were comparable between the two groups (P > 0.05).

CONCLUSION

Endometriosis-associated and primary ovarian cancers of the same pathological type are speculated to be homologous in terms of origin from malignant transformation of endometriosis. It may therefore be necessary to revise the diagnostic criteria for ovarian endometriosis malignancy.

Impact of Hormone Replacement Therapy on Risk of Ovarian Cancer in Postmenopausal Women with De Novo Endometriosis or a History of Endometriosis

The effect of hormone replacement therapy (HRT) on the malignant transformation of postmenopausal endometriosis remains unclear. This study aimed to investigate the impact of HRT on ovarian cancer occurrence in postmenopausal women with de novo endometriosis or a history of endometriosis. A total of 10,304 women that received HRT (the HRT group) and 10,304 that did not (the control group) were selected by 1:1 matching those that met the study criteria. Incidences of ovarian cancer (0.3% in the HRT group and 0.5% in the control group) and cumulative incidence rates of ovarian cancer were similar in the two groups. The overall mean duration of HRT was 1.4 ± 2.2 years, but the duration of HRT in women with ovarian cancer was 2.2 ± 2.9 years. After adjusting for co-variables, receipt of HRT, duration of HRT, combined use of estrogen and progesterone, and tibolone were not found to be risk factors for ovarian cancer. However, the use of estrogen alone was found to be a significant risk factor for ovarian cancer (HR 2.898; 95% CI 1.251–6.715; p = 0.013). With the exception of HRT using estrogen alone, HRT did not increase the risk of ovarian cancer in postmenopausal women with a history of endometriosis or de novo endometriosis.

Next-generation sequencing shows the genomic features of ovarian clear cell cancer and compares the genetic architectures of high-grade serous ovarian cancer and clear cell carcinoma in ovarian and endometrial tissues

Ovarian clear cell carcinoma (OCCC) is a special histological type of epithelial ovarian cancer (EOC) that is not derived from epithelial cells of the ovarian or fallopian tube as the most common type of ovarian cancer, high-grade serous ovarian carcinoma (HGSOC), but is closely related to endometriosis and similar to endometrial clear cell carcinoma (ECCC) at morphologic and phenotypic features. However, limited data was shown in OCCC genomic features and compared with that in OCCC, HGSOC and ECCC. Herein, we utilized next-generation sequencing analysis of a panel of 1,021 genes to profile the mutational alterations in 34 OCCC and compared them to those from HGSOC (402 cases) and ECCC (30 cases). In result, the ARID1A and PIK3CA are high-frequency mutations of OCCC. Clonal architectures showed that all the mutations of genes occur in the later stage in the OCCC progress, whereas KRAS mutation is the earlier event compared with mutation of ARID1A or PIK3CA, which usually occurs in a group of ARID1A or PIK3CA mutations. The mutation frequency of main driver genes is similar between OCCC and ECCC, while TP53 is the main mutation in HGSOC and ECCC. Shared mutational signatures between OCCC and ECCC tissues with commonly observed a C>T change indicated a common carcinogens-exposed between these two carcinomas, but HGSOC and ECCC have common and distinct mutational signatures across cohorts respectively. In addition, we identified some novel CNV gains in NF1, ASXL1, TCF7L2, CREBBP and LRP1B and loss in ATM, FANCM, RB1 and FLT in OCCC. Our study offered a new perspective for OCCC tumorigenesis from two organs, the ovary and uterus, at genomic architectures and revealed novel CNV events for helping to provide theoretical support for OCCC treatment.

Review the progression of ovarian clear cell carcinoma from the perspective of genomics and epigenomics

Ovarian clear cell carcinoma (OCCC) is a rare subtype of epithelial ovarian cancer with unique molecular characteristics, specific biological and clinical behavior, poor prognosis and high resistance to chemotherapy. Pushed by the development of genome-wide technologies, our knowledge about the molecular features of OCCC has been considerably advanced. Numerous studies are emerging as groundbreaking, and many of them are promising treatment strategies. In this article, we reviewed studies about the genomics and epigenetics of OCCC, including gene mutation, copy number variations, DNA methylation and histone modifications.

Peritoneal Pathology Review: Mullerian, Mucinous and Mesothelial Lesions

This review provides an overview of the pathology of selected benign and malignant lesions of the female peritoneum and their often-encountered differential diagnoses. It includes endometriosis and its related lesions, endosalpingiosis, pseudomyxoma peritonei (PMP) and related ovarian/appendiceal pathology, and malignant and benign mesothelial tumors. The current terminology associated with PMP is also discussed.

Friend or foe? The prognostic role of endometriosis in women with clear cell ovarian carcinoma. A UK population-based cohort study

PURPOSE

The prognostic role of endometriosis amongst women with ovarian clear cell carcinoma (OCCC) remains debatable. The aim of this study was to ascertain the effect of endometriosis on the prognosis of OCCC.

METHODS

A retrospective review of the medical records of 94 women diagnosed and treated for OCCC at a tertiary gynaecological cancer centre in the UK, spanning the period 2010-2019. Women were divided into two groups according to the presence of endometriosis. Clinico-pathological characteristics, progression-free survival (PFS) and overall survival (OS) were collated between the two groups.

RESULTS

Forty-six cases of endometriosis-free OCCC (Ef-OCCC) were collated with 48 cases of endometriosis-related OCCC (Er-OCCC). There was no significant difference between the two groups regarding age (p-value = 0.2), FIGO stage (p-value = 0.8), residual disease (RD) (p-value = 0.07), adjuvant chemotherapy agent (p-value = 0.4) or chemo-resistance (p-value = 0.9). The presence of endometriosis did not significantly affect either OS or PFS. The median OS in the Ef-OCCC and Er-OCCC was 55.00 (95% CI 32.00-189.00) and 71.00 (95% CI 47.00-97.00; log rank = 1.35, p-value = 0.2) months. The median PFS in the Ef-OCCC and Er-OCCC group was 39.00 (95% CI 19.00-143.00) and 39.00 (95% CI 19.00-62.00; log rank = 0.7, p-value = 0.4) months. Survival differences between the two groups were not significant after stratification analysis for independent prognosticators.

CONCLUSION

Endometriosis was not independently associated with the prognosis of OCCC either in crude analysis or after stratification for stage and RD. Further larger, well-designed prospective studies are warranted to draw firmer conclusions on the intrinsic link between endometriosis and OCCC.

[Endometriosis and adenomyosis]

Diffuse adenomyosis, focal adenomyosis, ovarian endometrioma, superficial endometriosis and deep infiltrating adenomyosis are all defined by the presence of an endometrioid tissue in an ectopic location that is at distance from the endometrium. Although frequently associated, these lesions represent different clinico-pathological entities that the pathologist should recognized. Herein, we review the clinical and pathological features of these entities, as well as related current physiopathological understandings and differential diagnoses that could be raised by some morphological variants. The statistical association between endometriosis and several ovarian tumors, mainly endometrioid and clear cell carcinomas and seromucinous borderline tumors is well established and we present some molecular and morphological features that support this transformation potential.

Malignant Transformation and Associated Biomarkers of Ovarian Endometriosis: A Narrative Review

This review focuses on pathogenesis of endometriosis, its possible biomarkers and role in endometriosis-associated ovarian cancer. We analyzed various databases to obtain new insights, theories, and biomarkers associated with endometriosis. There are several theories of endometriosis development and biomarker changes including atypical forms. A number of studies have attempted to establish specific, reliable biomarkers to help diagnose endometriosis and endometriosis-associated diseases on the basis of different pathogenetic pathways. Nevertheless, despite intensive research extending even to the molecular level, the origin, natural history, malignant transformation, and laboratory management of endometriosis and related diseases are not yet clearly defined. Therefore, early laboratory diagnoses of endometriosis, its atypical form, and endometriosis-associated ovarian tumors are important problems that require further study in the context of advanced therapeutic strategies to provide maximal health benefits to patients.

Identification of novel mutations of ovarian cancer-related genes from RNA-sequencing data for Japanese epithelial ovarian cancer patients

Ovarian cancer has the highest mortality rate among gynecological cancers. Gene mutations are involved in the carcinogenesis, metastasis, and therapeutic response in ovarian cancer. However, the variety and proportion of gene mutation is not fully analyzed in Japanese ovarian cancer patients, especially, in those with recurrent tumors. In the present study, RNA-sequencing was performed for 32 clinical ovarian specimens obtained from 24 Japanese patients (24 primary cancer specimens and 8 recurrent specimens paired with corresponding primary cancer specimens). Mutations in 24 primary specimens were analyzed by comparing the sequence data mapped on RefSeq genes with those in the public online databases BRCA Exchange, COSMIC, ClinVar, and cBioportal. Mutations were observed in TP53 in 16 specimens (67%), BRCA1 in 9 (38%), BRCA2 in 13 (54%), ARID1A in 3 (13%), PIK3CA in 2 (8%), KRAS in 1 (4%), PTEN in 1 (4%), and CTNNB1 in 1 (4%), excluding synonymous mutations. Among those identified muations, 13 of 14 mutations in TP53, 10 of 11 mutations of BRCA1, 10 of 23 mutation positions of BRCA2, none of 7 mutations of ARID1A, 1 mutation of PIK3CA, and 1 mutation of CTNNB1 were consistent with those reported in the public online databases; however, the other mutations identified were novel. Comparison between matched-paired specimens of primary and recurrent tumors revealed the changes of mutational status in expressed RNAs. RNA-sequencing-based mutation analysis will be useful to reveal ethnic differences of gene mutations in ovarian cancer and to understand the contribution of gene mutations to recurrence.

How can we manage patients over forty with endometriosis?

Peri/postmenopausal endometriosis is not as rare as once we thought. Accumulated data revealed that around 1/3-1/4 of women with surgically-diagnosed endometriosis after the age of 40. The uneasiness of the issue of malignant transformation or malignancy in such women created a challenge for us. Here the management strategy for women with endometriosis after the age of 40 is discussed in the light of scientific evidence.

Pathology of Endometrioid and Clear Cell Carcinoma of the Ovary

This review is an appraisal of the current state of knowledge of 2 enigmatic histotypes of ovarian carcinoma: endometrioid and clear cell carcinoma. Both show an association endometriosis and the hereditary nonpolyposis colorectal cancer (Lynch) syndrome, and both typically present at an early stage. Pathologic and immunohistochemical features that distinguish these tumors from high-grade serous carcinomas, each other, and other potential mimics are discussed, as are staging, grading, and molecular pathogenesis.

Ovarian Cancer Incidence in the Multi-Ethnic Asian City-State of Singapore 1968-2012

Purpose:

We investigate ovarian cancer incidence between 1968 and 2012 in Singapore, a multiethnic Asian city state.

Methods:

Aggregated data of ovarian epithelial cancer numbers and estimated person-years from 1968 to 2012 were obtained from Singapore Cancer Registry. Age-Period-Cohort modelling was performed.

Results:

The age-standardised incidence rate of ovarian cancer increased from 5.8 to 12.5 per 100,000 per year between 1968 and 2012, while the age-standardised mortality rate has remained stable. This increase was higher among Malays (5.1 to 14.0 per 100,000 per year), compared to Chinese and Indians. Serous carcinoma showed the greatest increase in incidence from 0.4 to 3.4 per 100,000 per year. Period effects were seen in the ovarian cancer incidence trend in Chinese women, but not Malay and Indian women. Clear cell and mucinous carcinoma subtypes were more common in Chinese than in Malay and Indian women. Stage at diagnosis for the years 2003-2010 differed by subtype, and the majority of patients with serous carcinomas presented at a later stage compared to those with clear cell or mucinous carcinomas.

Conclusion:

Ovarian cancer incidence rates have doubled in 40 years in Singapore. There were ethnic differences in incidence rates and ovarian cancer subtypes.

Clinical Characteristics of Clear Cell Ovarian Cancer: A Retrospective Multicenter Experience of 308 Patients in South Korea

Purpose

The purpose of this study was to evaluate clinical characteristics and treatment pattern of ovarian clear cell carcinoma (OCCC) in Korea and the role of adjuvant chemotherapy in early-stage.

Materials and Methods

Medical records of 308 cases of from 21 institutions were reviewed and data including age, performance status, endometriosis, thromboembolism, stage, cancer antigen 125, treatment, recurrence, and death were collected.

Results

Regarding stage of OCCC, it was stage I in 194 (63.6%), stage II in 34 (11.1%), stage III in 66 (21.6%), and stage IV in 11 (3.6%) patients. All patients underwent surgery. Optimal surgery (residual disease ≤ 1 cm) was achieved in 89.3%. Majority of patients (80.5%) received postoperative chemotherapy. The most common regimen was taxane-platinum combination (96%). Median relapse-free survival (RFS) was 138.5 months for stage I, 33.4 for stage II, 19.3 for stage III, and 9.7 for stage IV. Median overall survival (OS) were not reached, 112.4, 48.7, and 18.3 months for stage I, II, III, and IV, respectively. Early-stage (stage I), endometriosis, and optimal debulking were identified as favorable prognostic factors for RFS. Early-stage and optimal debulking were also favorable prognostic factors for OS. Majority of patients with early-stage received adjuvant chemotherapy. However, additional survival benefit was not found in terms of recurrence.

Conclusion

Majority of patients had early-stage and received postoperative chemotherapy regardless of stage. Early-stage and optimal debulking were identified as favorable prognostic factors. In stage IA or IB, adding adjuvant chemotherapy did not show difference in survival. Further study focusing on OCCC is required.

Long-term oncologic outcome and its prognostic indicators in reproductive-age women with ovarian clear-cell carcinoma

BACKGROUND

Clear-cell carcinoma (CCC) in reproductive-age women is likely to become an increasingly critical issue regarding possibilities of infertility, hormonal dysfunction, and mortality. The aim of this study was to examine the long-term oncologic outcome and its prognostic indicators based on a multicentric cohort of young patients with CCC.

PATIENTS AND METHODS

During the period of 1990-2015, a total of 164 patients aged 45-year-old or younger were enrolled in the study. Clinicopathologic data of these young patients with CCC collected under a centralized pathological review system were subjected to uni- and multivariable analyses to evaluate overall survival (OS).

RESULTS

The median follow-up was 73.8 months (range 5.2-244.2) in the surviving patients. Among these patients, 104 (63.4%) had FIGO I disease, and 22 (13.4%), 31 (18.9%), and 7 (4.3%) had II, III, and IV disease, respectively. The 5-year OS rate was 74.5%. On stratification by the FIGO stage, the 5-year OS rates were as follows: stage I (90.2%), stage II (57.9%), and stage III/IV (39.3%), respectively (P < 0.0001). Confining analysis to stage I patients, there was no difference in OS between those who underwent fertility-sparing surgery and those who received radical surgery (P = 0.1593). In relapsed patients, the median survival after recurrence was 11.6 months. In multivariable analysis of stage I patients, the capsule status was an independent prognostic indicator of OS {IC2/IC3 vs. IA/IC1: HR 4.293 (95% CI 1.140-16.422), P = 0.0318}.

CONCLUSION

CCC patients staged greater than IC2/IC3 show a markedly increased risk of mortality. Thus, it is important to diagnose patients staged under IC2/IC3.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Endometriosis-associated ovarian cancer: What have we learned so far?

Endometriosis is defined as the presence of ectopic endometrial tissue outside of the uterine cavity, most commonly in the ovaries and peritoneum. It is a complex disease that is influenced by multiple factors. It is also a common gynecological disorder and affects approximately 10-15% of all women of reproductive age. Recent molecular and pathological studies indicate that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), particularly endometrioid and clear cell ovarian cancers. Although histological and epidemiological studies have demonstrated that endometriosis has a malignant potential, the molecular mechanism that underlies the malignant transformation of endometriosis is still controversial, and the precise mechanism of carcinogenesis must be fully elucidated. Currently, the development and improvement of a new sequencing technology, next-generation sequencing (NGS), has been increasingly relevant in cancer genomics research. Recently, NGS has also been utilized in clinical oncology to advance the personalized treatment of cancer. In addition, the sensitivity, speed, and cost make NGS a highly attractive platform compared to other sequencing modalities. For this reason, NGS may lead to the identification of driver mutations and underlying pathways associated with EAOC. Here, we present an overview of the molecular pathways that have led to the current opinions on the relationship between endometriosis and ovarian cancer.

Identification of potential key genes associated with ovarian clear cell carcinoma

Background

Ovarian cancer is the major cause of death from cancer among females worldwide. Ovarian clear cell carcinoma (OCCC) is considered a distinct histopathologic subtype with worse prognosis and resistance to conventional chemotherapy.

Materials and methods

We analyzed five microarray datasets derived from the Gene Expression Omnibus database. GEO2R tool was used to screen out differentially expressed genes (DEGs) between OCCC tumor and normal ovary tissue. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed using the g:Profiler database and Cytoscape. Based on Search Tool for the Retrieval of Interacting Genes, we performed protein-protein interaction (PPI) network analysis on the DEGs. Real-time PCR (RT-PCR) and Western blotting in frozen samples of normal ovary and OCCC were performed to verify the expression difference of hub genes in OCCC patients.

Results

Thirty upregulated DEGs and 13 downregulated DEGs were identified by cross referencing. Six were chosen as hub genes with high connectivity degree via PPI network analysis, including two upregulated and four downregulated. RT-PCR and Western blotting results showed significant expression difference of the two upregulated genes, SPP1 and EPCAM, between tumor and normal tissues.

Conclusion

Our research suggests that SPP1 and EPCAM are overexpressed in OCCC compared with normal ovary tissue. Clinical study of large sample is required to evaluate the value of SPP1 and EPCAM in the precision treatment and prognostic influence on OCCC in the future.

Long-term survival of a patient with malignant transformation of extragonadal endometriosis treated solely with chemotherapy: A case report

A 52-year-old woman presented to our hospital complaining of genital bleeding and was found to have a 50-mm vaginal tumor that involved the bladder, rectum, and small bowel and extended to the left pelvic side wall. Her history included a bilateral salpingo-oophorectomy and a total abdominal hysterectomy for fibroids and endometriosis. She had been prescribed estrogen replacement therapy (1.25 mg/day) following the second surgery and continued it for 8 years. The pathology of the vaginal biopsy showed endometrioid adenocarcinoma. Total pelvic exenteration was recommended for complete resection, but she chose chemotherapy (paclitaxel 175 mg/m² and carboplatin AUC:6). Clinical complete remission was obtained for 11 years. She had a recurrence 11 years later. She was again found to have a 5-cm vaginal tumor. Surgical excision with upper vaginectomy was performed. The tumor was resected without invasion of the bladder, rectum and small bowel. Histologic examination of the specimen confirmed clear cell carcinoma with endometriosis. Chemotherapy may be the first-line treatment that can preclude aggressive surgery for malignant transformation of extragonadal endometriosis. However, combined chemotherapy and surgery is necessary for this disease.

Ovarian Clear Cell Carcinoma: From Morphology to Molecular Biology

Ovarian clear cell carcinoma (oCCC) is a distinctive subtype of ovarian carcinoma, with peculiar genetic and environmental risk factors, precursor lesions, molecular events during oncogenesis, patterns of spread, and response to treatment. Because of low response to chemotherapy and poor prognosis in advanced stages, there is growing interest in investigating the molecular pathways involved in oCCC development, in order to individualize novel/molecular targeted therapies. Until now, the main molecular genetic changes associated with oCCC remain to be identified, and, although several molecular changes have been reported in clear cell tumors, most studies have analyzed a limited number of cases; therefore, the true prevalence of those changes is not known. The present review will present the clinicopathologic features of oCCC, from morphology to molecular biology, discussing the diagnostic and treatment challenges of this intriguing ovarian carcinoma.

Improved clinical outcomes of patients with ovarian carcinoma arising in endometriosis

BACKGROUND

Despite enormous efforts to dissect the role of endometriosis in ovarian cancer development, the difference in prognosis between ovarian cancer patients with or without endometriosis remains elusive. The purpose of this study is to assess the association between endometriosis and the prognosis in patients with ovarian cancer.

RESULTS

Ovarian cancer arising in endometriosis tended to be presented as clear cell histology, early stage, less intraperitoneal metastasis and ascites, and lower CA125 level compared with those without endometriosis. Multivariate Cox regression analysis identified endometriosis as an independent prognostic factor for progression free survival (P = 0.002) and overall survival (P = 0.009) in all patients and especially for early stage. A nomogram integrating endometriosis, FIGO stage and CA125 was established to predict progression free survival and overall survival.

MATERIALS AND METHODS

This study retrospectively enrolled 196 ovarian cancers arising or not in endometriosis judged by adjunctive use of CD10 immunohistochemistry in conjunction with H&E staining specimens. Clinicopathologic variables, progression-free survival (PFS) and overall survival (OS) were recorded. Kaplan-Meier analysis was performed to compare survival curves. Cox regression models were used to analyze the effect of endometriosis on PFS and OS. A prognostic nomogram was constructed based on the independent prognostic factors identified by multivariate analysis.

CONCLUSIONS

Endometriosis is an independent predictor of prognosis in ovarian cancer patients.

Affinity-purified DNA-based mutation profiles of endometriosis-related ovarian neoplasms in Japanese patients

Aim

Endometriosis-related ovarian neoplasms (ERONs) have recently attracted considerable attention; however, the prevalence and patterns of ARID1A and POLE mutations in ERONs have not been studied in detail. The aim of this study was to investigate not only the carcinogenesis of ERONs, but also the prognostic significance of several gene mutations in this cohort. We used DNA purified from only tumor epithelial cells, from which fibroblasts were removed, using a specific method we called "liquid microdissection".

Methods

Tissue samples from 22 ovarian carcinomas (13 endometrioid, and nine clear cell) were used. Tumor cells were isolated using a cell sorting system and DNA was purified from tumor epithelial cells. Nucleotide sequencing was conducted to analyze the mutational status of ARID1A, p53, PTEN, POLE, PIK3CA, and KRAS.

Results

In ERONs, the frequencies of somatic mutations in ARID1A, p53, POLE, PTEN, PIK3CA, and KRAS were 19/20 (95.0%), 7/19 (36.8%), 9/22 (40.9%), 13/19 (68.4%), 3/19 (15.8%), and 1/9 (11.1%). The frequency of ARID1A mutations was significantly higher than that reported previously. Kaplan-Meier survival analysis revealed that mutations in all genes, including POLE, were not associated with patient prognosis in our Japanese cohort.

Conclusions

Our results suggest that the frequency of ARID1A mutations in ERONs may be higher than that previously reported. In addition, the "liquid microdissection" method that we chose for DNA purification could be used to obtain high-quality sequencing results. The findings suggest that ARID1A mutations represent the basis of ERON carcinogenesis; other subsequent gene mutations may result in the progression of carcinogenesis.

Endometriosis-associated ovarian neoplasia

This article reviews the most relevant pathological and molecular features of ovarian tumours that are associated with endometriosis. Endometriosis is a common condition, affecting 5-15% of all women, and it has been estimated that 0.5-1% of cases are complicated by neoplasia. The most common malignant tumours in this setting are endometrioid adenocarcinoma and clear cell adenocarcinoma, each accounting for approximately 10% of ovarian carcinomas in Western countries. A minority of cases are associated with Lynch syndrome. These carcinomas are often confined to the ovaries at presentation in which case they have relatively favourable outcomes. However, high-stage tumours, particularly clear cell carcinomas, generally have a poor prognosis and this partly reflects relative resistance to current treatment. Histological diagnosis is straightforward in the majority of cases but some variants, for example endometrioid carcinomas with sex cord-like appearances or oxyphil cells, may create diagnostic difficulty. Similarly, clear cell carcinomas can show a range of architectural and cytological patterns that overlap with other tumours, both primary and metastatic, involving the ovaries. Endometriosis-associated borderline tumours are less common, and they often show mixed patterns of differentiation (seromucinous tumours). Atypical endometriosis may represent an intermediate step in neoplastic progression and some of these lesions demonstrate immunohistological and molecular alterations similar to those observed in endometriosis-related tumours. ARID1A mutations are relatively common in all of these tumours, but each has additional characteristic molecular alterations which are likely to be of increasing clinical relevance as targeted therapies are developed. Less is known of the pathogenesis of rarer endometriosis-associated ovarian tumours including endometrioid stromal sarcoma, mesodermal (Müllerian) adenosarcoma, and carcinosarcoma. This article also briefly reviews the issue of synchronous endometrioid carcinomas of the endometrium and the ovary, including the most recent developments on pathogenesis.

Clinical outcomes of patients with clear cell and endometrioid ovarian cancer arising from endometriosis

OBJECTIVE

The aim of this investigation is to compare outcomes of patients according to the presence of cancer arising from endometriosis in ovarian clear cell carcinoma (CCC) and endometrioid carcinoma (EC).

METHODS

This study retrospectively investigated 224 CCC and EC patients treated in Samsung Medical Center from 2001 to 2015 to identify cancer arising from endometriosis according to Sampson and Scott criteria. Propensity score matching was performed to compare patients arising from endometriosis to patients without endometriosis (ratio 1:1) according to stage, age, lymph node metastasis (LNM), cancer antigen (CA)-125 level, and residual status after debulking surgery.

RESULTS

Forty-five cases arising from endometriosis were compared with 179 cases without endometriosis. CCC and EC arising from endometriosis tended to present with early age (mean, 45.2 vs. 49.2 years; p=0.003), early-stage (stages I and II, 92.7% vs. 62.3%; p<0.001), lower CA-125 level (mean, 307.1 vs. 556.7; p=0.041), higher percentages of no gross residual disease after surgery (87.8% vs.56.8%; p=0.001), and higher percentages of negative LNM (82.9% vs. 59.0%; p=0.008) compared to cases without endometriosis. Kaplan-Meier curves for progression-free survival (PFS) and overall survival (OS) showed better outcomes for groups with cancer arising from endometriosis (p=0.014 for PFS; and p=0.010 for OS). However, the association with endometriosis was not significant in multivariate analysis. Also, after propensity score matching, survival differences between the 2 groups were not significant.

CONCLUSION

CCC and EC arising from endometriosis are diagnosed at an earlier age and stage. However, cancer arising from endometriosis was not a significant prognostic factor.

The management of menopause in women with a history of endometriosis: a systematic review

BACKGROUND

Endometriosis is typically regarded as a premenopausal disease, resolving after natural or iatrogenic menopause due to declining oestrogen levels. Nonetheless, case reports over the years have highlighted the incidence of recurrent postmenopausal endometriosis. It is now clear that both recurrence and malignant transformation of endometriotic foci can occur in the postmenopausal period. Postmenopausal women are commonly treated with hormone replacement therapy (HRT) to treat climacteric symptoms and prevent bone loss; however, HRT may reactivate endometriosis and stimulate malignant transformation in women with a history of endometriosis. Given the uncertain risks of initiating HRT, it is difficult to determine the best menopausal management for this group of women.

OBJECTIVE AND RATIONAL

The aim of this study was to systematically review the existing literature on management of menopausal symptoms in women with a history of endometriosis. We also aimed to evaluate the published literature on the risks associated with HRT in these women, and details regarding optimal formulations and timing (i.e. initiation and duration) of HRT.

SEARCH METHODS

Four electronic databases (MEDLINE via OVID, Embase via OVID, PsycINFO via OVID and CINAHL via EbscoHost) were searched from database inception until June 2016, using a combination of relevant controlled vocabulary terms and free-text terms related to 'menopause' and 'endometriosis'. Inclusion criteria were: menopausal women with a history of endometriosis and menopausal treatment including HRT or other preparations. Case reports/series, observational studies and clinical trials were included. Narrative review articles, organizational guidelines and conference abstracts were excluded, as were studies that did not report on any form of menopausal management. Articles were assessed for risk of bias and quality using GRADE criteria.

OUTCOMES

We present a synthesis of the existing case reports of endometriosis recurrence or malignant transformation in women undergoing treatment for menopausal symptoms. We highlight common presenting symptoms, potential risk factors and outcomes amongst the studies. Sparse high-quality evidence was identified, with few observational studies and only two randomized controlled trials. Given this paucity of data, no definitive conclusions can be drawn concerning risk.

WIDER IMPLICATIONS

Due to the lack of high-quality studies, it remains unclear how to advise women with a history of endometriosis regarding the management of menopausal symptoms. The absolute risk of disease recurrence and malignant transformation cannot be quantified, and the impact of HRT use on these outcomes is not known. Multicentre randomized trials or large observational studies are urgently needed to inform clinicians and patients alike.

Endometriosis: where are we and where are we going?

Endometriosis currently affects ~5.5 million reproductive-aged women in the U.S. with symptoms such as painful periods (dysmenorrhea), chronic pelvic pain, pain with intercourse (dyspareunia), and infertility. It is defined as the presence of endometrial tissue outside the uterine cavity and is found predominately attached to sites within the peritoneal cavity. Diagnosis for endometriosis is solely made through surgery as no consistent biomarkers for disease diagnosis exist. There is no cure for endometriosis and treatments only target symptoms and not the underlying mechanism(s) of disease. The nature of individual predisposing factors or inherent defects in the endometrium, immune system, and/or peritoneal cavity of women with endometriosis remains unclear. The literature over the last 5 years (2010-2015) has advanced our critical knowledge related to hormones, hormone receptors, immune dysregulation, hormonal treatments, and the transformation of endometriosis to ovarian cancer. In this review, we cover the aforementioned topics with the goal of providing the reader an overview and related references for further study to highlight the progress made in endometriosis research, while concluding with critical areas of endometriosis research that are urgently needed.

Does the Presence of Endometriosis Affect Prognosis of Ovarian Cancer?

Ovarian cancers diagnosed between 2000 and 2013 were examined and cases with and without endometriosis compared. Among 139 epithelial ovarian, there were 49 (35%) with endometriosis and 90 (65%) without endometriosis. Endometriosis associated ovarian cancers were more likely to be confined to the pelvis (54% vs. 9%, p < 0.0001) and lower grade (51% vs. 29%, p = 0.014). Younger age and earlier stage independently predicted the presence of endometriosis (p = 0.0011 and p < 0.0001, respectively). Ovarian cancer patients with endometriosis had improved PFS and OS [(HR = 0.20; 95% CI, 0.09-0.43), (HR = 0.18; 95% CI, 0.04-0.81)], compared to patients without endometriosis; however, endometriosis had no independent prognostic significance.

Targeted next-generation sequencing for molecular diagnosis of endometriosis-associated ovarian cancer

Recent molecular and pathological studies suggest that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), especially of the endometrioid and clear cell subtypes. Accordingly, this study had two cardinal aims: first, to obtain mutation profiles of EAOC from Taiwanese patients; and second, to determine whether somatic mutations present in EAOC can be detected in preneoplastic lesions. Formalin-fixed paraffin-embedded (FFPE) tissues were obtained from ten endometriosis patients with malignant transformation. Macrodissection was performed to separate four different types of cells from FFPE sections in six patients. The four types of samples included normal endometrium, ectopic endometriotic lesion, atypical endometriosis, and carcinoma. Ultra-deep (>1000×) targeted sequencing was performed on 409 cancer-related genes to identify pathogenic mutations associated with EAOC. The most frequently mutated genes were PIK3CA (6/10) and ARID1A (5/10). Other recurrently mutated genes included ETS1, MLH1, PRKDC (3/10 each), and AMER1, ARID2, BCL11A, CREBBP, ERBB2, EXT1, FANCD2, MSH6, NF1, NOTCH1, NUMA1, PDE4DIP, PPP2R1A, RNF213, and SYNE1 (2/10 each). Importantly, in five of the six patients, identical somatic mutations were detected in atypical endometriosis and tumor lesions. In two patients, genetic alterations were also detected in ectopic endometriotic lesions, indicating the presence of genetic alterations in preneoplastic lesion. Genetic analysis in preneoplastic lesions may help to identify high-risk patients at early stage of malignant transformation and also shed new light on fundamental aspects of the molecular pathogenesis of EAOC.

KEY MESSAGES

Molecular characterization of endometriosis-associated ovarian cancer genes by targeted NGS. Candidate genes predictive of malignant transformation were identified. Chromatin remodeling, PI3K-AKT-mTOR, Notch signaling, and Wnt/β-catenin pathway may promote cell malignant transformation.

Endometriosis and ovarian cancer: potential benefits and harms of screening and risk-reducing surgery

Although endometriosis is well recognized as a benign gynecologic condition, its association with ovarian cancer (OVCA) has frequently been reported. Review articles on this topic are voluminous, yet there seems to be no consensus as to whether endometriosis is truly a precursor of OVCA and whether any screening or risk-reducing surgery should be instituted, on the basis of our current knowledge. In this review, published data are compiled and critically appraised. Through this critical appraisal, it seems clear that the strongest evidence seems to come from prevalence data. This type of data also suggests a reduced risk of certain histotypes (mainly type II) of OVCA in women with endometriosis. This may explain the rather moderate increase in risk as shown in epidemiologic studies. Even with this moderate increase in OVCA risk, caution should be exercised because of apparent bias in favor of publication of positive results, extensive heterogeneities among prevalence estimates, and inverse relationship between estimates and sizes of the studies. Many molecular studies are conflicting, and earlier studies showing molecular aberrations involved in genomic instability and mutation that enable malignant transformation are not replicated in later studies. Given the low incidence of OVCA and the rather moderate increase in risk of mostly type I tumors, screening seems to be ill-advised, and risk-reducing surgery such as salpingectomy with or without oophorectomy does not seem to yield any substantial benefit to women with endometriosis.

Novel biomarker candidates for the diagnosis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma can arise from endometriosis; however, it is distinct from other types of epithelial ovarian carcinoma in terms of its clinicopathological and molecular features. Cancer antigen 125 lacks the sensitivity and specificity required for accurate clinical diagnosis of clear cell carcinoma. Therefore, the aim of the current review was to identify novel biomarker candidates for the immunohistochemical and serological diagnosis of clear cell carcinoma. A search of the relevant English language literature published between 1966 and 2014 was conducted using the PubMed MEDLINE online database. High-throughput tissue microarray technology and proteomic screening combined with mass spectrometry may provide additional information regarding diagnostic biomarker candidates for ovarian clear cell carcinoma. The present review summarizes the characteristics of potential genomic alterations that activate cancer signaling pathways and, thus, contribute to carcinogenesis. The major signaling pathways activated in clear cell carcinoma are associated with cell cycle regulation (hepatitis A virus cellular receptor 1 and tumor protein D52), growth factor signaling (insulin-like growth factor binding protein 1; KiSS-1 metastasis-suppressor; erb-b2 receptor tyrosine kinase 2; and fibroblast growth factor receptor 2), anti-apoptosis and survival pathways [sialidase 3 (membrane sialidase)], metabolism (γ-glutamyltransferase 1), chemoresistance (napsin A aspartic peptidase, glutathione peroxidase 3; and aldehyde dehydrogenase 1 family, member A1), coagulation [coagulation factor III (thromboplastin, tissue factor); and tissue factor pathway inhibitor 2], signaling (lectin, galactoside-binding and soluble, 3), and adhesion and the extracellular matrix [cadherin 1, type 1, E-cadherin (epithelial); versican; and laminin, α 5]. The present review of the relevant literature may provide a basis for additional clinical investigation of the ovarian clear cell carcinoma serum biomarker candidate proteins identified herein.

Evaluation of in vitro chemoresponse profiles in women with Type I and Type II epithelial ovarian cancers: An observational study ancillary analysis

OBJECTIVE

Type I epithelial ovarian cancers (EOCs) are reported to be relatively chemoresistant. This study sought to compare pretreatment chemoresponse assays in Type I vs. Type II EOCs.

STUDY DESIGN

383 women with stage III-IV EOC enrolled in an observational study, with known chemoresponse assay results for 7 common therapeutic agents, were included. Type I EOCs were defined as grade 1 serous/endometrioid cancers and all clear cell/mucinous cancers. Type II EOCs were classified as grade 2-3 serous/endometrioid cancers and undifferentiated cancers. Chemotherapy assay responses were classified as sensitive (S), intermediately sensitive (I), or resistant (R). All patients were treated with platinum/taxane therapy following cytoreductive surgery.

RESULTS

Thirty (7.8%) tumors were classified as Type I EOC, and 353 (92.2%) as Type II EOC. Type I patients were younger at the time of diagnosis (median age: 57 vs. 62 years, p=0.018) and had longer survival compared to Type II patients (mPFS: 25.8 vs. 16.4 months, HR=1.71, p=0.042). Eighty-six percent of Type I EOC specimens demonstrated a sensitive chemoresponse assay result to at least 1 agent; 35.7% were pan-S to all 7 agents. After adjusting for stage, debulking status, and type of EOC, multi-drug resistance was twice as likely in women with Type I EOC compared to Type II EOC (pan-R, 14.3% vs. 6.8% (p=0.268); pan-S, 35.7% vs. 51.2% (p=0.183)), but did not attain statistical significance.

CONCLUSION(S)

The majority of women with Type I EOC displayed assay sensitivity to at least one agent. Given the small sample size these findings need to be evaluated further.

Adenocarcinoma of Mullerian origin: review of pathogenesis, molecular biology, and emerging treatment paradigms

Traditionally, epithelial ovarian, tubal, and peritoneal cancers have been viewed as separate entities with disparate origins, pathogenesis, clinical features, and outcomes. Additionally, previous classification systems for ovarian cancer have proposed two primary histologic groups that encompass the standard histologic subtypes. Recent data suggest that these groupings no longer accurately reflect our knowledge surrounding these cancers. In this review, we propose that epithelial ovarian, tubal, and peritoneal carcinomas represent a spectrum of disease that originates in the Mullerian compartment. We will discuss the incidence, classification, origin, molecular determinants, and pathologic analysis of these cancers that support the conclusion they should be collectively referred to as adenocarcinomas of Mullerian origin. As our understanding of the molecular and pathologic profiling of adenocarcinomas of Mullerian origin advances, we anticipate treatment paradigms will shift towards genomic driven therapeutic interventions.

Ovarian cancer: new developments in clear cell carcinoma and hopes for targeted therapy

Until recently, ovarian clear cell carcinoma was recognized by its unique morphology and unfavorable patient outcome primarily due to tumor chemoresistance. Recently, specific molecular characteristics of ovarian clear cell carcinoma, such as PI3CA mutation, ARID1a mutation and MET amplification, have been elucidated. In addition, an association between endometriosis and the tumor has also been a focus of research in recent years. The aim of this review is to discuss the specificity and importance of molecular changes and various intriguing points that are not solved until today. Finally, future aspects, including hopes for the development of novel therapies, are discussed.