Clinicopathologic Significance of HNF-1β, AIRD1A, and PIK3CA Expression in Ovarian Clear Cell Carcinoma: A Tissue Microarray Study of 130 Cases

Genome-wide DNA methylation in relation to ARID1A deficiency in ovarian clear cell carcinoma

BACKGROUND

The poor chemo-response and high DNA methylation of ovarian clear cell carcinoma (OCCC) have attracted extensive attentions. Recently, we revealed the mutational landscape of the human kinome and additional cancer-related genes and found deleterious mutations in ARID1A, a component of the SWI/SNF chromatin-remodeling complex, in 46% of OCCC patients. The present study aims to comprehensively investigate whether ARID1A loss and genome-wide DNA methylation are co-regulated in OCCC and identify putative therapeutic targets epigenetically regulated by ARID1A.

METHODS

DNA methylation of ARID1Amt/ko and ARID1Awt OCCC tumors and cell lines were analyzed by Infinium MethylationEPIC BeadChip. The clustering of OCCC tumors in relation to clinical and mutational status of tumors were analyzed by hierarchical clustering analysis of genome-wide methylation. GEO expression profiles were used to identify differentially methylated (DM) genes and their expression level in ARID1Amt/ko vs ARID1Awt OCCCs. Combining three pre-ranked GSEAs, pathways and leading-edge genes epigenetically regulated by ARID1A were revealed. The leading-edge genes that passed the in-silico validation and showed consistent ARID1A-related methylation change in tumors and cell lines were regarded as candidate genes and finally verified by bisulfite sequencing and RT-qPCR.

RESULTS

Hierarchical clustering analysis of genome-wide methylation showed two clusters of OCCC tumors. Tumor stage, ARID1A/PIK3CA mutations and TP53 mutations were significantly different between the two clusters. ARID1A mutations in OCCC did not cause global DNA methylation changes but were related to DM promoter or gene-body CpG islands of 2004 genes. Three pre-ranked GSEAs collectively revealed the significant enrichment of EZH2- and H3K27me3-related gene-sets by the ARID1A-related DM genes. 13 Leading-edge DM genes extracted from the enriched gene-sets passed the expression-based in-silico validation and showed consistent ARID1A-related methylation change in tumors and cell lines. Bisulfite sequencing and RT-qPCR analysis showed promoter hypermethylation and lower expression of IRX1, TMEM101 and TRIP6 in ARID1Amt compared to ARID1Awt OCCC cells, which was reversed by 5-aza-2'-deoxycytidine treatment.

CONCLUSIONS

Our study shows that ARID1A loss is related to the differential methylation of a number of genes in OCCC. ARID1A-dependent DM genes have been identified as key genes of many cancer-related pathways that may provide new candidates for OCCC targeted treatment.

New insights about endometriosis-associated ovarian cancer: pathogenesis, risk factors, prediction and diagnosis and treatment

Previous studies have shown that the risk of malignant transformation of endometriosis in premenopausal women is approximately 1%, significantly impacting the overall well-being and quality of life of affected women. Presently, the diagnostic gold standard for endometriosis-associated ovarian cancer (EAOC) continues to be invasive laparoscopy followed by histological examination. However, the application of this technique is limited due to its high cost, highlighting the importance of identifying a non-invasive diagnostic approach. Therefore, there is a critical need to explore non-invasive diagnostic methods to improve diagnostic precision and optimize clinical outcomes for patients. This review presents a comprehensive survey of the current progress in comprehending the pathogenesis of malignant transformation in endometriosis. Furthermore, it examines the most recent research discoveries concerning the diagnosis of EAOC and emphasizes potential targets for therapeutic intervention. The ultimate objective is to improve prevention, early detection, precise diagnosis, and treatment approaches, thereby optimizing the clinical outcomes for patients.

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.

Clinical analysis and literature review of a case of ovarian clear cell carcinoma with PIK3CA gene mutation: A case report

RATIONALE

Ovarian clear cell carcinoma (OCCC) is an uncommon malignant form of 5 subtypes of ovarian cancer, accounting for approximately 5% to 25% of all ovarian cancers. OCCC is usually diagnosed at a young age and an early stage. More than 50% of patients are associated with endometriosis. It shows less sensitivity to platinum-based chemotherapies, high recurrence, and poor prognosis, especially late. However, platinum-based chemotherapies remain the first-line treatment. Meanwhile, new treatment modalities have been explored, including immune checkpoint inhibitors and PI3K-AKT-mTOR pathway inhibitors.

PATIENT CONCERN

A 48-year-old Chinese woman, Gravida2 Para1, complained of irregular and painful vaginal bleeding for 4 months.

DIAGNOSIS

The patient was diagnosed with stage IC ovarian clear cell carcinoma that presented with a mutation of the phosphatidylinositol 4,5-bisphosphate 3-kinase alpha subunit (PIK3CA) gene.

INTERVENTION

We performed an early diagnosis and complete surgical resection of the tumor with platinum-based chemotherapy.

OUTCOME

This patient with mutation of the PIK3CA gene was sensitive to platinum-based chemotherapy, showed a significant downwards trend in tumor markers, and was in good health within the year of follow-up.

LESSONS

This study described an OCCC case that presented with a PIK3CA mutation and was successfully managed with careful and complete resection of the tumor. This patient with mutation of the PIK3CA gene was sensitive to platinum-based chemotherapy, showed a significant downwards trend in tumor markers, and did not have recurrence after a year of follow-up, indicating a reasonably good prognosis. Therefore, surgery plus platinum drug chemotherapy is still the best strategy for OCCC treatment. In addition, it is recommended for such patients to undergo genetic testing as much as possible to predict the clinical treatment effect.

GLS1 is a protective factor in patients with ovarian clear cell carcinoma and its expression does not correlate with ARID1A-mutated tumors

Targeting glutamine metabolism has emerged as a novel therapeutic strategy for several human cancers, including ovarian cancer. The primary target of this approach is the kidney isoform of glutaminase, glutaminase 1 (GLS1), a key enzyme in glutamine metabolism that is overexpressed in several human cancers. A first-in-class inhibitor of GLS1, called CB839 (Telaglenastat), has been investigated in several clinical trials, with promising results. The first clinical trial of CB839 in platinum-resistant ovarian cancer patients is forthcoming. ARID1A-mutated ovarian clear cell carcinoma (OCCC) is a relatively indolent and chemoresistant ovarian cancer histotype. In OCCC-derived cells ARID1A simultaneously drives GLS1 expression and metabolism reprograming. In ARID1A-mutated OCCC-derived mouse models, loss of ARID1A corresponds to GLS1 upregulation and increases sensitivity to GLS1 inhibition. Thus, targeting of GLS1 with CB839 has been suggested as a targeted approach for OCCC patients with tumors harboring ARID1A-mutations. Here, we investigated whether GLS1 is differentially expressed between OCCC patients whose tumors are ARID1A positive and patients whose tumors are ARID1A negative. In clinical specimens of OCCC, we found that GLS1 overexpression was not correlated with ARID1A loss. In addition, GLS1 overexpression was associated with better clinical outcomes. Our findings have implications for human trials using experimental therapeutics targeting GLS1.

Validated biomarker assays confirm that ARID1A loss is confounded with MMR deficiency, CD8+ TIL infiltration, and provides no independent prognostic value in endometriosis-associated ovarian carcinomas

ARID1A (BAF250a) is a component of the SWI/SNF chromatin modifying complex, plays an important tumour suppressor role, and is considered prognostic in several malignancies. However, in ovarian carcinomas there are contradictory reports on its relationship to outcome, immune response, and correlation with clinicopathological features. We assembled a series of 1623 endometriosis-associated ovarian carcinomas, including 1078 endometrioid (ENOC) and 545 clear cell (CCOC) ovarian carcinomas, through combining resources of the Ovarian Tumor Tissue Analysis (OTTA) Consortium, the Canadian Ovarian Unified Experimental Resource (COEUR), local, and collaborative networks. Validated immunohistochemical surrogate assays for ARID1A mutations were applied to all samples. We investigated associations between ARID1A loss/mutation, clinical features, outcome, CD8+ tumour-infiltrating lymphocytes (CD8+ TILs), and DNA mismatch repair deficiency (MMRd). ARID1A loss was observed in 42% of CCOCs and 25% of ENOCs. We found no associations between ARID1A loss and outcomes, stage, age, or CD8+ TIL status in CCOC. Similarly, we found no association with outcome or stage in endometrioid cases. In ENOC, ARID1A loss was more prevalent in younger patients (p = 0.012) and was associated with MMRd (p < 0.001) and the presence of CD8+ TILs (p = 0.008). Consistent with MMRd being causative of ARID1A mutations, in a subset of ENOCs we also observed an association with ARID1A loss-of-function mutation as a result of small indels (p = 0.035, versus single nucleotide variants). In ENOC, the association with ARID1A loss, CD8+ TILs, and age appears confounded by MMRd status. Although this observation does not explicitly rule out a role for ARID1A influence on CD8+ TIL infiltration in ENOC, given current knowledge regarding MMRd, it seems more likely that effects are dominated by the hypermutation phenotype. This large dataset with consistently applied biomarker assessment now provides a benchmark for the prevalence of ARID1A loss-of-function mutations in endometriosis-associated ovarian cancers and brings clarity to the prognostic significance. © 2021 The Pathological Society of Great Britain and Ireland.

Targeting the IRE1α/XBP1 Endoplasmic Reticulum Stress Response Pathway in ARID1A-Mutant Ovarian Cancers

The SWI/SNF chromatin-remodeling complex is frequently altered in human cancers. For example, the SWI/SNF component ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCC), for which effective treatments are lacking. Here, we report that ARID1A transcriptionally represses the IRE1α-XBP1 axis of the endoplasmic reticulum (ER) stress response, which confers sensitivity to inhibition of the IRE1α-XBP1 pathway in ARID1A-mutant OCCC. ARID1A mutational status correlated with response to inhibition of the IRE1α-XBP1 pathway. In a conditional Arid1a^flox/flox/Pik3ca^H1047R genetic mouse model, Xbp1 knockout significantly improved survival of mice bearing OCCCs. Furthermore, the IRE1α inhibitor B-I09 suppressed the growth of ARID1A-inactivated OCCCs in vivo in orthotopic xenograft, patient-derived xenograft, and the genetic mouse models. Finally, B-I09 synergized with inhibition of HDAC6, a known regulator of the ER stress response, in suppressing the growth of ARID1A-inactivated OCCCs. These studies define the IRE1α-XBP1 axis of the ER stress response as a targetable vulnerability for ARID1A-mutant OCCCs, revealing a promising therapeutic approach for treating ARID1A-mutant ovarian cancers. SIGNIFICANCE: These findings indicate that pharmacological inhibition of the IRE1α-XBP1 pathway alone or in combination with HDAC6 inhibition represents an urgently needed therapeutic strategy for ARID1A-mutant ovarian cancers.

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.

Mismatch repair deficiency is associated with specific morphologic features and frequent loss of ARID1A expression in ovarian clear cell carcinoma

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is the second subtype of ovarian epithelial carcinoma reported to be closely related to Lynch syndrome (LS). ARID1A mutation is an important pathogenetic mechanism in OCCC that leads to loss of ARID1A expression in approximately half of OCCCs. However, the correlation of MMR status and ARID1A deficiency is unclear. The current study aimed to identify the clinical and histopathological characteristics of OCCC associated with dMMR and to further explore the association between dMMR and ARID1A deficiency.

METHODS

A cohort of 176 primary OCCC patients was enrolled and review included histological characteristics (nuclear atypia, necrosis, mitosis, stromal hyalinization, and background precursors) and host inflammatory response (tumor-infiltrating lymphocytes, peritumoral lymphocytes, intratumoral stromal inflammation and plasma cell infiltration). Immunohistochemical staining of MLH1, PMS2, MSH2, MSH6 and ARID1A was performed using tissue microarrays.

RESULTS

dMMR was detected in 10/176 tumors (6 %), followed by MSH2/MSH6 (6/176), MLH1/PMS2 (3/176), and MSH6 (1/176). The average age of patients with dMMR was younger than that of patients with intact MMR (46 y vs. 53 y). Tumors with diffuse intratumoral stromal inflammation remained significantly associated after multivariate analysis. ARID1A expression was absent in 8 patients with dMMR (8/10), which is a significantly higher frequency than that observed in patients with intact MMR (80 % vs. 43.2 %).

CONCLUSIONS

Our study indicates that diffuse intratumoral stromal inflammation of OCCCs is associated with dMMR, with loss of MSH2/MSH6 expression being most frequent. dMMR is strongly associated with the loss of ARID1A expression in OCCC.

Clinical perspectives of BET inhibition in ovarian cancer

BACKGROUND

Bromodomain and extra-terminal (BET) proteins are epigenetic readers that bind to acetylated lysines of histones and regulate gene transcription. BET protein family members mediate the expression of various oncogenic drivers in ovarian cancer, such as the MYC and Neuregulin 1 (NRG1) genes. BRD4, the most thoroughly studied member of the BET family, is amplified in a significant subset of high-grade serous carcinomas (HGSC) of the ovary. It has been reported that BET inhibitors can attenuate the proliferation and dissemination of ovarian cancer cells by inhibiting oncogenic pathways, such as the FOXM1 and JAK/STAT pathways. BET inhibition can re-sensitize resistant ovarian cancer cells to already approved anticancer agents, including cisplatin and PARP inhibitors. This synergism was also confirmed in vivo in animal models. These and other preclinical results provide a promising basis for the application of BET inhibitors in ovarian cancer treatment. Currently, Phase I/II clinical trials explore the safety and efficacy profiles of BET inhibitors in various solid tumors, including ovarian tumors. Here, we review current knowledge on the molecular effects and preclinical activities of BET inhibitors in ovarian tumors.

CONCLUSIONS

BET proteins have emerged as new druggable targets for ovarian cancer. BET inhibitors may enhance antitumor activity when co-administered with conventional treatment regimens. Results from ongoing Phase I/II studies are anticipated to confirm this notion.

Repurposing Pan-HDAC Inhibitors for ARID1A-Mutated Ovarian Cancer

ARID1A , a subunit of the SWI/SNF complex, is among the most frequently mutated genes across cancer types. ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCCs), diseases that have no effective therapy. Here, we show that ARID1A mutation confers sensitivity to pan-HDAC inhibitors such as SAHA in ovarian cancers. This correlated with enhanced growth suppression induced by the inhibition of HDAC2 activity in ARID1A-mutated cells. HDAC2 interacts with EZH2 in an ARID1A status-dependent manner. HDAC2 functions as a co-repressor of EZH2 to suppress the expression of EZH2/ARID1A target tumor suppressor genes such as PIK3IP1 to inhibit proliferation and promote apoptosis. SAHA reduced the growth and ascites of the ARID1A-inactivated OCCCs in both orthotopic and genetic mouse models. This correlated with a significant improvement of survival of mice bearing ARID1A-mutated OCCCs. These findings provided preclinical rationales for repurposing FDA-approved pan-HDAC inhibitors for treating ARID1A-mutated cancers.

Anti-tumor activity of dual inhibition of phosphatidylinositol 3-kinase and MDM2 against clear cell ovarian carcinoma

INTRODUCTION

PI3K pathway signaling has received attention as a molecular target in clear cell ovarian carcinoma (CCOC). MDM2 is one of the AKT effectors in the PI3K pathway, which binds to and degrades p53. In this study, we aimed to clarify the prognostic significance of PIK3CA and MDM2 expression, and potential therapeutic effect of a dual inhibition of the PI3K pathway and MDM2.

MATERIALS AND METHODS

cDNA expression was evaluated by using microarray data using 75 samples of CCOC. DS-7423 (dual inhibitor of pan-PI3K and mTOR) and RG7112 (MDM2 inhibitor) were used on CCOC cell lines to evaluate cell proliferation, expression level of MDM2 related proteins, and apoptosis by MTT assay, western blotting, and flow cytometry. DS-7423 (3 mg/kg) and/or RG7112 (50 mg/kg) were orally administrated every day for three weeks, and the anti-tumor effect was evaluated using tumor xenografts, along with immunohistochemistry.

RESULTS

Tumors with high expression of both PIK3CA and MDM2 showed significantly worse prognosis in expression array of 71 CCOCs (P = 0.013). Dual inhibition of the PI3K pathway by DS-7423 and MDM2 by RG7112 showed synergistic anti-proliferative effect in 4 CCOC cell lines without TP53 mutations. The combination therapy more robustly induced pro-apoptotic proteins (PUMA and cleaved PARP) with increase of sub G1 population and apoptotic cells, compared with either single agent alone. The combination therapy significantly reduced tumor volume in mice (P < 0.001 in OVISE, and P = 0.038 in RMG-I) without severe body weight loss. Immunohistochemistry from the xenograft tumors showed that the combination treatment significantly reduced vascularity and cell proliferation, with an increase of apoptotic cell death.

CONCLUSION

A combination therapy targeting the PI3K pathway and MDM2 might be a promising therapeutic strategy in CCOC.

SWI/SNF Complexes in Ovarian Cancer: Mechanistic Insights and Therapeutic Implications

Ovarian cancer remains the most lethal gynecologic malignancy in the developed world. Despite the unprecedented progress in understanding the genetics of ovarian cancer, cures remain elusive due to a lack of insight into the mechanisms that can be targeted to develop new therapies. SWI/SNF chromatin remodeling complexes are genetically altered in approximately 20% of all human cancers. SWI/SNF alterations vary in different histologic subtypes of ovarian cancer, with ARID1A mutation occurring in approximately 50% of ovarian clear cell carcinomas. Given the complexity and prevalence of SWI/SNF alterations, ovarian cancer represents a paradigm for investigating the molecular basis and exploring therapeutic strategies for SWI/SNF alterations. This review discusses the recent progress in understanding SWI/SNF alterations in ovarian cancer and specifically focuses on: (i) ARID1A mutation in endometriosis-associated clear cell and endometrioid histologic subtypes of ovarian cancer; (ii) SMARCA4 mutation in small cell carcinoma of the ovary, hypercalcemic type; and (iii) amplification/upregulation of CARM1, a regulator of BAF155, in high-grade serous ovarian cancer. Understanding the molecular underpinning of SWI/SNF alterations in different histologic subtypes of ovarian cancer will provide mechanistic insight into how these alterations contribute to ovarian cancer. Finally, the review discusses how these newly gained insights can be leveraged to develop urgently needed therapeutic strategies in a personalized manner.

ARID1A mutant ovarian clear cell carcinoma: A clear target for synthetic lethal strategies

SWI/SNF chromatin remodeling complexes play an important role in the epigenetic regulation of chromatin structure and gene transcription. Mutual exclusive subunits in the SWI/SNF complex include the DNA targeting members ARID1A and ARID1B as well as the ATPases SMARCA2 and SMARCA4. SWI/SNF complexes are mutated across many cancer types. The highest mutation incidence is found in ARID1A, primarily consisting of deleterious mutations. Current advances have reported synthetic lethal interactions with the loss of ARID1A in several cancer types. In this review, we discuss targets that are only important for tumor growth in an ARID1A mutant context. We focus on synthetic lethal strategies with ARID1A loss in ovarian clear cell carcinoma, a cancer with the highest ARID1A mutation incidence (46-57%). ARID1A directed lethal strategies that can be exploited clinically include targeting of the DNA repair proteins PARP and ATR, and the epigenetic factors EZH2, HDAC2, HDAC6 and BRD2.

Alpha-fetoprotein-producing ovarian clear cell adenocarcinoma with fetal gut differentiation: a rare case report and literature review

Background

Alpha-fetoprotein (AFP) is a useful tumor marker for ovarian germ cell tumors, particularly yolk sac tumor (YST). It is valuable for both diagnosis and further follow-up. Epithelial ovarian carcinoma (EOC) rarely secretes AFP, especially for clear cell type and in the postmenopausal women. Based on the limited knowledge about AFP-producing clear cell type EOC, a case and literature review on this topic is extensively reviewed.

Case presentation

We report a 55-year-old postmenopausal woman experienced vaginal spotting for one month, and serum level of AFP was 60,721 ng/ml initially. Histological examination was clear cell type EOC. Tumor cells revealed strong immunoreactivity for glypican-3 (GPC3) and AFP and weak for hepatocyte nuclear factor-1 beta (HNF-1 beta), but negative for CD30, making the diagnosis of AFP-producing clear cell type EOC with fetal gut differentiation in focal areas, FIGO (International Federation of Gynecology and Obstetrics) IIIc. Although the patient underwent an intensive treatment, including optimal debulking surgery and multi-agent chemotherapy, the patient died of disease. To provide a better understanding of clinical and molecular characteristics of the AFP-producing clear cell type EOC, we conducted a systematic literature review.

Conclusions

A total of three papers described the AFP-producing clear cell type EOC are available. The overall survival rate of these cases, including the current case is 50%. Although immunohistochemical examination is not always needed in routine for the diagnosis of clear cell type EOC, to distinguish from other tumors, especially germ cell tumors, or to provide the better way to monitor therapeutic response or to evaluate the disease status, immunostaining, including GPC3, HNF-1 beta, CD30, cytokeratin 7 or 20, and AFP is taken into account. Due to rarity, the appropriate chemotherapy regimen and the biological behavior of AFP-producing clear cell type EOC are still unclear.

The Role of Oxidative Stress and Membrane Transport Systems during Endometriosis: A Fresh Look at a Busy Corner

Endometriosis is a condition characterized by the presence of endometrial tissue outside the uterine cavity, leading to a chronic inflammatory reaction. It is one of the most widespread gynecological diseases with a 10-15% prevalence in the general female population, rising up to 30-45% in patients with infertility. Although it was first described in 1860, its etiology and pathogenesis are still unclear. It is now accepted that inflammation plays a central role in the development and progression of endometriosis. In particular, it is marked by an inflammatory process associated with the overproduction of an array of inflammatory mediators such as prostaglandins, metalloproteinases, cytokines, and chemokines. In addition, the growth and adhesion of endometrial cells in the peritoneal cavity due to reactive oxygen species (ROS) and free radicals lead to disease onset, its ensuing symptoms-among which pain and infertility. The aim of our review is to evaluate the role of oxidative stress and ROS in the pathogenesis of endometriosis and the efficacy of antioxidant therapy in the treatment and mitigation of its symptoms.

Expression of protein disulfide isomerase family members correlates with tumor progression and patient survival in ovarian cancer

Objective

Protein disulfide isomerase (PDI) is an oxidoreductase that is overexpressed in several cancers. PDI family members (PDIs) play a role in various diseases including cancer. Select PDIs were reported as useful markers in other cancers but their expression in ovarian cancer has not been thoroughly assessed. We sought to evaluate the expression of PDI, PDIA6, PDIR, ERp57, ERp72 and AGR3 in ovarian cancer patient samples and examine their prognostic significance.

Methods

TMA samples from 415 tissues collected from three cancer centers (UM, USC, and KCCRI) were used to assess the expression levels of PDI family proteins using IHC.

Results

We observed significant increases in PDI (p = 9.16E-36), PDIA6 (p = 5.51E-33), PDIR (p = 1.81E-12), ERp57 (p = 9.13E-07), ERp72 (p = 3.65E-22), and AGR3 (p = 4.56E-24) expression in ovarian cancers compared to normal tissues. Expression of PDI family members also increases during disease progression (p <0.001). All PDI family members are overexpressed in serous ovarian cancer (p<0.001). However, PDI, PDIA6, PDIR, ERp72 and AGR3 are more significantly overexpressed (p<0.001) than ERp57 (p<0.05) in clear cell ovarian carcinoma. Importantly, overexpression of PDI family members is associated with poor survival in ovarian cancer (p = 0.045 for PDI, p = 0.047 for PDIR, p = 0.037 for ERp57, p = 0.046 for ERp72, p = 0.040 for AGR3) with the exception of PDIA6 (p = 0.381).

Conclusions

Our findings demonstrate that select PDI family members (PDI, PDIR, ERp72, ERp57 and AGR3) are potential prognostic markers for ovarian cancer.

Clinical implication for endometriosis associated with ovarian cancer

We reviewed current literature regarding the association of endometriosis and epithelial ovarian cancer based on epidemiology studies, molecular researches and clinical observations. Our methods include a review of literature research of MEDLINE, PubMed, Cochrane Library of Systematic Reviews and reference search in selected papers. The life time risk of epithelial ovarian cancer in women with endometriosis is low, yet there might be a cluster of individuals who have higher risk of developing epithelial ovarian cancer from endometriosis. Endometriosis associated ovarian cancer (EAOC) is predominant in particular histological subtypes of epithelial ovarian carcinoma and are related to some specific molecular aberrations. Clinical observations showed age as an important variable to the development of EAOC. Rapid growth of tumor and solid components in sonography are key features to detect malignant transformation of endometriosis. Evidence is not clear about prophylactic oophorectomy in preventing EAOC in patients with endometriosis. This review provided rationale data for identifying, monitoring, counseling and management of women with endometriosis who are potentially high risk for malignant transformation.

ARID1A-mutated ovarian cancers depend on HDAC6 activity

ARID1A , encoding a subunit of the SWI/SNF chromatin-remodelling complex, is the most frequently mutated epigenetic regulator across all human cancers. ARID1A and TP53 mutations are typically mutually exclusive. Therapeutic approaches that correlate with this genetic characteristic remain to be explored. Here, we show that HDAC6 activity is essential in ARID1A-mutated ovarian cancers. Inhibition of HDAC6 activity using a clinically applicable small molecule inhibitor significantly improved the survival of mice bearing ARID1A-mutated tumours. This correlated with the suppression of growth and dissemination of ARID1A-mutated, but not wildtype, tumours. The dependence on HDAC6 activity in ARID1A-mutated cells correlated with a direct transcriptional repression of HDAC6 by ARID1A. HDAC6 inhibition selectively promoted apoptosis of ARID1A-mutated cells. HDAC6 directly deacetylates Lys-120 of p53, a pro-apoptotic post-translational modification. Thus, ARID1A mutation inactivates p53’s apoptosis-promoting function by upregulating HDAC6. Together, these results indicate that pharmacological inhibition of HDAC6 is a therapeutic strategy for ARID1A-mutated cancers.

Whole-genome sequencing revealed novel prognostic biomarkers and promising targets for therapy of ovarian clear cell carcinoma

Background:

Ovarian clear cell carcinoma (OCCC) is mostly resistant to standard chemotherapy that results in poor patient survival. To understand the genetic background of these tumours, we performed whole-genome sequencing of OCCC tumours.

Methods:

Tumour tissue samples and matched blood samples were obtained from 55 Japanese women diagnosed with OCCC. Whole-genome sequencing was performed using the Illumina HiSeq platform according to standard protocols.

Results:

Alterations to the switch/sucrose non-fermentable (SWI/SNF) subunit, the phosphatidylinositol-3-kinase (PI3K)/Akt signalling pathway, and the receptor tyrosine kinase (RTK)/Ras signalling pathway were found in 51%, 42%, and 29% of OCCC tumours, respectively. The 3-year overall survival (OS) rate for patients with an activated PI3K/Akt signalling pathway was significantly higher than that for those with inactive pathway (91 vs 40%, hazard ratio 0.24 (95% confidence interval (CI) 0.10–0.56), P=0.0010). Similarly, the OS was significantly higher in patients with the activated RTK/Ras signalling pathway than in those with the inactive pathway (91 vs 53%, hazard ratio 0.35 (95% CI 0.13–0.94), P=0.0373). Multivariable analysis revealed that activation of the PI3K/Akt and RTK/Ras signalling pathways was an independent prognostic factor for patients with OCCC.

Conclusions:

The PI3K/Akt and RTK/Ras signalling pathways may be potential prognostic biomarkers for OCCC patients. Furthermore, our whole-genome sequencing data highlight important pathways for molecular and biological characterisations and potential therapeutic targeting in OCCC.

Prognostic and Clinicopathological Significance of ARID1A in Endometrium-Related Gynecological Cancers: A Meta-Analysis

The tumor suppressor gene, AT Rich Interactive Domain 1A (ARID1A) mutation has been reported in a variety of cancers, especially the endometrium-related gynecological cancers, including the ovarian clear cell carcinoma, ovarian endometrioid carcinoma, and uterine endometrioid carcinoma. However, the prognostic value of ARID1A in endometrium-related gynecological cancers is still inconclusive. Therefore, we performed this meta-analysis to evaluate the clinical significance of ARID1A in endometrium-related gynecological cancers. By systematically searching all the relevant studies from Pubmed, Cochrane Library, and Web of Science up to September 2016, 11 studies with 1,432 patients were included. All the study characteristics and the prognostic data were extracted. Hazard ratios (HRs) and 95% confidence intervals (CIs) were pooled using the fixed-effect or random-effect model. Our results indicated that negative ARID1A expression predicted shorter Progression free survival (PFS, HR, 1.84; 95%CI, 1.32-2.57, P = 0.000) of patients with endometrium related gynecological cancers, especially the patiently with OCCC and the patients in Japan. Besides, a marginal trend towards the same direction was found in the Overall analysis (OS, HR, 1.34; 95%CI, 0.93-1.93, P = 0.112). Furthermore, the significant correlation was achieved between the negative ARID1A expression and the FIGO stage of endometrium-related gynecological cancers, but not the other characteristics. J. Cell. Biochem. 118: 4517-4525, 2017. © 2017 Wiley Periodicals, Inc.

Ovarian Clear Cell Carcinoma Sub-Typing by ARID1A Expression

PURPOSE

Loss of AT-rich DNA-interacting domain 1A (ARID1A) has been identified as a driving mutation of ovarian clear cell carcinoma (O-CCC), a triple-negative ovarian cancer that is intermediary between serous and endometrioid subtypes, in regards to molecular and clinical behaviors. However, about half of O-CCCs still express BAF250a, the protein encoded by ARID1A. Herein, we aimed to identify signatures of ARID1A-positive O-CCC in comparison with its ARID1A-negative counterpart.

MATERIALS AND METHODS

Seventy cases of O-CCC were included in this study. Histologic grades and patterns of primary tumor, molecular marker immunohistochemistry profiles, and clinical outcomes were analyzed.

RESULTS

Forty-eight (69%) O-CCCs did not express BAF250a, which were designated as "ARID1A-negative." The other 22 (31%) O-CCCs were designated as "ARID1A-positive." ARID1A-positive tumors were more likely to be histologically of high grades (41% vs. 10%, p=0.003), ERβ-positive (45% vs. 17%, p=0.011), and less likely to be HNF1β-positive (77% vs. 96%, p=0.016) and E-cadherin-positive (59% vs. 83%, p=0.028) than ARID1A-negative tumors. Patient age, parity, tumor stage were not significantly different in between the two groups. Cancer-specific survival was not significantly different either.

CONCLUSION

We classified O-CCCs according to ARID1A expression status. ARID1A-positive O-CCCs exhibited distinct immunohistochemical features from ARID1A-negative tumors, suggesting a different underlying molecular event during carcinogenesis.