Loss of ARID1A/BAF250a-expression in endometriosis: a biomarker for risk of carcinogenic transformation?

Expression patterns of HDAC6 in correlation to ARID1A status in different subtypes of endometriosis: A retrospective tissue microarray analysis

Endometriosis is a disease affecting approximately 10% of reproductive age women. Loss of the tumor suppressor gene AT-rich interactive domain-containing protein 1A (ARID1A) occurs in some endometriosis cases. Histone deacetylase 6 (HDAC-6) is an enzyme with implication in several diseases including different cancer types and immunological disorders, where it is involved in protein trafficking and degradation, cell shape, and migration. In ARID1A-deficient ovarian cancer increased HDAC-6 expression lead to apoptosis-inhibiting post-translational modification of p53. It is not known if HDAC-6 expression is also altered in ARID1A-deficient endometriosis. The aim of this study was to assess HDAC-6 expression in endometriotic lesions in correlation to ARID1A-status. Two tissue-microarrays with 168 endometriotic lesions, including ovarian (64/168, 38 %), peritoneal (66/168, 39 %) and deep-infiltrating (38/168, 23 %) subtypes, and 73 endometrium of women without endometriosis were assessed. Mean ARID1A immunoreactivity score (IRS) in endometriosis group was 10.83 (±2.36) and 10.78 (±1.94) in the epithelium and stroma, respectively, while the respective mean HDAC6 IRS were 9.16 (±2.76) and 5.94 (±2.88). The comparison of the HDAC6 expression between endometriosis subtypes showed higher expression in deep-infiltrating endometriosis, in both, epithelium (p = 0.032) and stroma (p = 0.007). In ARID1A negative cases, epithelial expression of HDAC6 was higher in endometriosis compared to women without endometriosis (p = 0.031), and this was also specifically observed in the subset of ovarian endometriosis (p = 0.037). There were no significant differences in the stromal expression of HDAC6. In conclusion, our results demonstrate a complex expression pattern of HDAC6 depending on ARID1A status in different endometriosis subtypes. Further studies on HDAC6 and ARID1A are important to elucidate mechanisms involved in malignant transformation of endometriosis.

The "Road" to Malignant Transformation from Endometriosis to Endometriosis-Associated Ovarian Cancers (EAOCs): An mTOR-Centred Review

Ovarian cancer is an umbrella term covering a number of distinct subtypes. Endometrioid and clear-cell ovarian carcinoma are endometriosis-associated ovarian cancers (EAOCs) frequently arising from ectopic endometrium in the ovary. The mechanistic target of rapamycin (mTOR) is a crucial regulator of cellular homeostasis and is dysregulated in both endometriosis and endometriosis-associated ovarian cancer, potentially favouring carcinogenesis across a spectrum from benign disease with cancer-like characteristics, through an atypical phase, to frank malignancy. In this review, we focus on mTOR dysregulation in endometriosis and EAOCs, investigating cancer driver gene mutations and their potential interaction with the mTOR pathway. Additionally, we explore the complex pathogenesis of transformation, considering environmental, hormonal, and epigenetic factors. We then discuss postmenopausal endometriosis pathogenesis and propensity for malignant transformation. Finally, we summarize the current advancements in mTOR-targeted therapeutics for endometriosis and EAOCs.

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.

Landscape of chromatin remodeling gene alterations in endometrial carcinoma

OBJECTIVE

Chromatin remodeling genes (CRGs) encode components of epigenetic regulatory mechanisms and alterations in these genes have been identified in several tumor types, including gynecologic cancers. In this study, we sought to investigate the prevalence and clinicopathological associations of CRG alterations in endometrial carcinoma (EC).

METHODS

We performed a retrospective analysis of 660 ECs sequenced using a clinical massively parallel sequencing assay targeting up to 468 genes, including 25 CRGs, and defined the presence of somatic CRG alterations. Clinicopathologic features were obtained for all cases. Immunohistochemical interrogation of ARID1A and PTEN proteins was performed in a subset of samples.

RESULTS

Of the 660 ECs sequenced, 438 (66.4%) harbored CRG alterations covered by our panel. The most commonly altered CRG was ARID1A (46%), followed by CTCF (21%), KMT2D (18%), KMT2B (17%), BCOR (16%), ARID1B (12%) and SMARCA4 (11%). We found that ARID1A genetic alterations were preferentially bi-allelic and often corresponded to altered ARID1A protein expression in ECs. We further observed that ARID1A alterations were often subclonal when compared to PTEN alterations, which were primarily clonal in ECs harboring both mutations. Finally, CRG alterations were associated with an increased likelihood of myometrial and lymphovascular invasion in endometrioid ECs.

CONCLUSION

CRG alterations are common in EC and are associated with clinicopathologic features and likely play a crucial role in EC.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

AP-1 Subunit JUNB Promotes Invasive Phenotypes in Endometriosis

Endometriosis is a disease defined by the presence of abnormal endometrium at ectopic sites, causing pain and infertility in 10% of women. Mutations in the chromatin remodeling protein ARID1A (AT-rich interactive domain-containing protein 1A) have been identified in endometriosis, particularly in the more severe deep infiltrating endometriosis and ovarian endometrioma subtypes. ARID1A has been shown to regulate chromatin at binding sites of the Activator Protein 1 (AP-1) transcription factor, and AP-1 expression has been shown in multiple endometriosis models. Here, we describe a role for AP-1 subunit JUNB in promoting invasive phenotypes in endometriosis. Through a series of knockdown experiments in the 12Z endometriosis cell line, we show that JUNB expression in endometriosis promotes the expression of epithelial-to-mesenchymal transition genes co-regulated by ARID1A including transcription factors SNAI1 and SNAI2, cell adhesion molecules ICAM1 and VCAM1, and extracellular matrix remodelers LOX and LOXL2. In highly invasive ARID1A-deficient endometriotic cells, co-knockdown of JUNB is sufficient to suppress invasion. These results suggest that AP-1 plays an important role in the progression of invasive endometriosis, and that therapeutic inhibition of AP-1 could prevent the occurrence of deep infiltrating endometriosis.

ARID1A-dependent maintenance of H3.3 is required for repressive CHD4-ZMYND8 chromatin interactions at super-enhancers

BACKGROUND

SWI/SNF (BAF) chromatin remodeling complexes regulate lineage-specific enhancer activity by promoting accessibility for diverse DNA-binding factors and chromatin regulators. Additionally, they are known to modulate the function of the epigenome through regulation of histone post-translational modifications and nucleosome composition, although the way SWI/SNF complexes govern the epigenome remains poorly understood. Here, we investigate the function of ARID1A, a subunit of certain mammalian SWI/SNF chromatin remodeling complexes associated with malignancies and benign diseases originating from the uterine endometrium.

RESULTS

Through genome-wide analysis of human endometriotic epithelial cells, we show that more than half of ARID1A binding sites are marked by the variant histone H3.3, including active regulatory elements such as super-enhancers. ARID1A knockdown leads to H3.3 depletion and gain of canonical H3.1/3.2 at ARID1A-bound active regulatory elements, and a concomitant redistribution of H3.3 toward genic elements. ARID1A interactions with the repressive chromatin remodeler CHD4 (NuRD) are associated with H3.3, and ARID1A is required for CHD4 recruitment to H3.3. ZMYND8 interacts with CHD4 to suppress a subset of ARID1A, CHD4, and ZMYND8 co-bound, H3.3+ H4K16ac+ super-enhancers near genes governing extracellular matrix, motility, adhesion, and epithelial-to-mesenchymal transition. Moreover, these gene expression alterations are observed in human endometriomas.

CONCLUSIONS

These studies demonstrate that ARID1A-containing BAF complexes are required for maintenance of the histone variant H3.3 at active regulatory elements, such as super-enhancers, and this function is required for the physiologically relevant activities of alternative chromatin remodelers.

Endometriosis-associated Ovarian Clear Cell Carcinoma: A Special Entity?

Endometriosis is an estrogen-dependent disease, which serves as a precursor of ovarian cancer, especially clear cell carcinoma (OCCC) and endometrial carcinoma. Although micro-environmental factors such as oxidative stress, immune cell dysfunction, inflammation, steroid hormones, and stem cells required for malignant transformation have been found in endometriosis, the exact carcinogenic mechanism remains unclear. Recent research suggest that many putative driver genes and aberrant pathways including ARID1A mutations, PIK3CA mutations, MET activation, HNF-1β activation, and miRNAs dysfunction, play crucial roles in the malignant transformation of endometriosis to OCCC. The clinical features of OCCC are different from other histological types. Patients usually present with a large, unilateral pelvic mass, and occasionally have thromboembolic vascular complications. OCCC patients are easier to be resistant to chemotherapy, have a worse prognosis, and are usually difficult to treat. To improve the survival of OCCC patients, it is necessary to better understand its specific carcinogenic mechanism and explore new treatment strategy, including molecular target.

Molecular dysregulations underlying the pathogenesis of endometriosis

Endometriosis is a crippling disease characterized by the presence of endometrium-like tissue or scar outside the uterine cavity, commonly confined to the peritoneal and serosal surfaces of the pelvic organs. 10-15% of women in reproductive age are estimated to be affected by endometriosis. Most of these patients present with infertility and suffer from pelvic pain. The benign disease rarely progresses to malignancy. Regardless of its high prevalence, the pathogenesis of the disease is not fully understood. Treatment options for endometriosis are limited and are often based on a symptomatic approach. The unavailability of proper diagnostic approaches, fewer therapeutic options, and sparse understanding of molecular alterations are responsible for the continued disease burden. Exploring the molecular elements causing the pathogenesis of endometriosis may lead to a number of breakthroughs in the treatment of the illness, such as the discovery of new biomarkers for diagnosis and therapeutic targets that can be a guide to better prognosis and reduced recurrence. The goal of this review is to provide the reader a critical understanding of the disease by summarizing the genetic, immunological, hormonal, and epigenetic deregulations that support the molecular basis for development of endometriotic cyst, with a special focus on the study models needed to analyze these changes in the endometriotic microenvironment.

Evaluation of SWI/SNF Protein Expression by Immunohistochemistry in Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinomas (OCCC) are known to harbor ARID1A mutations, and several recent studies have described immunohistochemical loss of SMARCA2, SMARCA4, and SMARCB1 in a subset of tumors. We performed ARID1A, SMARCA2, SMARCA4, and SMARCB1 immunohistochemistry on 105 OCCCs to identify possible associations with clinicopathologic features and assess their prognostic value in these tumors. ARID1A, SMARCA4, and SMARCB1 were considered retained if any tumor cell nucleus stained while for SMARCA2, >5% of tumor nuclei were required to be positive. Patients had a mean age of 56 yr and tumors averaged 13 cm in size. Most patients (63%) had stage I tumors with 47% being alive and well, 41% dead from disease, 10% dead from other causes, and 3% alive with disease at last follow-up (mean 72 mo). Tumors showed an admixture of architectural patterns, but papillary was most frequent (49%). Stromal hyalinization was detected in 83% of OCCCs and a background precursor in 78%. High-grade atypia and/or oxyphilic cells were noted in 45% and 29% of tumors, respectively. All OCCCs expressed SMARCA4 and SMARCB1, but the absence of ARID1A was noted in 30% of tumors and SMARCA2 in 8%. ARID1A-retained OCCCs were associated with a dominant tubulocystic or solid pattern, but no other clinicopathologic features reached statistical significance. No switch/sucrose non-fermentable protein expression was predictive of prognosis. Additional studies with known mutational status of these proteins are warranted to better assess their prognostic utility and develop a standardized immunohistochemical scoring system.

Don't be STUMPed: description and management of uncommon pathologies encountered on specimens from benign gynecologic surgery

PURPOSE OF REVIEW

In this review, we aim to describe uncommon pathologies that gynecologic surgeons may reasonably encounter on surgical specimens following benign gynecologic surgery.

RECENT FINDINGS

Herein, we describe uncommon pathologic findings of the uterus (e.g. squamous morular metaplasia, fibroid variants, stromal tumor of uncertain malignant potential), peritoneum and adnexa (e.g. endosalpingiosis, serous tubal intraepithelial carcinoma), endometriosis (e.g. stromal endometriosis, atypical endometriosis), and findings of particular interest in postmenopausal women (e.g. ovarian cortical stromal hyperplasia, tubal metaplasia). The majority of pathologic findings presented in this article are inherently benign, although they can present diagnostic challenges. If properly classified, additional treatment and/or extended follow-up is often not required; exceptions are highlighted.

SUMMARY

The gynecologic surgeon may encounter uncommon pathologies during a career. Inherent diagnostic difficulties, as well as nonstandardized or outdated terminology, can introduce further uncertainty. Whenever such a situation arises, the surgeon and pathologist should discuss the diagnosis to ensure appropriate treatment options.

Somatic Genomic Events in Endometriosis: Review of the Literature and Approach to Phenotyping

In this review, we provide a survey and appraisal of research into somatic genomic events in endometriosis. Methodologies have evolved from conventional cytogenetics to next-generation sequencing, with findings ranging from chromosome imbalances to recurrent somatic cancer driver mutations. Somatic cancer driver mutations have been described in a range of endometriosis lesions, dominated by recurrent mutations in KRAS and PIK3CA as well as loss of PTEN and BAF250a (ARID1A). These somatic events appear to be largely restricted to the endometriosis glandular epithelium. Somatic mutations, particularly PTEN loss, have also been observed in eutopic (uterine) endometrium, although at lower mutant allele frequencies compared with ectopic lesions. Systematic studies of the potential clinical phenotype of these somatic genomic events have yet to be performed. Thus, we propose a framework to investigate the potential clinical phenotype associated with somatic genomic events in endometriosis. Technical requirements include pathology review of histological endometriosis, microdissection for tissue enrichment, orthogonal validation of whole genome/exome sequencing, and a germline sample for confirmation of somatic origin. Clinical requirements include annotation of surgical findings; patient demographics; cross-sectional and prospective data on pain and fertility; consideration of sampling multiple lesions in each patient, mutant allele frequency, and somatic events in the eutopic endometrium; and confirmation of any associations with mechanistic studies. Given the multifactorial nature of endometriosis-associated symptoms, it is likely that somatic events have small (or at most, moderate) effect sizes, and thus careful consideration will have to be given to future study design.

Endometriosis and ovarian cancer risk, an epigenetic connection

Endometriosis is a gynecological disorder that affects 176 million women worldwide and 1 in 10 females in the United States. Endometriosis most often affects women of child-bearing age, with most going undiagnosed. Endometriosis also shares many characteristics common to invasive cancer and has been known to be associated with epithelial ovarian cancer. Ovarian cancer is the 11^th most common cancer among women and over 22,000 new cases will be diagnosed within the next year. Women most commonly diagnosed with this cancer are between the ages of 55–64 years, outside the range of the age of women affected with endometriosis. While no known cause of either disease has been established, epigenetic regulation is thought to play a major role in both. This review focuses on epigenetic changes that occur within each individual disease as well as those that are similar in both, suggesting a possible etiological link between the two diseases.

Endometriosis-associated ovarian carcinomas: insights into pathogenesis, diagnostics, and therapeutic targets-a narrative review

Endometriosis is a benign gynecologic condition affecting up to one woman out of ten of reproductive age. It is defined by the presence of endometrial-like tissue in localizations outside of the uterine cavity. It often causes symptoms such as chronic pain, most frequently associated with the menstrual cycle, and infertility, but may also be oligo- or asymptomatic. There is evidence that some ovarian carcinoma (OC) histotypes, mainly the ovarian clear cell (OCCC) and endometrioid (EnOC) carcinoma, may arise from endometriosis. The most frequent genomic alterations in these carcinomas are mutations in the AT-rich interacting domain containing protein 1A (ARID1A) gene, a subunit of the SWI/SNF chromatin remodeling complex, and alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway, which frequently co-occur. In ARID1A deficient cancers preclinical experimental data suggest different targetable mechanisms including epigenetic regulation, cell cycle, genomic instability, the PI3K/AKT/mTOR pathway, inflammatory pathways, immune modulation, or metabolic alterations as potential precision oncology approaches. Most of these strategies are relying on the concept of synthetic lethality in which tumors deficient in ARID1A are more sensitive to the different compounds. Some of these approaches are currently being or have recently been investigated in early clinical trials. The remarkably frequent occurrence of these mutations in endometriosis-associated ovarian cancer, the occurrence in a relatively young population, and the high proportion of platinum-resistant disease certainly warrants further investigation of precision oncology opportunities in this population. Furthermore, advanced knowledge about oncogenic mutations involved in endometriosis-associated ovarian carcinomas may be potentially useful for early cancer detection. However, this approach may be complicated by the frequent occurrence of somatic mutations in benign endometriotic tissue as recent studies suggest. In this narrative review of the current literature, we will discuss the data available on endometriosis-associated ovarian carcinoma, with special emphasis on epidemiology, diagnosis and molecular changes that could have therapeutic implications and clinical applicability in the future.

ARID1A Mutations Promote P300-Dependent Endometrial Invasion through Super-Enhancer Hyperacetylation

Endometriosis affects 1 in 10 women and is characterized by the presence of abnormal endometrium at ectopic sites. ARID1A mutations are observed in deeply invasive forms of the disease, often correlating with malignancy. To identify epigenetic dependencies driving invasion, we use an unbiased approach to map chromatin state transitions accompanying ARID1A loss in the endometrium. We show that super-enhancers marked by high H3K27 acetylation are strongly associated with ARID1A binding. ARID1A loss leads to H3K27 hyperacetylation and increased chromatin accessibility and enhancer RNA transcription at super-enhancers, but not typical enhancers, indicating that ARID1A normally prevents super-enhancer hyperactivation. ARID1A co-localizes with P300 at super-enhancers, and genetic or pharmacological inhibition of P300 in ARID1A mutant endometrial epithelia suppresses invasion and induces anoikis through the rescue of super-enhancer hyperacetylation. Among hyperactivated super-enhancers, SERPINE1 (PAI-1) is identified as an essential target gene driving ARID1A mutant endometrial invasion. Broadly, our findings provide rationale for therapeutic strategies targeting super-enhancers in ARID1A mutant endometrium.

SWI/SNF inactivation in the endometrial epithelium leads to loss of epithelial integrity

Although ARID1A mutations are a hallmark feature, mutations in other SWI/SNF (SWItch/Sucrose Non-Fermentable) chromatin remodeling subunits are also observed in endometrial neoplasms. Here, we interrogated the roles of Brahma/SWI2-related gene 1 (BRG1, SMARCA4), the SWI/SNF catalytic subunit, in the endometrial epithelium. BRG1 loss affects more than one-third of all active genes and highly overlaps with the ARID1A gene regulatory network. Chromatin immunoprecipitation studies revealed widespread subunit-specific differences in transcriptional regulation, as BRG1 promoter interactions are associated with gene activation, while ARID1A binding is associated with gene repression. However, we identified a physiologically relevant subset of BRG1 and ARID1A co-regulated epithelial identity genes. Mice were genetically engineered to inactivate BRG1 specifically in the endometrial epithelium. Endometrial glands were observed embedded in uterine myometrium, indicating adenomyosis-like phenotypes. Molecular similarities were observed between BRG1 and ARID1A mutant endometrial cells in vivo, including loss of epithelial cell adhesion and junction genes. Collectively, these studies illustrate overlapping contributions of multiple SWI/SNF subunit mutations in the translocation of endometrium to distal sites, with loss of cell integrity being a common feature in SWI/SNF mutant endometrial epithelia.

ARID1A protein expression is retained in ovarian endometriosis with ARID1A loss-of-function mutations: implication for the two-hit hypothesis

ARID1A loss-of-function mutation accompanied by a loss of ARID1A protein expression is considered one of the most important driver events in endometriosis-associated ovarian cancer. Although our recent genomic study clarified that ARID1A loss-of-function mutations were detected in 13% of ovarian endometriosis, an association between the ARID1A mutation status and ARID1A protein expression in ovarian endometriosis remains unclear. We performed immunohistochemical staining for ARID1A in 78 ovarian endometriosis samples and 99 clear cell carcinoma samples. We revealed that not only 70 endometriosis samples without ARID1A mutations but also eight endometriosis samples with ARID1A loss-of-function mutations retained ARID1A protein expression. On the other hand, most of clear cell carcinomas with ARID1A loss-of-function mutations showed a loss of ARID1A protein expression. In particular, clear cell carcinoma samples which harbor multiple ARID1A loss-of-function mutations or both a single ARID1A loss-of-function mutation and ARID1A allelic imbalance lost ARID1A protein expression. However, ARID1A protein expression was retained in seven clear cell carcinomas with ARID1A loss-of-function mutations. These results suggest that a single ARID1A loss-of-function mutation is insufficient for ARID1A loss in ovarian endometriosis and some clear cell carcinoma. Further driver events may be needed for the malignant transformation of ovarian endometriosis with ARID1A loss-of-function mutations.

Loss of ARID1A expression is associated with poor prognosis in non-small cell lung cancer

Adenine-thymine-rich inactive domain-containing protein 1A (ARID1A) is a large subunit of the switch-sucrose nonfermenting (SWI-SNF) complex. ARID1A is considered to be a tumor suppressor in various cancers. We investigated the clinicopathological significance including prognosis of ARID1A expression in non-small cell lung cancer (NSCLC). ARID1A expression was studied by tissue microarray immunohistochemical analysis of 171 surgically resected NSCLC specimens including adenocarcinoma (ADC) and squamous cell carcinoma (SCC) on tissue microarray. Semiquantitative immunohistochemical score was obtained by multiplying the intensity and percentage scores. The overall score was further simplified by dichotomizing into either negative (score < 4) or positive (score ≥ 4) for each patient. The ARID1A-negative group revealed significantly higher correlations with male sex (p = 0.020), larger tumor size (p = 0.007), SCC than with ADC (p = 0.023) and smoking (p = 0.001). Univariate survival analysis showed that the ARID1A-negative group had a significantly shorter cancer specific survival than the ARID1A-positive group (p = 0.018). Multivariate survival analysis showed that ARID1A negativity (p = 0.022) were independent prognostic factors related with shorter cancer specific survival for NSCLC. In conclusion, Loss of ARID1A expression is a potential molecular marker to predictive of poor prognosis of NSCLC.

Pathogenesis of bowel endometriosis

The pathogenesis of bowel endometriosis is multifactorial. There is a predilection for disease of the rectum/sigmoid colon because refluxed endometrium is more likely to settle in the pouch of Douglas and its movement is delimited by the sigmoid colon, in addition to the close proximity of the rectum/sigmoid to posterior extrinsic uterine adenomyosis and to ovarian endometriomas. Once situated, deep bowel endometriosis has features of invasion, angiogenesis, and fibrosis (repeated tissue injury and repair), with emerging research on oxidative stress and the microbiome. Furthermore, deep bowel endometriosis is associated with neurogenesis and/or the recruitment of local nerve fibers and is capable of invading existing nerves, which in turn may also promote fibrosis. Recently, somatic cancer driver mutations (e.g., in KRAS) were identified in deep bowel endometriosis, which may play a role in the genetic/epigenetic theory of endometriosis. In the future, it is possible that bowel endometriosis could be classified based on molecular features.

[Abnormal gut microbiota-induced hypoestrogenemia as a possible risk factor for malignancy in endometrioid heterotopia]

This paper reveals the pathogenetic impact of the abnormal gut microbiota on the development of female reproductive system diseases. A dynamic imbalance between the altered microbiota and the macroorganism has many manifestations as hormonal homeostatic disorders, one of which is dysbiosis-induced hypoestrogenemia. Using endometrioid heterotopia as an example, the authors trace the possibility of its progression and malignancy due to the occurrence of primary breakdown of the PTEN tumor-suppressor gene with subsequent genetic abnormalities in the ARID1A and TP53 genes. PTEN mutation in both endometriosis itself and its malignancy indicates that dysbiosis-induced hypoestrogenemia may be implicated in the pathogenesis of endometriosis. Thus, the relationship between female reproductive system diseases and gut microbiome disorders may be more significant; and the possibility of correcting the gut microbiota with prebiotics and probiotics opens new horizons not only in the prevention, but also in the treatment of many gynecological diseases associated with hormone disorders.

SWI/SNF Complex Mutations in Gynecologic Cancers: Molecular Mechanisms and Models

The SWI/SNF (mating type SWItch/Sucrose NonFermentable) chromatin remodeling complexes interact with histones and transcription factors to modulate chromatin structure and control gene expression. These evolutionarily conserved multisubunit protein complexes are involved in regulating many biological functions, such as differentiation and cell proliferation. Genomic studies have revealed frequent mutations of genes encoding multiple subunits of the SWI/SNF complexes in a wide spectrum of cancer types, including gynecologic cancers. These SWI/SNF mutations occur at different stages of tumor development and are restricted to unique histologic types of gynecologic cancers. Thus, SWI/SNF mutations have to function in the appropriate tissue and cell context to promote gynecologic cancer initiation and progression. In this review, we summarize the current knowledge of SWI/SNF mutations in the development of gynecologic cancers to provide insights into both molecular pathogenesis and possible treatment implications for these diseases.

Wise Management of Ovarian Cancer: On the Cutting Edge

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality among women. Two-thirds of patients present at advanced stage at diagnosis, and the estimated 5 year survival rate is 20-40%. This heterogeneous group of malignancies has distinguishable etiology and molecular biology. Initially, single-gene sequencing was performed to identify germline DNA variations associated with EOC. However, hereditary EOC syndrome can be explained by germline pathogenic variants (gPVs) in several genes. In this regard, next-generation sequencing (NGS) changed clinical diagnostic testing, allowing assessment of multiple genes simultaneously in a faster and cheaper manner than sequential single gene analysis. As we move into the era of personalized medicine, there is evidence that poly (ADP-ribose) polymerase (PARP) inhibitors exploit homologous recombination (HR) deficiency, especially in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers. Furthermore, extensive preclinical data supported the development of aurora kinase (AURK) inhibitors in specific tumor types, including EOC. Their efficacy may be optimized in combination with chemotherapeutic or other molecular agents. The efficacy of metformin in ovarian cancer prevention is under investigation. Certain mutations, such as ARID1A mutations, and alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway, which are specific in ovarian clear cell carcinoma (OCCC) and endometrioid ovarian carcinoma (EnOC), may offer additional therapeutic targets in these clinical entities. Malignant ovarian germ cell tumors (MOGCTs) are rare and randomized trials are extremely challenging for the improvement of the existing management and development of novel strategies. This review attempts to offer an overview of the main aspects of ovarian cancer, catapulted from the molecular mechanisms to therapeutic considerations.

Molecular Classification and Emerging Targeted Therapy in Endometrial Cancer

Recent advances in molecular studies, especially genome-wide analyses, have revealed the landscape of genomic alterations present in endometrial carcinomas, and have provided valuable insight into the pathogenesis of this disease. The current challenges are in developing a molecular-morphologic classification system to enhance traditional pathologic diagnosis and in determining the optimal approach to using this new information to guide clinical management. Molecular assays may be particularly beneficial in allowing the earlier detection of endometrial cancer or precursor lesions and in guiding personalized treatment approaches. In this review, we describe the current molecular landscape of endometrial cancers, efforts underway to incorporate molecular alterations into the current classification systems, and the development of diagnostic tools for the early detection of endometrial cancer. Finally, we present opportunities for using these data to tailor therapeutic strategies. A comprehensive understanding of the molecular alterations responsible for the origination, relapse, and resistance patterns of this disease will ultimately improve outcomes for patients with endometrial cancer.

Association between endometriosis and gynecological cancers: a critical review of the literature

BACKGROUND

Endometriosis is one of the most common benign gynecological diseases with an occurrence approximately 10% in reproductive age. Endometriosis has been proposed as a possible precursor of certain ovarian carcinomas such as clear cell and endometrioid ovarian carcinomas. In addition to this pathogenic link, the association with other gynecological tumors and breast cancer has been studied on an epidemiological basis in several studies.

OBJECTIVE

The aim of this review was to critically present the recent published evidence on the association of endometriosis with gynecological cancer, and with a special emphasis on ovarian cancer.

MATERIALS AND METHODS

A search for eligible studies was conducted in three electronic databases, MEDLINE, EMBASE and CINAHL, for original research in humans published in any language.

RESULTS

The present review includes studies examining the association between endometriosis and different types of gynecological cancer (i.e., 25 studies on ovarian cancer, 8 studies on breast cancer, 8 studies on endometrial cancer and 2 studies on cervical cancer).

CONCLUSION

The present literature supports the pre-existing evidence suggesting an association between ovarian cancer and endometriosis and specifically its two histologic subtypes (endometrioid and ovarian clear cell cancer). The most recent population-based epidemiological studies cannot provide a clear association between endometriosis and endometrial, cervical or breast cancer.

A mouse model of endometriosis mimicking the natural spread of invasive endometrium

STUDY QUESTION

Is it possible to establish a genetically engineered mouse model (GEMM) of endometriosis that mimics the natural spread of invasive endometrium?

SUMMARY ANSWER

Endometriosis occurs in an ARID1A (AT-rich interactive domain-containing protein 1A) and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha) mutant GEMM of endometrial dysfunction following salpingectomy.

WHAT IS KNOWN ALREADY

Although mouse models of endometriosis have long been established, most models rely on intraperitoneal injection of uterine fragments, steroid hormone treatments or the use of immune-compromised mice.

STUDY DESIGN, SIZE, DURATION

Mice harboring the lactotransferrin-Cre (LtfCre0/+), Arid1afl, (Gt)R26Pik3ca*H1047R and (Gt)R26mTmG alleles were subject to unilateral salpingectomies at 6 weeks of age. Control (n = 9), LtfCre0/+; (Gt)R26Pik3ca*H1047R; Arid1afl/+ (n = 8) and LtfCre0/+; (Gt)R26Pik3ca*H1047R; Arid1afl/fl (n = 9) were used for the study. The (Gt)R26mTmG allele was used for the purpose of fluorescent lineage tracing of endometrial epithelium. LtfCre0/+; (Gt)R26mTmG (n = 3) and LtfCre0/+; (Gt)R26Pik3ca*H1047R/mTmG; Arid1afl/fl (n = 4) were used for this purpose. Mice were followed until the endpoint of vaginal bleeding at an average time of 17 weeks of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At 6 weeks of age, mice were subjected to salpingectomy surgery. Mice were followed until the time point of vaginal bleeding (average 17 weeks), or aged for 1 year in the case of control mice. At time of sacrifice, endometriotic lesions, ovaries and uterus were collected for the purpose of histochemical and immunohistochemical analyses. Samples were analyzed for markers of the endometriotic tissue and other relevant biomarkers.

MAIN RESULTS AND THE ROLE OF CHANCE

Following salpingectomy, LtfCre0/+; (Gt)R26Pik3ca*H1047R/mTmG; Arid1afl/fl mice developed endometriotic lesions, including lesions on the ovary, omentum and abdominal wall. Epithelial glands within lesions were negative for ARID1A and positive for phospho-S6 staining, indicating ARID1A-PIK3CA co-mutation status, and expressed EGFP (enhanced green fluorescent protein), indicating endometrial origins.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

LtfCre0/+; (Gt)R26Pik3ca*H1047R; Arid1afl/fl mice develop vaginal bleeding as a result of endometrial dysfunction at an average age of 17 weeks and must be sacrificed. Furthermore, while this model mimics the natural spread of endometriotic tissue directly from the uterus to the peritoneum, the data presented do not reject current hypotheses on endometriosis pathogenesis.

WIDER IMPLICATIONS OF THE FINDINGS

The idea that endometriosis is the result of abnormal endometrial tissue colonizing the peritoneum via retrograde menstruation has gained widespread support over the past century. However, most models of endometriosis take for granted this possibility, relying on the surgical removal of bulk uterine tissue and subsequent transplantation into the peritoneum. Growing evidence suggests that somatic mutations in ARID1A and PIK3CA are present in the endometrial epithelium. The establishment of a GEMM which mimics the natural spread of endometrium and subsequent lesion formation supports the hypothesis that endometriosis is derived from mutant endometrial epithelium with invasive properties.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the American Cancer Society PF-17-163-02-DDC (M.R.W.), the Mary Kay Foundation 026-16 (R.L.C.) and the Ovarian Cancer Research Fund Alliance 457446 (R.L.C.). The authors declare no competing interests.

Loss of ARID1A Expression Correlates With Tumor Differentiation and Tumor Progression Stage in Pancreatic Ductal Adenocarcinoma

Mutations in the AT-rich interactive domain 1A gene, which encodes a subunit of the Switch/Sucrose nonfermentable chromatin remodeling complex, can result in loss of protein expression and are associated with different cancers. Here, we used immunohistochemistry to investigate the significance of AT-rich interactive domain 1A loss in 73 pancreatic ductal adenocarcinoma cases with paired paracancerous normal pancreatic tissues. The relationship between levels of the AT-rich interactive domain 1A protein product, BAF250a, and clinicopathological parameters in the 73 pancreatic cancer specimens was also analyzed. We found that the expression of AT-rich interactive domain 1A in normal pancreatic tissue was higher than that in tumor tissue. Loss of AT-rich interactive domain 1A expression in pancreatic tumors was associated with tumor differentiation (P = .002) and tumor stage (P = .048). Meanwhile, BAF250a protein levels were not related to lymph node metastasis, distant metastasis, sex, or age and were not associated with survival. Transfection of the pancreatic cancer cell lines AsPC-1 and PANC-1 with small-interfering RNA specific for AT-rich interactive domain 1A resulted in elevated messenger RNA and protein expression levels of B-cell lymphoma-2 (Bcl-2), CyclinD1, and Kirsten rat sarcoma viral oncogene (KRAS). The AT-rich interactive domain 1A expression level in the cells was increased following microRNA-31 (miR-31) inhibitor transfection. Our data provide additional evidence that AT-rich interactive domain 1A might function as a tumor suppressor gene in pancreatic carcinogenesis.

Cancer driver mutations in endometriosis: Variations on the major theme of fibrogenesis

BACKGROUND

One recent study reports cancer driver mutations in deep endometriosis, but its biological/clinical significance remains unclear. Since the natural history of endometriosis is essentially gradual progression toward fibrosis, it is thus hypothesized that the six driver genes reported to be mutated in endometriosis (the RP set) may play important roles in fibrogenesis but not necessarily malignant transformation.

METHODS

Extensive PubMed search to see whether RP and another set of driver genes not yet reported (NR) to be mutated in endometriosis have any roles in fibrogenesis. All studies reporting on the role of fibrogenesis of the genes in both RP and NR sets were retrieved and evaluated in this review.

RESULTS

All six RP genes were involved in various aspects of fibrogenesis as compared with only three NR genes. These nine genes can be anchored in networks linking with their upstream and downstream genes that are known to be aberrantly expressed in endometriosis, piecing together seemingly unrelated findings.

CONCLUSIONS

Given that somatic driver mutations can and do occur frequently in physiologically normal tissues, it is argued that these mutations in endometriosis are not necessarily synonymous with malignancy or premalignancy, but the result of enormous pressure for fibrogenesis.

The Endometriotic Tumor Microenvironment in Ovarian Cancer

Women with endometriosis are at increased risk of developing ovarian cancer, specifically ovarian endometrioid, low-grade serous, and clear-cell adenocarcinoma. An important clinical caveat to the association of endometriosis with ovarian cancer is the improved prognosis for women with endometriosis at time of ovarian cancer staging. Whether endometriosis-associated ovarian cancers develop from the molecular transformation of endometriosis or develop because of the endometriotic tumor microenvironment remain unknown. Additionally, how the presence of endometriosis improves prognosis is also undefined, but likely relies on the endometriotic microenvironment. The unique tumor microenvironment of endometriosis is composed of epithelial, stromal, and immune cells, which adapt to survive in hypoxic conditions with high levels of iron, estrogen, and inflammatory cytokines and chemokines. Understanding the unique molecular features of the endometriotic tumor microenvironment may lead to impactful precision therapies and/or modalities for prevention. A challenge to this important study is the rarity of well-characterized clinical samples and the limited model systems. In this review, we will describe the unique molecular features of endometriosis-associated ovarian cancers, the endometriotic tumor microenvironment, and available model systems for endometriosis-associated ovarian cancers. Continued research on these unique ovarian cancers may lead to improved prevention and treatment options.

Heterogeneity of estrogen receptor α and progesterone receptor distribution in lesions of deep infiltrating endometriosis of untreated women or during exposure to various hormonal treatments

Deep infiltrating endometriosis (DIE) responds variably to hormonal therapy. Mutations in cancer driver genes have been identified in a fraction of the ectopic endometrial epithelial cells, suggesting a functional heterogeneity of these lesions. To evaluate the phenotype heterogeneity of cells in DIE, we measured the expression of estrogen receptor α (ERα) and of progesterone receptor (PR) in DIE of untreated women or under various treatments. We analyzed the luminal epithelial height (LEH), immunoreactive epithelial staining (IRS) and stromal staining intensity (SSI) of ERα and PR. We observed a high variability in the same gland, among distinct glands in the same sample and among distinct patients receiving the same treatment. LEH variability was primarily due to epithelial cells heterogeneity in a gland, secondarily to the glands randomly evaluated on the same section, and tertiary to the patient category. Variability in IRS and SSI scores was primarily the consequence of their heterogeneity in the same woman and to a lesser extent to variability among patients. LEH and SSI were not modified according to treatment. IRS for PR was lower in treated patients. This heterogeneity of ERα and PR distribution could explain why endocrine treatments are unable to cure this condition.

Optimised ARID1A immunohistochemistry is an accurate predictor of ARID1A mutational status in gynaecological cancers

ARID1A is a tumour suppressor gene that is frequently mutated in clear cell and endometrioid carcinomas of the ovary and endometrium and is an important clinical biomarker for novel treatment approaches for patients with ARID1A defects. However, the accuracy of ARID1A immunohistochemistry (IHC) as a surrogate for mutation status has not fully been established for patient stratification in clinical trials. Here we tested whether ARID1A IHC could reliably predict ARID1A mutations identified by next-generation sequencing. Three commercially available antibodies - EPR13501 (Abcam), D2A8U (Cell Signaling), and HPA005456 (Sigma) - were optimised for IHC using cell line models and human tissue, and screened across a cohort of 45 gynaecological tumours. IHC was scored independently by three pathologists using an immunoreactive score. ARID1A mutation status was assessed using two independent sequencing platforms and the concordance between ARID1A mutation and protein expression was evaluated using Receiver Operating Characteristic statistics. Overall, 21 ARID1A mutations were identified in 14/43 assessable tumours (33%), the majority of which were predicted to be deleterious. Mutations were identified in 6/17 (35%) ovarian clear cell carcinomas, 5/8 (63%) ovarian endometrioid carcinomas, 2/5 (40%) endometrial carcinomas, and 1/7 (14%) carcinosarcomas. ROC analysis identified greater than 95% concordance between mutation status and IHC using a modified immunoreactive score for all three antibodies allowing a definitive cut-point for ARID1A mutant status to be calculated. Comprehensive assessment of concordance of ARID1A IHC and mutation status identified EPR13501 as an optimal antibody, with 100% concordance between ARID1A mutation status and protein expression, across different gynaecological histological subtypes. It delivered the best inter-rater agreement between all pathologists, as well as a clear cost-benefit advantage. This could allow patients to be accurately stratified based on their ARID1A IHC status into early phase clinical trials.

You won't believe this old test … that does cheap single-cell mutation detection

Detecting mutations in single cells from cancer specimens is now a major area of translational research. In a recent article in this journal, Khalique et al validated an immunohistochemistry assay for ARID1A that reliably identifies loss of function mutations in single cells in tissue sections. This work exemplifies best practice for developing and orthogonally validating immunohistochemical assays to provide clearly interpretable mutational results with spatial context.

Endometriosis-associated Ovarian Cancers

Endometriosis-associated cancers include clear cell and endometrioid ovarian carcinoma. A history of endometriosis has long been considered to be a risk factor for later development of these malignancies; however, recent molecular genetic evidence has provided unequivocal evidence that these lesions are in fact the precursors for endometriosis-associated cancers. Herein, we will explore the relationship between endometriosis and ovarian carcinomas, similarities between the premalignant lesions and their cancerous counterparts, and the potential role of mutations and the ovarian microenvironment that may contribute to malignant transformation.

Prevalence of common polymorphisms of AT-rich interaction domain 1A and endothelial nitric oxide synthase in patients with endometriosis compared to control group

Introduction:

Endometriosis is a common gynecologic disorder defined as ectopic presence of endometrial tissue in extrauterine sites. Endometriosis is associated with infertility and risk of malignancy. Identification of genetic factors responsible for development and malignant transformation of endometriosis can improve therapeutic approaches. In this study, we investigated the association of AT-rich interaction domain 1A ( ARID1A) and endothelial nitric oxide synthase ( eNOS) polymorphisms with endometriosis and staging of the disease.

Methods:

A total of 100 women with laparoscopy-confirmed diagnosis of endometriosis were included and compared with 100 women without endometriosis as the control group. Genotypes of patients regarding Gln920Ter polymorphism of ARID1A gene and Glu298Asp polymorphism of eNOS gene were determined by polymerase chain reaction techniques on blood samples from the study population. The prevalence of each genotype in endometriosis patients was compared with healthy controls using the chi-square test.

Results:

Significantly higher prevalence of non-CC genotype for ARID1A Gln920Ter polymorphism and non-GG genotype for G894T polymorphism of the eNOS gene was detected in the endometriosis group. There was no significant relationship between these polymorphisms and staging of endometriosis.

Discussion:

Significant variation of prevalence of Gln920Ter polymorphism of the ARID1A gene and Glu298Asp polymorphism of the eNOS gene among the two groups can indicate a causative effect of these genetic alterations on the development of endometriosis.

Comprehensive Clinicopathologic and Updated Immunohistochemical Characterization of Primary Ovarian Mucinous Carcinoma

The distinction of primary mucinous ovarian carcinoma (PMOC) from other primaries or secondaries is essential for selecting therapeutic options and prognostication. We aimed to characterize the immunohistochemical profile of 36 PMOCs using an extended immunohistochemical panel, with clinicopathologic features and outcome. PAX8 was negative in 30 (83.3%), and SATB2 was negative in 32/35. HNF1B, AMACR, and napsin-A were detected in 33 (91.7%), 35 (97.2%), and 0 (0%), respectively. MMR proteins and ARID1A were retained in 100%; PTEN was lost in 4 (11.1%). P53 was aberrant in 10 (27.8%); none overexpressed p16. HER2 was positive in 6/35 (17.1%). Most PMOCs had a favorable outcome. However, recurrence is usually fatal. The typical tumor profile was CK7+, CK20+/-, CDX2+/-, PAX8-, ER-, PgR-, and SATB2-. HER2 positivity suggests a possible target for therapy in advanced disease.

The origin of endometriosis-associated ovarian cancer from uterine neoplastic lesions

Endometriosis is a risk factor for type I epithelial ovarian cancer but an issue to be clarified is the site of origin of endometriosis associated ovarian cancer. Here we proposed that the uterus may be the organ of origin of ovarian endometrioid cancer associated with endometriosis. Thus, the first neoplastic transformation would characterize the uterine cells migrating in the pelvis via retrograde menstruation and they would implant secondarily on the ovary. Supporting this hypothesis, an higher incidence of synchronous precancerous and cancerous endometrial pathology in patients affected by ovarian endometrioid cancer associated with endometriosis was showed. Moreover, uterine endometrial type I carcinoma resembles endometriosis associated endometrioid ovarian cancer in behavior and prognosis. This hypothesis is also supported by epidemiologic evidence showing a protective effect for tubal ligation and oral contraceptive use for endometriosis associated endometrioid ovarian cancer. Endometriosis and endometrioid ovarian carcinoma might represent two distinct biological entities characterized by the same organ of origin (the uterus), the same pathogenetic mechanism (transtubal reflux) and the same target organ (the ovary). By shifting the early events of ovarian carcinogenesis to the endometrium, prevention approaches as salpingectomy/tubal ligation and intervention at uterine corpus level may play an important role.

Cancer-Associated Mutations in Endometriosis without Cancer

BACKGROUND

Endometriosis, defined as the presence of ectopic endometrial stroma and epithelium, affects approximately 10% of reproductive-age women and can cause pelvic pain and infertility. Endometriotic lesions are considered to be benign inflammatory lesions but have cancerlike features such as local invasion and resistance to apoptosis.

METHODS

We analyzed deeply infiltrating endometriotic lesions from 27 patients by means of exomewide sequencing (24 patients) or cancer-driver targeted sequencing (3 patients). Mutations were validated with the use of digital genomic methods in microdissected epithelium and stroma. Epithelial and stromal components of lesions from an additional 12 patients were analyzed by means of a droplet digital polymerase-chain-reaction (PCR) assay for recurrent activating KRAS mutations.

RESULTS

Exome sequencing revealed somatic mutations in 19 of 24 patients (79%). Five patients harbored known cancer driver mutations in ARID1A, PIK3CA, KRAS, or PPP2R1A, which were validated by Safe-Sequencing System or immunohistochemical analysis. The likelihood of driver genes being affected at this rate in the absence of selection was estimated at P=0.001 (binomial test). Targeted sequencing and a droplet digital PCR assay identified KRAS mutations in 2 of 3 patients and 3 of 12 patients, respectively, with mutations in the epithelium but not the stroma. One patient harbored two different KRAS mutations, c.35G→T and c.35G→C, and another carried identical KRAS c.35G→A mutations in three distinct lesions.

CONCLUSIONS

We found that lesions in deep infiltrating endometriosis, which are associated with virtually no risk of malignant transformation, harbor somatic cancer driver mutations. Ten of 39 deep infiltrating lesions (26%) carried driver mutations; all the tested somatic mutations appeared to be confined to the epithelial compartment of endometriotic lesions.

Ovarian borderline tumors in the 2014 WHO classification: evolving concepts and diagnostic criteria

Borderline ovarian tumors (BOT) are uncommon but not rare epithelial ovarian neoplasms, intermediate between benign and malignant categories. Since BOT were first identified >40 years ago, they have inspired controversies disproportionate to their incidence. This review discusses diagnostic criteria for the histologic subtypes of BOT, highlighting areas of diagnostic challenges, ongoing controversies, and changes in terminology implemented by the recent 2014 WHO Classification of Tumours of the Female Genital Organs. Emerging knowledge supports the notion that subtypes of borderline ovarian tumors comprise distinct biologic, pathogenetic, and molecular entities, precluding a single unifying concept for BOT. Serous borderline tumors (SBT) share molecular and genetic alterations with low-grade serous carcinomas and can present at higher stages with peritoneal implants and/or lymph node involvement, which validates their borderline malignant potential. All other (non-serous) subtypes of BOT commonly present at stage I confined to the ovary(ies) and are associated with overall survival approaching that of the general population. An important change in the WHO 2014 classification is the new terminology of non-invasive implants associated with SBT, as any invasive foci (previously called “invasive implants”) are now in line with their biological behavior considered peritoneal low-grade serous carcinoma (LGSC). The controversy regarding the terminology of non-serous borderline tumors, called by some pathologists “atypical proliferative tumor” in view of their largely benign behavior, has not been resolved. The concepts of intraepithelial carcinoma and microinvasion may evolve in further studies, as their presence appears to have no prognostic impact and is subject to considerable inter-observer variability.

Effect of ARID1A/BAF250a expression on carcinogenesis and clinicopathological factors in pure-type clear cell adenocarcinoma of the ovary

Frequent mutation of the ARID1A gene has been recently identified in ovarian clear-cell adenocarcinoma (CCA); however, the clinical significance of BAF250a expression encoded by the ARID1A gene remains to be determined. The aim of the present study was to assess whether BAF250a expression had an impact on the clinical features of CCA. A total of 97 cases of CCA treated at a single institution were enrolled in the present study. The tissue samples were evaluated by immunohistochemical staining. BAF250a-deficient expression was observed in 30% (29/97) of all CCA cases. Of this, 19% of non-atypical endometriosis, 26% of atypical endometriosis, 39% of endometriosis-related CCA, 5% of benign clear-cell adenofibroma (CCAF), 5% of borderline CCAF and 10% of CCAF-related CCA. BAF250a-deficient expression was significantly more frequent in endometriosis-related CCA compared with that in CCAF-related CCA (P=0.02). No significant difference was observed in the response rate of primary chemotherapy according to BAF250a expression status (P=0.48). Additionally, BAF250a expression status was not significantly correlated with progression-free and overall survival in patients with CCA. Although loss of BAF250a expression was associated with early tumorigenesis in endometriosis-related CCA, this alteration was not significantly correlated with chemosensitivity and prognoses of CCA. Further biomarker analyses, including BAF250a expression, are required to improve the prognoses of CCA.

Low expression of ARID1A correlates with poor prognosis in intrahepatic cholangiocarcinoma

AIM: To investigate the relationship between ARID1A expression and clinicopathologic parameters, as well as its prognostic value, for patients with intrahepatic cholangiocarcinoma (IHCC).

METHODS: We assessed ARID1A protein and mRNA expression in IHCC tissues and paracarcinomatous (PC) tissues from 57 patients with IHCC using western blot and quantitative real-time reverse transcription polymerase chain reaction, respectively. We used Fisher’s exact and χ² tests to analyze relationships between clinicopathological parameters and ARID1A expression. The Kaplan-Meier method and Cox regression were used to analyze survival.

RESULTS: The mean ARID1A protein level in IHCC tissues was 1.16 ± 0.36 relative units (RU), which was significantly lower than that in PC tissues (1.26 ± 0.21 RU, P < 0.01) and NL tissues (1.11 ± 0.31, P < 0.001). The mean ARID1A mRNA level in IHCC tissues (1.20 ± 0.18) was also lower than that in PC tissues (1.27 ± 0.15, P < 0.001) and normal liver tissues (1.15 ± 0.34, P < 0.001). Low ARID1A expression was significantly associated with tumor nodules, vein invasion, and recurrence. Median overall survival (OS) and disease-free survival (DFS) for the low ARID1A expression group was 15.0 and 7.0 mo, respectively, which were significantly shorter than those for the high ARID1A expression group at 25.0 and 22.0 mo (OS: P < 0.01; DFS: P < 0.001), respectively. Low ARID1A expression was significantly associated with worse OS (HR = 3.967, 95%CI: 1.299-12.118, P = 0.016) in multivariate analyses.

CONCLUSION: Low expression of ARID1A is associated with poor prognosis in patients with IHCC, and thus may be a potential prognostic biomarker candidate in IHCC.

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.

Molecular pathogenesis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma is a distinct subtype of epithelial ovarian cancer, characterized by an association with endometriosis, glycogen accumulation and resistance to chemotherapy. Key driver events, including ARID1A mutations and HNF1B overexpression, have been recently identified and their functional characterization is ongoing. Additionally, the role of glycogen in promoting the malignant phenotype is coming under scrutiny. Appreciation of the notion that ovarian clear cell carcinoma is essentially an ectopic uterine cancer will hopefully lead to improved animal models of the disease, in turn paving the way for effective treatments.

(Partial) Loss of BAF250a (ARID1A) in rectovaginal deep-infiltrating endometriosis, endometriomas and involved pelvic sentinel lymph nodes

STUDY HYPOTHESIS

Loss of protein BAF250a (ARID1A) expression is present in women with rectovaginal deep-infiltrating endometriosis (DIE) and endometriosis affecting the pelvic sentinel lymph nodes (PSLN).

STUDY FINDING

Partial loss of protein BAF250a was found in some of our patient samples, comprising all endometriosis entities, including rectovaginal DIE and endometriosis affecting the PSLN.

WHAT IS KNOWN ALREADY

Loss of BAF250a (BRG-associated factor 250a)/ARIDIA (AT-rich interactive domain 1A) protein expression was identified among endometriosis-associated ovarian carcinomas and ovarian endometriosis, and this phenomenon was described as a possible early event in the transformation of endometriosis into cancer. DIE affecting the bowel/rectovaginal site is the most aggressive presentation of endometriosis and its 'risk' of malignant transformation has not been studied so far.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We evaluated the immunohistochemical expression of BAF250a protein in 70 samples from patients enrolled in this study who were surgically treated at a tertiary center, university Hospital. The samples submitted to investigation were from rectovaginal DIE (n= 25/30), endometriosis affecting the PSLN (n= 5/7), ovarian endometriosis (n= 20/20) and endometrium from patients without endometriosis used as controls (n= 20/20).

MAIN RESULTS AND THE ROLE OF CHANCE

Partial loss (i.e. in one tissue section some cells stained positive for BAF250a while other cells, usually an adjacent group, were negative) of BAF250a protein was identified in 36% (9/25) of rectovaginal DIE samples, 40% (2/5) of endometriosis lesions involving the PSLN, 30% (6/20) of endometriomas, and also in 25% (5/20) of endometrium from controls. We found no statistical correlation between occurrence of partial loss of BAF250a protein and the use or not of hormone medications (P = 0.106), cycle phase (P = 0.917) and stage of disease (P = 0.717).

LIMITATIONS, REASONS FOR CAUTION

We only found partial loss of BAF250a protein expression, and in a small population of women, with relatively high frequency in all benign tissues assessed in the present analysis. Therefore, this finding alone should not be correlated directly with the risk of malignant transformation in these lesions.

WIDER IMPLICATIONS OF THE FINDINGS

The occurrence of partial loss of BAF250a protein expression in women with rectovaginal DIE and endometriosis affecting the PSLN is described for the first time. The value of this finding as a predictor of malignant transformation in endometriosis must still be clarified and further studied in association with other molecular events, such as PTEN (phosphatase and tensin homolog) deletion and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) mutation. We might then be able to identify in the future which patients with endometriosis are at higher risk of cancer.

STUDY FUNDING AND COMPETING INTERESTS

This study was supported by an internal Charité grant to the Endometriosis Research Center and the authors declare no conflicts of interest.

Immunohistochemical Investigation of Metastasis-Related Chemokines in Deep-Infiltrating Endometriosis and Compromised Pelvic Sentinel Lymph Nodes

Endometriosis is a prevalent benign disease, despite sharing several similarities with malignancies, such as the possibility of lymphatic spread. In malignancies, chemokines play a sovereign role in the process of metastasis. Metastasis-related chemokine axes have not yet been assessed in deep-infiltrating endometriosis (DIE), and this investigation was the aim of our study. The expression of these chemokines was investigated by immunohistochemistry in rectovaginal DIE lesions and in matched pelvic sentinel lymph nodes (PSLNs) of patients with endometriosis (n = 27), and their expression in the eutopic endometrium (EE) of endometriosis-free women (n = 20) was used as controls. Their staining pattern in rectovaginal DIE, in endometriotic lesions affecting the PSLN as well as in the EE of patients without endometriosis was characterized for the first time. Overall, these chemokines were highly expressed in DIE and endometriosis in PSLN. Chemokines might be involved in the spread of endometriosis and should be further investigated.