Clear cell carcinoma of the ovary: a report from the first Ovarian Clear Cell Symposium, June 24th, 2010

Characterization of ovarian clear cell carcinoma using target drug-based molecular biomarkers: implications for personalized cancer therapy

BACKGROUND

It has long been appreciated that different subtypes (serous, clear cell, endometrioid and mucinous) of epithelial ovarian carcinoma (EOC) have distinct pathogenetic pathways. However, clinical management, especially chemotherapeutic regimens, for EOC patients is not subtype specific. Ovarian clear cell carcinoma (CCC) is a rare histological subtype of EOC, which exhibits high rates of recurrence and low chemosensitivity. We assessed potential therapeutic targets for ovarian CCC patients through analyzing the variation of drug-based molecular biomarkers expression between ovarian CCC and high-grade serous carcinoma (HGSC).

METHODS

Seven candidate drug-based molecular biomarkers, human epidermal growth factor receptor (EGFR), human epidermal growth factor receptor-2 (HER2), phosphatase and tensin homolog deleted on chromosome ten (PTEN), aurora kinase A (AURKA), breast cancer susceptibility gene 1 (BRCA1), breast cancer susceptibility gene 2 (BRCA2) and programmed death-ligand 1 (PD-L1) were measured in 96 ovarian CCC and 113 HGSC by immunohistochemistry in paraffin embedded tissues. The relationship between these biomarkers and clinicopathological factors were explored.

RESULTS

The expression level of four of the seven drug-based molecular biomarkers was markedly different between HGSC and CCC. High expression levels of HER2 and PD-L1 were more commonly observed in CCC patients (12.6% vs 2.7%, 21.1% vs 11.6%, P = 0.006, 0.064, respectively), while loss of BRCA1 and BRCA2 expression were more frequently occurred in HGSC patients (72.6% vs 54.3%, 89.4% vs 79.8%, P = 0.007, 0.054, respectively). Survival analysis showed that five of seven biomarkers had prognostic values but varied between subtypes. Furthermore, EGFR expressed frequently in CCC patients with endometriosis than in HGSC patients (44.4% vs 8.3%, P = 0.049). AURKA and PD-L1 correlated with the resistance to platinum-based chemotherapy in CCC patients (P = 0.043, 0.028, respectively) while no similar results were observed in HGSC patients.

CONCLUSION

Ovarian CCC showed a markedly different expression map of drug-based molecular biomarkers from HGSC, which suggested a new personalized target therapy in this rare subtype.

Three versus six cycles of adjuvant platinum-based chemotherapy in early stage clear cell ovarian carcinoma - A multi-institutional cohort

OBJECTIVES

To determine if 6 versus 3cycles of adjuvant platinum-based chemotherapy with or without taxane impacts survival in early stage ovarian clear cell carcinoma (OCCC).

METHODS

We retrospectively identified all cases of stage I and II OCCC treated at 5 institutions from January 1994 through December 2011. Patients were divided into 2 groups: those who received 3 versus 6cycles of adjuvant chemotherapy. Our cohort consisted of 210 patients with stage IA-II disease, 116 of whom underwent full surgical staging. Cox proportional hazards regression and Kaplan-Meier analyses were performed to evaluate progression-free (PFS) and overall survival (OS) between groups.

RESULTS

Among 210 eligible patients, the median age was 53years (range 30-88). The majority of patients were Caucasian (83.8%). All patients received adjuvant chemotherapy with 90% receiving carboplatin and paclitaxel. Thirty-eight (18.1%) patients received 3cycles, and 172 (81.9%) patients received 6cycles of adjuvant treatment. Recurrence rate was comparable between groups (18.4% vs. 27.3% for 3 vs. 6cycles, p=0.4). There was no impact of 3 versus 6cycles of chemotherapy on PFS (hazard ratio [HR] 1.4; 95% confidence interval [CI] 0.63-3.12, p=0.4) or OS (HR 1.65; 95% CI 0.59-4.65, p=0.3) on univariate analysis. There was no benefit to more chemotherapy in stratified analysis by stage nor on multivariate analysis adjusting for the impact of stage. Subgroup analysis of surgically staged patients also showed no difference in survival between 3 versus 6cycles of chemotherapy.

CONCLUSIONS

Three cycles of platinum with or without taxane adjuvant chemotherapy were comparable to 6cycles with respect to recurrence and survival in patients diagnosed with early stage ovarian clear cell carcinoma in this retrospective multi-institutional cohort.

CONDENSATION

Three cycles of platinum with or without taxane adjuvant chemotherapy are comparable to 6 cycles with respect to recurrence and survival in patients diagnosed with early stage ovarian clear cell carcinoma in this retrospective multi-institutional cohort.

Possible de novo clear cell carcinoma in the contralateral ovary 9 years after fertility-sparing surgery for Stage IA clear cell ovarian carcinoma

A patient who underwent fertility-sparing surgery for Stage IA clear cell carcinoma may have developed de novo clear cell carcinoma in the contralateral ovary 9 years later. She underwent fertility-sparing surgery and postoperative adjuvant chemotherapy for right ovarian carcinoma at 33 years of age (when endometriosis was observed in the contralateral ovary). At the age of 41 years, a tumor was discovered in the left ovary. This was diagnosed pathologically as clear cell carcinoma with clear cell adenofibroma, which may have developed de novo. A consensus is currently taking shape that although fertility-sparing surgery is a therapeutic option for patients with Stage IA clear cell carcinoma, long-term outpatient monitoring is advised to watch for its recurrence or de novo development in the contralateral ovary.

Pregnane X receptor, constitutive androstane receptor and hepatocyte nuclear factors as emerging players in cancer precision medicine

Great research effort has been focused on elucidating the contribution of host genetic variability on pharmacological outcomes in cancer. Nuclear receptors have emerged as mediators between environmental stimuli and drug pharmacokinetics and pharmacodynamics. The pregnane X receptor, constitutive androstane receptor and hepatocyte nuclear factors have been reported to regulate transcription of genes that encode drug metabolizing enzymes and transporters. Altered nuclear receptor expression has been shown to affect the metabolism and pharmacological profile of traditional chemotherapeutics and targeted agents. Accordingly, polymorphic variants in these genes have been studied as pharmacogenetic markers of outcome variability. This review summarizes the state of knowledge about the roles played by pregnane X receptor, constitutive androstane receptor and hepatocyte nuclear factor expression and genetics as predictive markers of anticancer drug toxicity and efficacy, which can improve cancer precision medicine.

Structural and calorimetric studies demonstrate that the hepatocyte nuclear factor 1β (HNF1β) transcription factor is imported into the nucleus via a monopartite NLS sequence

The transcription factor hepatocyte nuclear factor 1β (HNF1β) is ubiquitously overexpressed in ovarian clear cell carcinoma (CCC) and is a potential therapeutic target. To explore potential approaches that block HNF1β transcription we have identified and characterised extensively the nuclear localisation signal (NLS) for HNF1β and its interactions with the nuclear protein import receptor, Importin-α. Pull-down assays demonstrated that the DNA binding domain of HNF1β interacted with a spectrum of Importin-α isoforms and deletion constructs tagged with eGFP confirmed that the HNF1β (229)KKMRRNR(235) sequence was essential for nuclear localisation. We further characterised the interaction between the NLS and Importin-α using complementary biophysical techniques and have determined the 2.4Å resolution crystal structure of the HNF1β NLS peptide bound to Importin-α. The functional, biochemical, and structural characterisation of the nuclear localisation signal present on HNF1β and its interaction with the nuclear import protein Importin-α provide the basis for the development of compounds targeting transcription factor HNF1β via its nuclear import pathway.

Clear Cell Adenocarcinofibroma Ovary - A Rare Histopathological Variant with Unusual Presentation

The clear cell adenocarcinoma of ovary is a distinctive tumour. Stroma rich variants (adenocarcinofibroma) of these types of tumours are uncommon. We report a rare case of clear cell adenocarcinofibroma of ovary in 37 years of female presenting with bilateral ovarian masses. The tumour contained fibrous component and was radiologically indistinguishable from soft tissue malignancy. The serum level of CA-125 was raised. Histopathology and immunohistochemistry revealed the rare microscopic type of ovarian tumour. Because of differences in the clinical course as well as management, possibility of this unusual type of carcinoma must be ruled out.

Magnetic resonance imaging for distinguishing ovarian clear cell carcinoma from high-grade serous carcinoma

BACKGROUND

To compare the magnetic resonance imaging (MRI) features of ovarian clear cell carcinoma (CCC) and high-grade serous carcinoma (HGSC), to distinguish CCC from HGSC.

METHODS

MRI features (laterality, shape, size, configuration, papillary projection, signal intensity, enhancement, peritoneal implant, lymphadenopathy, ascites) of 40 tumors in 37 patients with CCC, confirmed by surgery and pathology, were compared with those of 62 tumors in 40 patients with HGSC. Statistical analysis was performed using Mann-Whitney and Fisher's exact tests.

RESULTS

There was a statistically significant difference in the mean maximum diameter, laterality, and FIGO stage (P = 0.002, P < 0.001, P < 0.001, respectively) between CCC and HGSC. Compared to HGSCs, CCCs were more frequently oval (30/40, 75 % vs 12/62, 19 %; P < 0.001), more often cystic (21/40, 53 % vs 8/62, 13 %; P < 0.001) and unilocular (23/29, 79 % vs 7/31, 23 %; P < 0.001), had T1-hyperintense cystic components more often (18/29, 62 % vs 5/29, 17 %; P < 0.001), had larger papillary projections (5.13 ± 0.4 cm vs 2.91 ± 0.3 cm; P < 0.001), were peritoneally implanted less frequently (P = 0.001) and had fewer ascites (P < 0.001).

CONCLUSIONS

CCC typically showed an oval, unilocular cystic mass with large papillary projection and T1-hyperintense cystic components. MRI could be helpful for distinguishing CCC from HGSC.

Synthetic Lethal Targeting of ARID1A-Mutant Ovarian Clear Cell Tumors with Dasatinib

New targeted approaches to ovarian clear cell carcinomas (OCCC) are needed, given the limited treatment options in this disease and the poor response to standard chemotherapy. Using a series of high-throughput cell-based drug screens in OCCC tumor cell models, we have identified a synthetic lethal (SL) interaction between the kinase inhibitor dasatinib and a key driver in OCCC, ARID1A mutation. Imposing ARID1A deficiency upon a variety of human or mouse cells induced dasatinib sensitivity, both in vitro and in vivo, suggesting that this is a robust synthetic lethal interaction. The sensitivity of ARID1A-deficient cells to dasatinib was associated with G1-S cell-cycle arrest and was dependent upon both p21 and Rb. Using focused siRNA screens and kinase profiling, we showed that ARID1A-mutant OCCC tumor cells are addicted to the dasatinib target YES1. This suggests that dasatinib merits investigation for the treatment of patients with ARID1A-mutant OCCC. Mol Cancer Ther; 15(7); 1472-84. ©2016 AACR.

Ovarian Cancer in Hereditary Cancer Susceptibility Syndromes

Hereditary breast and ovarian cancer (HBOC) syndrome and Lynch syndrome (LS) are associated with increased risk of developing ovarian carcinoma. Patients with HBOC have a lifetime risk of up to 50% of developing high-grade serous carcinoma of tube or ovary; patients with LS have a 10% lifetime risk of developing endometrioid or clear cell carcinoma of the ovary. Testing all patients with tubo-ovarian high-grade serous carcinoma for mutations associated with HBOC syndrome, and all patients presenting with endometrioid or clear cell carcinoma of the ovary for mutations associated with LS can identify patients with undiagnosed underlying hereditary cancer susceptibility syndromes.

Clear cell carcinoma of the ovary: molecular insights and future therapeutic perspectives

Clear cell carcinoma (CCC) of the ovary is known to show poorer sensitivity to chemotherapeutic agents and to be associated with a worse prognosis than the more common serous adenocarcinoma or endometrioid adenocarcinoma. To improve the survival of patients with ovarian CCC, the deeper understanding of the mechanism of CCC carcinogenesis as well as the efforts to develop novel treatment strategies in the setting of both front-line treatment and salvage treatment for recurrent disease are needed. In this presentation, we first summarize the mechanism responsible for carcinogenesis. Then, we highlight the promising therapeutic targets in ovarian CCC and provide information on the novel agents which inhibit these molecular targets. Moreover, we discuss on the cytotoxic anti-cancer agents that can be best combined with targeted agents in the treatment of ovarian CCC.

BAG3-mediated Mcl-1 stabilization contributes to drug resistance via interaction with USP9X in ovarian cancer

Paclitaxel in combination with carboplatin improves survival among patients with susceptible ovarian cancers, but no strategy has been established against resistant ovarian cancers. BAG3 (Bcl-2-associated athanogene 3) is one of six BAG family proteins, which are involved in such cellular processes as proliferation, migration and apoptosis. In addition, expression of BAG3 with Mcl-1, a Bcl-2 family protein, reportedly associates with resistance to chemotherapy. Our aim in this study was to evaluate the functional role of BAG3 and Mcl-1 in ovarian cancer chemoresistance and explore possible new targets for treatment. We found that combined expression of BAG3 and Mcl-1 was significantly associated with a poor prognosis in ovarian cancer patients. In vitro, BAG3 knockdown in ES2 clear ovarian cancer cells significantly increased the efficacy of paclitaxel in combination with the Mcl-1 antagonist MIM1, with or without the Bcl-2 family antagonist ABT737. Moreover, BAG3 was found to positively regulate Mcl-1 levels by binding to and inhibiting USP9X. Our data show that BAG3 and Mcl-1 are key mediators of resistance to chemotherapy in ovarian cancer. In BAG3 knockdown ES2 clear ovarian cancer cells, combination with ABT737 and MIM1 enhanced the efficacy of paclitaxel. These results suggest that inhibiting BAG3 in addition to anti-apoptotic Bcl-2 family proteins may be a useful therapeutic strategy for the treatment of chemoresistant ovarian cancers.

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

Ovarian clear cell carcinoma (CCC) is a distinct histologic subtype with relatively poor survival. No prognostic or predictive molecular marker is currently available. Recent studies have shown that AT-rich interactive domain 1A (ARID1A) and phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) mutations are common genetic changes in ovarian CCC. Hepatocyte nuclear factor-1β (HNF-1β) expression has been proven to be highly sensitive and specific for clear cell histology. However, the correlations between these biomarkers and clinicopathologic variables and survival outcomes are controversial. The immunohistochemical analysis for HNF-1β, ARID1A, and PIK3CA was performed on a tissue microarray (TMA) consisting of 130 cases of ovarian CCC (237 tissue blocks) linked with clinical information. The immunostaining results were interpreted in a manner consistent with previous publications. The associations between biomarker expression and clinical and prognostic features were examined. All statistical analyses were conducted using 2-sided tests, and a value of P < 0.05 was considered significant. HNF-1β was expressed in 92.8% of all primary ovarian tumors, while the loss of ARID1A and PIK3CA was noted in 56.2% and 45.0%, respectively. Early-stage tumors tended to have high levels of HNF-1β immunoreactivity and expression of ARID1A (P = 0.02 and P = 0.03). Most patients (76.9%, 20/26) with concurrent endometriosis stained negative for ARID1A (P = 0.02). No relation was found between PIK3CA expression and clinical features. Low-level HNF-1β expression and loss of ARID1A were more commonly observed in patients with tumor recurrence (P = 0.02 and P < 0.001). Antibody expression was not associated with platinum-based chemotherapy response. Patients with negative ARID1A expression had worse survival outcome in terms of both overall survival (OS) and progression-free survival (PFS) (P = 0.03 and P = 0.01, respectively). On the contrary, patients with high-level HNF-1β were associated with good prognosis (P = 0.02 for OS and P = 0.01 for PFS). PIK3CA expression had no impact on survival. For univariate and multivariate analyses, only HNF-1β expression seemed to be a prognostic factor for favorable OS (P = 0.04). The loss of ARID1A was correlated with late-stage and endometriosis-associated tumors. The measurement of ARID1A expression might be a method to predict the risk of recurrence. Among the 3 biomarkers, only high-level HNF-1β expression proved to be a positive predictor for OS.

[Dualistic classification of epithelial ovarian cancer: Is it clinically relevant?]

Malignant epithelial tumors (carcinomas) are the most common ovarian cancers and the most lethal gynecological malignancies. Based on their heterogeneous morphology, a dualistic model of carcinogenesis was proposed in 2004. Type I carcinomas, composed of low grade serous, endometrioid, mucinous, clear cell carcinomas and malignant Brenner tumors, were distinct from type II carcinomas (high grade serous, undifferentiated carcinomas and carcinosarcomas). However, clinical studies failed to demonstrate the prognostic value of such a classification. The main reproach to this dualistic model was that it lumped together in type I tumors, heterogeneous lesions such as clear cell and mucinous carcinomas. Recent advances on molecular genetic alterations and precursor lesions favor the classification of ovarian carcinomas as five distinct diseases. The dualistic model of carcinogenesis in type I and II can finally be applied only to serous ovarian carcinomas (low grade and high grade).

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.

Clear cell carcinomas of the ovary: a mono-institutional study of 73 cases in China with an analysis of the prognostic significance of clinicopathological parameters and IMP3 expression

Background

Ovarian clear cell carcinoma (CCC) is an uncommon subtype of ovarian epithelial tumor. The prognostic significance of its clinicopathological parameters is discordant, with the exception of stage as the adverse prognostic factor. The present study aimed to evaluate the prognostic significance of its clinicopathological characteristics and the expression of IMP3 (Insulin-like growth factor-II mRNA-binding protein 3, IMP3 or IGF2BP3) in Chinese patients with primary pure CCC.

Methods

We collected clinicopathological data from 73 cases with a minimum of 5 years of follow-up and evaluated the expression of IMP3 by immunohistochemistry.

Results

In total, 49.3 % of the patients were in stage I. Advanced stages were closely related to poor prognosis of disease-free survival (DFS) and overall survival (OS) (P < 0.005). Patients with CCC coexisting with endometriosis tended to be younger and to have unilateral involvement but did not exhibit differences in prognosis compared with patients with CCC without endometriosis. Other histological features such as growth pattern, mitosis, and necrosis did not have prognostic significance. IMP3 was positive in 63 % of patients (46 of 73 cases); Thus, positive expression of IMP3 is an adverse prognostic marker in terms of OS (P = 0.012), even in stage I patients (P = 0.038).

Conclusions

The present study demonstrates that IMP3 expression is a prognostic marker, with the exception of stage. IMP3 represents a biomarker of unfavorable prognosis even in stage I patients.

Morphologic and Molecular Characteristics of Mixed Epithelial Ovarian Cancers

Epithelial ovarian cancer (EOC) consists of 5 major histotypes: high-grade serous carcinoma (HGSC), endometrioid carcinoma (EC), clear cell carcinoma (CCC), mucinous carcinoma (MC), and low-grade serous carcinoma (LGSC). Each can have a broad spectrum of morphologic appearances, and 1 histotype can closely mimic histopathologic features more typical of another. Historically, there has been a relatively high frequency of mixed, defined by 2 or more distinct histotypes present on the basis of routine histopathologic assessment, histotype carcinoma diagnoses (3% to 11%); however, recent immunohistochemical (IHC) studies identifying histotype-specific markers and allowing more refined histotype diagnoses suggest a much lower incidence. We reviewed hematoxylin and eosin-stained slides from 871 cases of EOC and found the frequency of mixed carcinomas to be 1.7% when modern diagnostic criteria are applied. Through international collaboration, we established a cohort totaling 22 mixed EOCs, consisting of 9 EC/CCC, 4 EC/LGSC, 3 HGSC/CCC, 2 CCC/MC, and 4 other combinations. We interrogated the molecular differences between the different components of each case using IHC, gene expression, and hotspot sequencing analyses. IHC data alone suggested that 9 of the 22 cases were not mixed tumors, as they presented a uniform immuno-phenotype throughout, and these cases most probably represent morphologic mimicry and variation within tumors of a single histotype. Synthesis of molecular data further reduces the incidence of mixed carcinomas. On the basis of these results, true mixed carcinomas with both morphologic and molecular support for the presence of >1 histotype within a given tumor represent <1% of EOCs.

Potential targets for ovarian clear cell carcinoma: a review of updates and future perspectives

Advances in surgical and medical treatments for ovarian cancer have improved prognoses. Platinum drugs in particular are pivotal for the medical treatment of ovarian cancer. However, previous studies have revealed that some histological subtypes, such as clear cell carcinoma, are resistant to medical treatment, including that with platinum drugs. Consequently, the clinical prognosis of advanced clear cell carcinoma is remarkably inferior, primarily because of its chemoresistant behavior. The prevalence of clear cell carcinoma is approximately 5 % in the West, but in Japan, its prevalence is particularly high, at approximately 25 %. Current medical treatments for advanced clear cell carcinoma are difficult to administer, and they have poor efficacy, warranting the development of novel target-based therapies. In this review, we describe medical treatments for clear cell carcinoma and discuss future prospects for therapy. In particular, we focus on the mechanism of platinum resistance in clear cell carcinoma, including the role of annexin A4, one of the most investigated factors of platinum resistance, as well as the mutant genes and overexpressed proteins such as VEGF, PI3K/AKT/mTOR signaling pathway, ARID1A, hepatocyte nuclear factor-1β, ZNF217. We also review targeted molecular therapeutics for epithelial ovarian cancer and discuss their role in clear cell carcinoma treatment. We review the drugs targeting angiogenesis (bevacizumab, sorafenib, and pazopanib), growth factors (gefitinib, erlotinib, lapatinib, trastuzumab, and AMG479), and signaling pathways (temsirolimus, dasatinib, and imatinib), and other drugs (oregovomab, volociximab, and iniparib). This current review summarizes and discusses the clinical significance of these factors in ovarian clear cell carcinoma as well as their potential mechanisms of action. It may provide new integrative understanding for future studies on their exact role in ovarian clear cell carcinoma.

HNF1β drives glutathione (GSH) synthesis underlying intrinsic carboplatin resistance of ovarian clear cell carcinoma (OCCC)

Chemoresistance to platinum-based antineoplastic agents is a consistent feature among ovarian carcinomas; however, whereas high-grade serous carcinoma (OSC) acquires resistance during chemotherapy, ovarian clear cell carcinoma (OCCC) is intrinsically resistant. The main objective of this study was to explore, in vitro and in vivo, if hepatocyte nuclear factor 1β (HNF1β) and glutaminolysis contribute for the resistance of OCCC to carboplatin through the intrinsically increased GSH bioavailability. To disclose the role of HNF1β, experiments were also performed in an OSC cell line, which does not express HNF1β. Metabolic profiles, GSH quantification, HNF1β, and γ-glutamylcysteine ligase catalytic subunit (GCLC) and modifier subunit (GCLM) expression, cell cycle, and death were assessed in ES2 cell line (OCCC) and OVCAR3 cell line (OSC); HNF1β knockdown was performed in ES2 and murine model of subcutaneous and peritoneal OCCC tumors was established to test buthionine sulphoxamine (BSO), as a sensitizer to carboplatin. Glutaminolysis is activated in ES2 and OVCAR3, though ES2 exclusively synthesizes amino acids and GSH. ES2 cells are more resistant to carboplatin than OVCAR3 and the abrogation of GSH production by BSO sensitizes ES2 to carboplatin. HNF1β regulates the expression of GCLC, but not GCLM, and consequently GSH production in ES2. In vivo, BSO prior to carboplatin reduces dramatically subcutaneous tumor size and GSH levels, as well as peritoneal dissemination. Our study discloses HNF1β as the mediator of intrinsic OCCC chemoresistance and sheds a light to re-explore a cancer adjuvant therapeutic approach using BSO to overcome the lack of efficient therapy in OCCC.

Evidence for the Relationship Between Endometriosis and Epithelial Ovarian Cancer

Endometriosis may be a precursor lesion for some epithelial ovarian cancers (EOCs), especially those of clear cell and endometrioid histologies. The causality of this relationship remains controversial and in need of further investigation because the high prevalence of endometriosis and high mortality of EOC carry significant public health implications if the association is real. Endometriosis-associated ovarian cancer (EAOC) often presents at an earlier stage and with lower-grade lesions than non-EAOC. After surgical resection, these patients also tend to have less residual disease than do patients with non-EAOC. Survival has been reported to be better for women with EAOC. The tumor suppression gene, ARID1A, is frequently disrupted in EAOC. The ARID1A mutation has been reported in preneoplastic lesions and may be an early marker in the transformation of endometriosis into cancer. The current evidence in respect to critical molecular pathways underscores the need to investigate possible role of targeted therapies in the treatment of EAOC.

Ovarian clear cell carcinoma with plasma cell-rich inflammatory stroma: a clear cell carcinoma subgroup with distinct clinicopathological features

AIMS

Ovarian clear cell carcinoma has a unique stroma. Although a hyalinized or mucoid stroma is more common, the stroma sometimes shows a dense inflammatory infiltrate, simulating a dysgerminoma. The aim of this study was to analyse the character and significance of the inflammatory stroma.

METHODS AND RESULTS

Twelve of 60 (20%) clear cell carcinomas showed an inflammatory stroma. The inflammatory stroma and hyalinized/mucoid stroma were mutually exclusive. Inflammatory cells were predominantly composed of CD138-positive plasma cells. As compared with the non-inflammatory cases, the epithelial component frequently showed a solid growth pattern and immunoreactivity for cyclooxygenase-2, one of the critical proinflammatory enzymes (P < 0.005). These findings were repeated after heterotransplantation of three clear cell carcinoma cell lines into athymic nude mice. In particular, xenografts of one cell line (JHOC-5) were infiltrated by mature plasma cells, indicating that plasma cell differentiation was stimulated by JHOC-5 cells, independently of T lymphocytes. Clinicopathologically, the frequency of International Federation of Gynaecology and Obstetrics stage III was higher in the cases with an inflammatory stroma than in those without it (P < 0.01).

CONCLUSIONS

Clear cell carcinomas with an inflammatory stroma constitute a distinct clinicopathological subgroup. It is strongly suggested that tumour cells themselves are responsible for inducing inflammation and stimulating plasma cell differentiation in a paracrine manner.

Transcriptional upregulation of HNF-1β by NF-κB in ovarian clear cell carcinoma modulates susceptibility to apoptosis through alteration in bcl-2 expression

Hepatocyte nuclear factor-1β (HNF-1β) is a transcriptional factor that has an important role in endometriosis-ovarian clear cell carcinoma (OCCC) sequence by modulating cell kinetics and glucose metabolism. However, little is known about the detailed molecular mechanisms that govern its regulation and function. Herein, we focus on upstream and downstream regulatory factors of HNF-1β in OCCCs. In clinical samples, HNF-1β expression was positively correlated with the active form of NF-κB/p65 in OCCCs, and closely linked with a low nuclear grade and non-solid architecture. In cell lines, transfection of p65 resulted in increased HNF-1β mRNA and protein expression in TOV-21G cells (OCCC cell line with endogenous HNF-1β expression), in line with activation of the promoter, probably through interacting with the basic transcriptional machinery. Suppression of endogenous HNF-1β expression by siRNA increased apoptosis in TOV-21G cells, while treatment of Hec251 cells (endometrial carcinoma cell line with extremely low endogenous HNF-1β expression) stably overexpressing exogenous HNF-1β with doxorubicin abrogated apoptosis of the cells, along with increased ratio of bcl-2 relative to bax. Moreover, overexpression of HNF-1β led to upregulation of bcl-2 expression at the transcriptional level in TOV-21G cells, which provided evidence for a positive correlation between HNF-1β and bcl-2 expression in OCCCs. These data, therefore, suggest that association between HNF-1β and NF-κB signaling may participate in cell survival by alteration of apoptotic events, particularly in mitochondria-mediated pathways, through upregulation of bcl-2 expression in OCCCs.

Venous thromboembolism, interleukin-6 and survival outcomes in patients with advanced ovarian clear cell carcinoma

BACKGROUND

We compared survival outcomes and risk of venous thromboembolism (VTE) among patients with advanced and early-stage ovarian clear cell carcinoma (OCCC) and serous ovarian carcinoma (SOC), as well as potential links with interleukin-6 (IL-6) levels.

METHODS

A multicenter case-control study was conducted in 370 patients with OCCC and 938 with SOC. In a subset of 200 cases, pretreatment plasma IL-6 levels were examined.

FINDINGS

Patients with advanced OCCC had the highest 2-year cumulative VTE rates (advanced OCCC 43.1%, advanced SOC 16.2%, early-stage OCCC 11.9% and early-stage SOC 6.4%, P<0.0001) and the highest median levels of IL-6 (advanced OCCC 17.8 pg/mL, advanced SOC 9.0 pg/mL, early-stage OCCC 4.2 pg/mL and early-stage SOC 5.0 pg/mL, P=0.006). Advanced OCCC (hazard ratio [HR] 3.38, P<0.0001), thrombocytosis (HR 1.42, P=0.032) and elevated IL-6 (HR 8.90, P=0.046) were independent predictors of VTE. In multivariate analysis, patients with advanced OCCC had significantly poorer 5-year progression-free and overall survival rates than those with advanced SOC (P<0.01), and thrombocytosis was an independent predictor of decreased survival outcomes (P<0.01). Elevated IL-6 levels led to poorer 2-year progression-free survival rates in patients with OCCC (50% versus 87.5%, HR 4.89, P=0.016) than in those with SOC (24.9% versus 40.8%, HR 1.40, P=0.07).

INTERPRETATION

Advanced OCCC is associated with an increased incidence of VTE and decreased survival outcomes, which has major implications for clinical management of OCCC.

Comparison of pure and mixed-type clear cell carcinoma of the ovary: a clinicopathological analysis of 341 Chinese patients

OBJECTIVE

This study aimed to analyze the clinicopathological features of pure and mixed-type ovarian clear cell carcinoma (CCC) in Chinese patients.

METHODS

Patients with ovarian CCC treated in our institution between 1982 and 2012 were identified by reviewing the database and medical charts. Patients were assigned into 2 groups based on histology (pure or mixed). Comparison of clinicopathological parameters was performed to determine the similarities and/or differences between pure and mixed CCC. Kaplan-Meier model was used in survival analysis.

RESULTS

Of 341 patients with ovarian CCC, 46 (13.5%) mixed tumors were identified, and the most common combination was clear cell/endometrioid, accounting for 56.5%. Patients with mixed-type CCC tended to have higher level of serum cancer antigen 125 (P = 0.023) and advanced tumor stage (P = 0.001). No difference was observed in other features including age, tumor size, residual disease, lymph node metastasis, and coexisting endometriosis. Tumor recurrence occurred in 47.8% and 58.1% in patients with pure and mixed histology, respectively (P = 0.209). Two groups had comparable platinum-sensitive disease (42.1% in pure and 44.0% in mixed type, P = 0.860). Patients with pure CCC had an improved median survival (105 vs 56 months), although statistical significance was not achieved. Histology subclassification of mixed tumor revealed that patients with clear cell/endometrioid histology had better survival outcome than those with clear cell/serous type (median survival, 140 vs 43 months, P = 0.004; median progression-free survival, 49 vs 12 months, P = 0.001).

CONCLUSIONS

Patients with mixed CCC tended to have elevated serum cancer antigen 125 and advanced tumor stage. However, no significant difference was observed between the pure and mixed tumors regarding prognosis.

Pathobiology of ovarian carcinomas

Ovarian tumors comprise a heterogeneous group of lesions, displaying distinct tumor pathology and oncogenic potentiel. These tumors are subdivided into three main categories: epithelial, germ cell, and sex-cord stromal tumors. We report herein the newly described molecular abnormalities in epithelial ovarian cancers (carcinomas). Immunohistochemistry and molecular testing help pathologists to decipher the significant heterogeneity of this disease. Our better understanding of the molecular basis of ovarian carcinomas represents the first step in the development of targeted therapies in the near future.

Integrated copy number and expression analysis identifies profiles of whole-arm chromosomal alterations and subgroups with favorable outcome in ovarian clear cell carcinomas

Ovarian clear cell carcinoma (CCC) is generally associated with chemoresistance and poor clinical outcome, even with early diagnosis; whereas high-grade serous carcinomas (SCs) and endometrioid carcinomas (ECs) are commonly chemosensitive at advanced stages. Although an integrated genomic analysis of SC has been performed, conclusive views on copy number and expression profiles for CCC are still limited. In this study, we performed single nucleotide polymorphism analysis with 57 epithelial ovarian cancers (31 CCCs, 14 SCs, and 12 ECs) and microarray expression analysis with 55 cancers (25 CCCs, 16 SCs, and 14 ECs). We then evaluated PIK3CA mutations and ARID1A expression in CCCs. SNP array analysis classified 13% of CCCs into a cluster with high frequency and focal range of copy number alterations (CNAs), significantly lower than for SCs (93%, P < 0.01) and ECs (50%, P = 0.017). The ratio of whole-arm to all CNAs was higher in CCCs (46.9%) than SCs (21.7%; P < 0.0001). SCs with loss of heterozygosity (LOH) of BRCA1 (85%) also had LOH of NF1 and TP53, and LOH of BRCA2 (62%) coexisted with LOH of RB1 and TP53. Microarray analysis classified CCCs into three clusters. One cluster (CCC-2, n = 10) showed more favorable prognosis than the CCC-1 and CCC-3 clusters (P = 0.041). Coexistent alterations of PIK3CA and ARID1A were more common in CCC-1 and CCC-3 (7/11, 64%) than in CCC-2 (0/10, 0%; P < 0.01). Being in cluster CCC-2 was an independent favorable prognostic factor in CCC. In conclusion, CCC was characterized by a high ratio of whole-arm CNAs; whereas CNAs in SC were mainly focal, but preferentially caused LOH of well-known tumor suppressor genes. As such, expression profiles might be useful for sub-classification of CCC, and might provide useful information on prognosis.

Categorization of cancer through genomic complexity could guide research and management strategies

Cancer management decisions are currently informed by cancer type and clinical stage, as well as age, health condition, and individual patient needs. Cancer is a genetic disease and recent genomic studies have revealed the genomic landscape of multiple tumour types. This has led to readily available catalogues of genomic features for many cancers and efforts to incorporate such information into treatment decisions. From this has evolved the concept that mutation-based taxonomies may supersede the current cell of origin-based categorization of neoplasia. Unfortunately, genomic features as clinically actionable information may not be directly transferable between tumour types, due to the importance of cellular and genomic context. However, we believe that high-level views of different genomic landscapes could broadly inform research study design and treatment strategies. Herein, we use ovarian and bone cancer as examples to propose a genomic complexity-based categorization for cancer. In addition to informing clinical study design, we describe how this categorization scheme could impact (i) improvement of accuracy of histological diagnoses, (ii) stratification of patients for targeted therapies, (iii) research study design, and (iv) personalized treatment strategies.

The clinical characteristics and outcomes of cases with pure ovarian clear cell, mixed type and high-grade serous adenocarcinoma

PURPOSE

This study aimed to compare the clinical characteristics and outcomes of the cases with pure ovarian clear cell adenocarcinoma (OCCC), mixed type (clear plus serous or clear plus endometrioid or serous plus clear plus endometrioid) ovarian adenocarcinoma (MOC) and high-grade serous ovarian adenocarcinoma (HGSOC).

METHODS

A retrospective comparison was conducted in 32 cases with pure OCCC, 23 cases with MOC and 28 cases with HGSOC followed between January 1999 and October 2011. Clinico-pathologic characteristics including histopathologic subtypes, age, stage, presence of ascites and/or peritoneal carcinomatosis, endometriosis and optimal cytoreduction, and also survival rates were compared in these three groups.

RESULTS

The cases with pure OCCC were younger than the cases with MOC and HGSOC (p = 0.004). The median pre-operative CA-125 level was lower in the pure OCCC than in MOC and HGSOC (p = 0.006) (p = 0.001, p = <0.001, respectively). Bilaterality and peritoneal carcinomatosis were more frequently seen in the HGSOC group (p = 0.001, p < 0.001, respectively). The majority of the cases (65 %) had stage I or II disease in the pure OCCC group, but most of the cases in the HGSOC group had advanced stage disease (p < 0.001). Endometriosis was found in 16 cases (16/55, 29 %) in the OCCC group. No significant difference was detected with regard to the median survival rate among three groups (p = 0.517), while the stage of disease was found to be the only important factor for survival (p = 0.002).

CONCLUSION

Pure OCCC, MOC and HGSOC represent distinct clinical characteristics. Clinical characteristics of MOC are more similar to those of HGSOC.

Multifocal endometriotic lesions associated with cancer are clonal and carry a high mutation burden

Endometriosis is a significant risk factor for clear cell and endometrioid ovarian cancers and is often found contiguous with these cancers. Using whole‐genome shotgun sequencing of seven clear cell ovarian carcinomas (CCC) and targeted sequencing in synchronous endometriosis, we have investigated how this carcinoma may evolve from endometriosis. In every case we observed multiple tumour‐associated somatic mutations in at least one concurrent endometriotic lesion. ARID1A and PIK3CA mutations appeared consistently in concurrent endometriosis when present in the primary CCC. In several cases, one or more endometriotic lesions carried the near‐complete complement of somatic mutations present in the index CCC tumour. Ancestral mutations were detected in both tumour‐adjacent and ‐distant endometriotic lesions, regardless of any cytological atypia. These findings provide objective evidence that multifocal benign endometriotic lesions are clonally related and that CCCs arising in these patients progress from endometriotic lesions that may already carry sufficient cancer‐associated mutations to be considered neoplasms themselves, albeit with low malignant potential. We speculate that genomically distinct classes of endometriosis exist and that ovarian endometriosis with high mutational burden represents one class at high risk for malignant transformation. © 2015 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

DJ-1 in endometrial cancer: a possible biomarker to improve differential diagnosis between subtypes

OBJECTIVE

The objectives of this study were to characterize the well-defined endometrial cancer (EC) type I (endometrioid [EEC] G1-G2) versus the prototype of EC type II (serous [ESC]) and to evaluate the expression of specific biomarkers differentially expressed between 2 well-defined types, in those EC subtypes (such as EEC G3) disputed between types I and II.

METHODS

Data from 25 patients (10 EEC G1-G2, 8 EEC G3, 5 ESC, and 2 clear cell) submitted to the surgical treatment were collected. Two-dimensional electrophoresis and mass spectrometry (MS) analysis were performed on 5 EEC G1-G2 and 5 healthy endometrial samples of the same patients. Differentially expressed proteins, such as DJ-1, were validated by Western blot. In patients with EEC G1-G2, serum levels of DJ-1, an overexpressed oncoprotein related to EC pathogenesis and progression, were evaluated and then compared with levels identified in patients with ESC and healthy controls. The DJ-1 immunohistochemical (IHC) staining was performed on neoplastic and healthy endometrium collected from the same patients. The 8 stored samples of EEC G3 were submitted to DJ-1 IHC assays.

RESULTS

The 2-dimensional electrophoresis analysis identified 1040 protein spots differentially expressed in EEC G1-G2 compared with healthy endometrium. Forty-two spots were subjected to liquid chromatography-MS/MS analysis. Thirty-three up-regulated (like an annexin 2 [ANXA2] shorter isoform, CAPG [macrophage-capping protein], DJ-1/PARK7) and 9 down-regulated (like calreticulin and ubiquitin carboxyl-terminal hydrolase isozyme L1) proteins were identified and validated by Western blot. A significant increase in serum DJ-1 levels of EEC G1-G2 versus the healthy controls and in ESC versus EEC patients was observed. DJ-1 IHC score was significantly higher in ESC versus those EEC G1-G2. In 3 cases of EEC G3, the DJ-1 expression was similar to the ESC subtype.

CONCLUSIONS

The identification of proteins, such as DJ-1, differentially expressed, between well-defined EC types I and II allows to make a subtype-specific presurgical diagnosis and help surgeon to safely preoperatively choose a proper surgical treatment.

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

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

Evidence for a time-dependent association between FOLR1 expression and survival from ovarian carcinoma: implications for clinical testing. An Ovarian Tumour Tissue Analysis consortium study

BACKGROUND

Folate receptor 1 (FOLR1) is expressed in the majority of ovarian carcinomas (OvCa), making it an attractive target for therapy. However, clinical trials testing anti-FOLR1 therapies in OvCa show mixed results and require better understanding of the prognostic relevance of FOLR1 expression. We conducted a large study evaluating FOLR1 expression with survival in different histological types of OvCa.

METHODS

Tissue microarrays composed of tumour samples from 2801 patients in the Ovarian Tumour Tissue Analysis (OTTA) consortium were assessed for FOLR1 expression by centralised immunohistochemistry. We estimated associations for overall (OS) and progression-free (PFS) survival using adjusted Cox regression models. High-grade serous ovarian carcinomas (HGSC) from The Cancer Genome Atlas (TCGA) were evaluated independently for association between FOLR1 mRNA upregulation and survival.

RESULTS

FOLR1 expression ranged from 76% in HGSC to 11% in mucinous carcinomas in OTTA. For HGSC, the association between FOLR1 expression and OS changed significantly during the years following diagnosis in OTTA (Pinteraction=0.01, N=1422) and TCGA (Pinteraction=0.01, N=485). In OTTA, particularly for FIGO stage I/II tumours, patients with FOLR1-positive HGSC showed increased OS during the first 2 years only (hazard ratio=0.44, 95% confidence interval=0.20-0.96) and patients with FOLR1-positive clear cell carcinomas (CCC) showed decreased PFS independent of follow-up time (HR=1.89, 95% CI=1.10-3.25, N=259). In TCGA, FOLR1 mRNA upregulation in HGSC was also associated with increased OS during the first 2 years following diagnosis irrespective of tumour stage (HR: 0.48, 95% CI: 0.25-0.94).

CONCLUSIONS

FOLR1-positive HGSC tumours were associated with an increased OS in the first 2 years following diagnosis. Patients with FOLR1-negative, poor prognosis HGSC would be unlikely to benefit from anti-FOLR1 therapies. In contrast, a decreased PFS interval was observed for FOLR1-positive CCC. The clinical efficacy of FOLR1-targeted interventions should therefore be evaluated according to histology, stage and time following diagnosis.

Evidence for a time-dependent association between FOLR1 expression and survival from ovarian carcinoma: implications for clinical testing. An Ovarian Tumour Tissue Analysis consortium study

BACKGROUND

Folate receptor 1 (FOLR1) is expressed in the majority of ovarian carcinomas (OvCa), making it an attractive target for therapy. However, clinical trials testing anti-FOLR1 therapies in OvCa show mixed results and require better understanding of the prognostic relevance of FOLR1 expression. We conducted a large study evaluating FOLR1 expression with survival in different histological types of OvCa.

METHODS

Tissue microarrays composed of tumour samples from 2801 patients in the Ovarian Tumour Tissue Analysis (OTTA) consortium were assessed for FOLR1 expression by centralised immunohistochemistry. We estimated associations for overall (OS) and progression-free (PFS) survival using adjusted Cox regression models. High-grade serous ovarian carcinomas (HGSC) from The Cancer Genome Atlas (TCGA) were evaluated independently for association between FOLR1 mRNA upregulation and survival.

RESULTS

FOLR1 expression ranged from 76% in HGSC to 11% in mucinous carcinomas in OTTA. For HGSC, the association between FOLR1 expression and OS changed significantly during the years following diagnosis in OTTA (Pinteraction=0.01, N=1422) and TCGA (Pinteraction=0.01, N=485). In OTTA, particularly for FIGO stage I/II tumours, patients with FOLR1-positive HGSC showed increased OS during the first 2 years only (hazard ratio=0.44, 95% confidence interval=0.20-0.96) and patients with FOLR1-positive clear cell carcinomas (CCC) showed decreased PFS independent of follow-up time (HR=1.89, 95% CI=1.10-3.25, N=259). In TCGA, FOLR1 mRNA upregulation in HGSC was also associated with increased OS during the first 2 years following diagnosis irrespective of tumour stage (HR: 0.48, 95% CI: 0.25-0.94).

CONCLUSIONS

FOLR1-positive HGSC tumours were associated with an increased OS in the first 2 years following diagnosis. Patients with FOLR1-negative, poor prognosis HGSC would be unlikely to benefit from anti-FOLR1 therapies. In contrast, a decreased PFS interval was observed for FOLR1-positive CCC. The clinical efficacy of FOLR1-targeted interventions should therefore be evaluated according to histology, stage and time following diagnosis.

Harnessing the potential of lipid-based nanomedicines for type-specific ovarian cancer treatments

Epithelial ovarian cancers are a group of at least five histologically and clinically distinct diseases, yet at this time patients with these different diseases are all treated with the same platinum and taxane-based chemotherapeutic regimen. With increased knowledge of histotype-specific differences that correlate with treatment responses and resistance, novel treatment strategies will be developed for each distinct disease. Type-specific or resistance-driven molecularly targeted agents will provide some specificity over traditional chemotherapies and it is argued here that nanoscaled drug delivery systems, in particular lipid-based formulations, have the potential to improve the delivery and specificity of pathway-specific drugs and broad-spectrum cytotoxic chemotherapeutics. An overview of the current understanding of ovarian cancers and the evolving clinical management of these diseases is provided. This overview is needed as it provides the context for understanding the current role of drug delivery systems in the treatment of ovarian cancer and the need to design formulations for treatment of clinically distinct forms of ovarian cancer.

Gynecologic Cancer InterGroup (GCIG) consensus review for clear cell carcinoma of the ovary

Clear cell carcinoma of the ovary (CCC) is a histologic subtype of epithelial ovarian cancer with a distinct clinical behavior. There are marked geographic differences in the prevalence of CCC. The CCC is more likely to be detected at an early stage than high-grade serous cancers, and when confined within the ovary, the prognosis is good. However, advanced disease is associated with a very poor prognosis and resistance to standard treatment. Cytoreductive surgery should be performed for patients with stage II, III, or IV disease. An international phase III study to compare irinotecan/cisplatin and paclitaxel/carboplatin as adjuvant chemotherapy for stage IIV CCC has completed enrollment (GCIG/JGOG3017). Considering the frequent PIK3CA mutation in CCC, dual inhibitors targeting PI3K, AKT in the mTOR pathway, are promising. Performing these trials and generating the evidence will require considerable international collaboration.

Expression of mitochondrial regulators PGC1α and TFAM as putative markers of subtype and chemoresistance in epithelial ovarian carcinoma

Epithelial ovarian carcinoma (EOC), the major cause of gynaecological cancer death, is a heterogeneous disease classified into five subtypes. Each subtype has distinct clinical characteristics and is associated with different genetic risk factors and molecular events, but all are treated with surgery and platinum/taxane regimes. Tumour progression and chemoresistance is generally associated with major metabolic alterations, notably altered mitochondrial function(s). Here, we report for the first time that the expression of the mitochondrial regulators PGC1α and TFAM varies between EOC subtypes; furthermore, we have identified a profile in clear-cell carcinoma consisting of undetectability of PGC1α/TFAM, and low ERα/Ki-67. By contrast, high-grade serous carcinomas were characterised by a converse state of PGC1α/TFAM, ERα positivity and a high Ki-67 index. Interestingly, loss of PGC1α/TFAM and ERα was found also in a non-clear cell EOC cell line made highly resistant to platinum in vitro. Similar to clear-cell carcinomas, these resistant cells also showed accumulation of glycogen. Altogether, our data provide mechanistic insights into the chemoresistant nature of ovarian clear-cell carcinomas. Furthermore, these findings corroborate the need to take into account the diversity of EOC and to develop subtype specific treatment strategies.