Patterns of gene expression in different histotypes of epithelial ovarian cancer correlate with those in normal fallopian tube, endometrium, and colon

Peritoneal carcinomatosis: A malignant disease with an embryological origin?

INTRODUCTION

In 1931, Simpson et al. coined the term "peritoneal carcinomatosis" to describe the regional spread of ovarian tumors as localized or extended with involvement of the peritoneal serous membrane and neighboring anatomical structures. Research into the origin of peritoneal carcinomatosis is based on two phases in a woman's life: EMBRYO DEVELOPMENT: During week 3, the bilaminar disc becomes a trilaminar disc called the mesoderm. Inside the lateral plate mesoderm, the coelomic cavity is divided into 2 layers: the parietal (somatic) mesoderm, which gives rise to the parietal peritoneum and pleural surfaces; and the visceral (splanchnic) mesoderm, which gives rise to the visceral peritoneum, visceral surface of the pleura, gonadal stroma, and the muscular layer of the hollow viscera and its mesenteries.

TUMOR SPREAD

Transcoelomic metastasis and metaplasia of pluripotent stem cells in the peritoneum was involved in the pathogenesis of ovarian cancer. This involvement takes the form of a synchronous malignant transformation at multiple foci and may cause intraperitoneal field cancerization. Pluripotent stem cells play a role both in the development of the embryonic peritoneum and in the spread of transcoelomic tumors. Consequently, knowledge of the origin of these cells (embryonic or current) could be extremely useful. The many markers that act during the embryonic period can affect descendants, that is, cells are already marked before specification and differentiation are activated. Thus, programmed activation could be attributed to genetic and epigenetic changes.

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.

Systematic transcriptome analysis reveals tumor-specific isoforms for ovarian cancer diagnosis and therapy

Tumor-specific molecules are needed across diverse areas of oncology for use in early detection, diagnosis, prognosis and therapy. Large and growing public databases of transcriptome sequencing data (RNA-seq) derived from tumors and normal tissues hold the potential of yielding tumor-specific molecules, but because the data are new they have not been fully explored for this purpose. We have developed custom bioinformatic algorithms and used them with 296 high-grade serous ovarian (HGS-OvCa) tumor and 1,839 normal RNA-seq datasets to identify mRNA isoforms with tumor-specific expression. We rank prioritized isoforms by likelihood of being expressed in HGS-OvCa tumors and not in normal tissues and analyzed 671 top-ranked isoforms by high-throughput RT-qPCR. Six of these isoforms were expressed in a majority of the 12 tumors examined but not in 18 normal tissues. An additional 11 were expressed in most tumors and only one normal tissue, which in most cases was fallopian or colon. Of the 671 isoforms, the topmost 5% (n = 33) ranked based on having tumor-specific or highly restricted normal tissue expression by RT-qPCR analysis are enriched for oncogenic, stem cell/cancer stem cell, and early development loci--including ETV4, FOXM1, LSR, CD9, RAB11FIP4, and FGFRL1. Many of the 33 isoforms are predicted to encode proteins with unique amino acid sequences, which would allow them to be specifically targeted for one or more therapeutic strategies--including monoclonal antibodies and T-cell-based vaccines. The systematic process described herein is readily and rapidly applicable to the more than 30 additional tumor types for which sufficient amounts of RNA-seq already exist.

Hereditary ovarian cancer: not only BRCA 1 and 2 genes

More than one-fifth of ovarian tumors have hereditary susceptibility and, in about 65-85% of these cases, the genetic abnormality is a germline mutation in BRCA genes. Nevertheless, several other suppressor genes and oncogenes have been associated with hereditary ovarian cancers, including the mismatch repair (MMR) genes in Lynch syndrome, the tumor suppressor gene, TP53, in the Li-Fraumeni syndrome, and several other genes involved in the double-strand breaks repair system, such as CHEK2, RAD51, BRIP1, and PALB2. The study of genetic discriminators and deregulated pathways involved in hereditary ovarian syndromes is relevant for the future development of molecular diagnostic strategies and targeted therapeutic approaches. The recent development and implementation of next-generation sequencing technologies have provided the opportunity to simultaneously analyze multiple cancer susceptibility genes, reduce the delay and costs, and optimize the molecular diagnosis of hereditary tumors. Particularly, the identification of mutations in ovarian cancer susceptibility genes in healthy women may result in a more personalized cancer risk management with tailored clinical and radiological surveillance, chemopreventive approaches, and/or prophylactic surgeries. On the other hand, for ovarian cancer patients, the identification of mutations may provide potential targets for biologic agents and guide treatment decision-making.

Progesterone-mediated effects on gene expression and oocyte-cumulus complex transport in the mouse fallopian tube

BACKGROUND

The fallopian tube transports the gametes to the fertilization site and delivers the embryo to the uterus at the optimal time for implantation. Progesterone and the classical progesterone receptor are involved in regulating both tubal ciliary beating and muscular contractions, likely via both genomic and non-genomic actions.

METHODS

To provide more details of the underlying mechanisms, we investigated the effect of progesterone on gene expression in mice fallopian tubes in vitro at 20 min, 2 h and 8 h post progesterone treatment using microarray and/or quantitative PCR. In parallel, oocyte cumulus complex transport was investigated in ovulating mice that were injected with one of the progesterone receptor antagonists, Org 31710 or CDB2194.

RESULTS

Microarray analyses did not reveal any apparently regulated genes 20 min after progesterone treatment, consistent with the proposed non-genomic action of progesterone controlling ciliary beating. After 2 h, 11 genes were identified as up-regulated. Analyses using quantitative PCR at 2 h and 8 h showed a consistent up-regulation of endothelin1 and a down-regulation of its receptor Endothelin receptor A by progesterone. We also confirmed that treatment with progesterone receptor antagonists before ovulation accelerates the transport of the oocyte cumulus complex.

CONCLUSIONS

This is the first study showing that progesterone regulates the expression of endothelin1 and endothelin receptor A in the fallopian tube. Together with previous studies of the effects of endothelin on muscular contractions in the fallopian tube, the results from this study suggest that endothelin is a mediator of the progesterone-controlled effects on muscular contraction and eventually gamete transport in the fallopian tube.

Incidental serous tubal intraepithelial carcinoma and early invasive serous carcinoma in the nonprophylactic setting: analysis of a case series

A precursor for invasive ovarian/pelvic high-grade serous carcinoma, termed serous tubal intraepithelial carcinoma (STIC), has been identified and characterized through careful analysis of the fallopian tubes in both prophylactic salpingo-oophorectomy specimens obtained from women with either a family history of breast and/or ovarian cancer or germline mutations of BRCA1 and BRCA2 and in cases of pelvic high-grade serous carcinoma. Data on incidental STICs and clinically occult microscopic invasive high-grade serous carcinomas are limited. We analyzed the clinicopathologic features of 22 cases, including 15 pure STICs and 7 STICs associated with microscopic invasive high-grade serous carcinomas, identified incidentally in fallopian tubes removed for nonprophylactic indications. Patient age ranged from 39 to 79 years (mean: 62.7; median: 61), with only 1 patient under the age of 50. No patients were known to carry BRCA1 or BRCA2 mutations. Of the 12 pure STICs for which the location in the fallopian tube could be established, 9 were in the fimbriated portion, 1 was at the junction of the fimbria and infundibulum, and 2 were in the nonfimbriated tube. Of the 7 STICs with associated invasive high-grade serous carcinoma, 3 were located in the fimbriated portion, 2 were at the junction of the fimbria and infundibulum, and 2 were in the nonfimbriated tube. The invasive components were in the fallopian tube in 6 cases, 4 in subepithelial stroma of tubal mucosa, and 2 as an intramucosal (exophytic) luminal lesion without invasion of underlying subepithelial stroma (size range: 1 to 4 mm). The remaining case had a microscopic focus of high-grade serous carcinoma within the ipsilateral ovary (1.3 mm cortical focus) identified only on deeper sections, without an associated invasive component in the fallopian tube. The preferential finding of atypical epithelium with the cytologic features of high-grade serous carcinoma, namely STIC, in the fallopian tubes rather than the ovaries as an incidental (clinically occult) microscopic lesion in the absence of widespread pelvic carcinoma provides further evidence that STIC is the earliest form of pelvic high-grade serous carcinoma and that the fallopian tube is the site of origin. This study demonstrates the potential for complete examination of the fallopian tubes and ovaries to identify STICs and early invasive serous carcinomas that might be more amenable to the earliest intervention and potential cure.

Society of Gynecologic Oncology recommendations for the prevention of ovarian cancer

Mortality from ovarian cancer may be dramatically reduced with the implementation of attainable prevention strategies. The new understanding of the cells of origin and the molecular etiology of ovarian cancer warrants a strong recommendation to the public and health care providers. This document discusses potential prevention strategies, which include 1) oral contraceptive use, 2) tubal sterilization, 3) risk-reducing salpingo-oophorectomy in women at high hereditary risk of breast and ovarian cancer, 4) genetic counseling and testing for women with ovarian cancer and other high-risk families, and 5) salpingectomy after childbearing is complete (at the time of elective pelvic surgeries, at the time of hysterectomy, and as an alternative to tubal ligation). The Society of Gynecologic Oncology has determined that recent scientific breakthroughs warrant a new summary of the progress toward the prevention of ovarian cancer. This review is intended to emphasize the importance of the fallopian tubes as a potential source of high-grade serous cancer in women with and without known genetic mutations in addition to the use of oral contraceptive pills to reduce the risk of ovarian cancer.

Updates and emerging therapies for rare epithelial ovarian cancers: one size no longer fits all

Epithelial ovarian carcinoma consists of not one, but several, entities. A number of subtypes exist, including high-grade and low-grade serous carcinomas, clear cell, endometrioid carcinoma and mucinous carcinoma. Historically, women with epithelial ovarian cancer have been treated similarly and "lumped" in the same cooperative group treatment trials, irrespective of their tumor subtype. Recently, however, differences in epidemiology, tumor biology, tumor marker expression and treatment responses have been elucidated among the histologic subtypes, with a clear distinction emerging between the Type I, lower grade tumors and Type 2, higher grade epithelial malignancies. A mounting body of research demonstrates that a "one-size-fits-all" treatment approach to epithelial ovarian tumors is no longer relevant, especially for the Type I subtypes. Indeed, with the exception of high-grade serous carcinoma, most other epithelial subtypes exhibit some degree of chemotherapy resistance, rendering treatment problematic, especially in the setting of advanced disease. This review summarizes the genetic, molecular, and clinical differences of the more rare, but clinically important, Type I epithelial ovarian tumors. Additionally, a critical appraisal of both historical and contemporary treatment approaches and the rationale for targeted therapies are emphasized.

Role of microRNAs in cancers of the female reproductive tract: insights from recent clinical and experimental discovery studies

microRNAs (miRNAs) are small RNA molecules that represent the top of the pyramid of many tumorigenesis cascade pathways as they have the ability to affect multiple, intricate, and still undiscovered downstream targets. Understanding how miRNA molecules serve as master regulators in these important networks involved in cancer initiation and progression open up significant innovative areas for therapy and diagnosis that have been sadly lacking for deadly female reproductive tract cancers. This review will highlight the recent advances in the field of miRNAs in epithelial ovarian cancer, endometrioid endometrial cancer and squamous-cell cervical carcinoma focusing on studies associated with actual clinical information in humans. Importantly, recent miRNA profiling studies have included well-characterized clinical specimens of female reproductive tract cancers, allowing for studies correlating miRNA expression with clinical outcomes. This review will summarize the current thoughts on the role of miRNA processing in unique miRNA species present in these cancers. In addition, this review will focus on current data regarding miRNA molecules as unique biomarkers associated with clinically significant outcomes such as overall survival and chemotherapy resistance. We will also discuss why specific miRNA molecules are not recapitulated across multiple studies of the same cancer type. Although the mechanistic contributions of miRNA molecules to these clinical phenomena have been confirmed using in vitro and pre-clinical mouse model systems, these studies are truly only the beginning of our understanding of the roles miRNAs play in cancers of the female reproductive tract. This review will also highlight useful areas for future research regarding miRNAs as therapeutic targets in cancers of the female reproductive tract.

The PAX2-null immunophenotype defines multiple lineages with common expression signatures in benign and neoplastic oviductal epithelium

The oviducts contain high-grade serous cancer (HGSC) precursors (serous tubal intraepithelial neoplasia or STINs), which are γ-H2AX(p) - and TP53 mutation-positive. Although they express wild-type p53, secretory cell outgrowths (SCOUTs) are associated with older age and serous cancer; moreover, both STINs and SCOUTs share a loss of PAX2 expression (PAX2(n) ). We evaluated PAX2 expression in proliferating adult and embryonic oviductal cells, normal mucosa, SCOUTs, Walthard cell nests (WCNs), STINs, and HGSCs, and the expression of genes chosen empirically or from SCOUT expression arrays. Clones generated in vitro from embryonic gynaecological tract and adult Fallopian tube were Krt7(p) /PAX2(n) /EZH2(p) and underwent ciliated (PAX2(n) /EZH2(n) /FOXJ1(p) ) and basal (Krt7(n) /EZH2(n) /Krt5(p) ) differentiation. Similarly, non-ciliated cells in normal mucosa were PAX2(p) but became PAX2(n) in multi-layered epithelium undergoing ciliated or basal (WCN) cell differentiation. PAX2(n) SCOUTs fell into two groups: type 1 were secretory or secretory/ciliated with a 'tubal' phenotype and were ALDH1(n) and β-catenin(mem) (membraneous only). Type 2 displayed a columnar to pseudostratified (endometrioid) phenotype, with an EZH2(p) , ALDH1(p) , β-catenin(nc) (nuclear and cytoplasmic), stathmin(p) , LEF1(p) , RCN1(p) , and RUNX2(p) expression signature. STINs and HGSCs shared the type 1 immunophenotype of PAX2(n) , ALDH1(n) , β-catenin(mem) , but highly expressed EZH2(p) , LEF1(p) , RCN1(p) , and stathmin(p) . This study, for the first time, links PAX2(n) with proliferating fetal and adult oviductal cells undergoing basal and ciliated differentiation and shows that this expression state is maintained in SCOUTs, STINs, and HGSCs. All three entities can demonstrate a consistent perturbation of genes involved in potential tumour suppressor gene silencing (EZH2), transcriptional regulation (LEF1), regulation of differentiation (RUNX2), calcium binding (RCN1), and oncogenesis (stathmin). This shared expression signature between benign and neoplastic entities links normal progenitor cell expansion to abnormal and neoplastic outgrowth in the oviduct and exposes a common pathway that could be a target for early prevention.

Molecular subtyping of serous ovarian tumors reveals multiple connections to intrinsic breast cancer subtypes

OBJECTIVE

Transcriptional profiling of epithelial ovarian cancer has revealed molecular subtypes correlating to biological and clinical features. We aimed to determine gene expression differences between malignant, benign and borderline serous ovarian tumors, and investigate similarities with the well-established intrinsic molecular subtypes of breast cancer.

METHODS

Global gene expression profiling using Illumina's HT12 Bead Arrays was applied to 59 fresh-frozen serous ovarian malignant, benign and borderline tumors. Nearest centroid classification was performed applying previously published gene profiles for the ovarian and breast cancer subtypes. Correlations to gene expression modules representing key biological breast cancer features were also sought. Validation was performed using an independent, publicly available dataset.

RESULTS

5,944 genes were significantly differentially expressed between benign and malignant serous ovarian tumors, with cell cycle processes enriched in the malignant subgroup. Borderline tumors were split between the two clusters. Significant correlations between the malignant serous tumors and the highly aggressive ovarian cancer signatures, and the basal-like breast cancer subtype were found. The benign and borderline serous tumors together were significantly correlated to the normal-like breast cancer subtype and the ovarian cancer signature derived from borderline tumors. The borderline tumors in the study dataset, in addition, also correlated significantly to the luminal A breast cancer subtype. These findings remained when analyzed in an independent dataset, supporting links between the molecular subtypes of ovarian cancer and breast cancer beyond those recently acknowledged.

CONCLUSIONS

These data link the transcriptional profiles of serous ovarian cancer to the intrinsic molecular subtypes of breast cancer, in line with the shared clinical and molecular features between high-grade serous ovarian cancer and basal-like breast cancer, and suggest that biomarkers and targeted therapies may overlap between these tumor subsets. The link between benign and borderline ovarian cancer and luminal breast cancer may indicate endocrine responsiveness in a subset of ovarian cancers.

Demographic clinical and prognostic characteristics of primary ovarian, peritoneal and tubal adenocarcinomas of serous histology--a prospective comparative study

OBJECTIVES

Invasive serous adenocarcinomas may present as primary ovarian (POC), primary fallopian tube (PFC) or primary peritoneal (PPC) carcinomas. Whether they are variants of the same malignancy or develop through different pathways is debated.

METHODS

Population-based prospectively collected data on POC (n=1443), PPC (n=268) and PFC (n=171) cases was obtained from the Danish Gynecological Cancer Database (2005-2013). Chi-square, Fisher's or Wilcoxon-Mann-Whitney test, multivariate logistic regression, Kaplan-Meier and multivariate Cox-regression were used as appropriate. Statistical tests were 2-sided. P-values of <0.05 were considered statistically significant.

RESULTS

PPC cases were older (P<0.0001), had a later age at menarche (P=0.02), a higher percentage were multi-parous (≥two children vs. no children) OR 1.70 (1.01-2.49) and both PPC and PFC tended to have a higher BMI (>35 vs. >18.5-25) than POC cases. PFC cases were diagnosed in earlier stages (P<0.001). In advanced stages a lower proportion had preoperative carcinosis or ascites, and a higher percentage had macro-radical surgery or lymphadenectomy compared to POC. In contrast, more PPC cases had post-operative carcinosis; whereas a lower proportion had lymphadenectomy or macro-radical surgery compared to POC. PPC had a significantly lower overall survival than POC, HR=1.24 (1.04-1.47).

CONCLUSION

We found differences in risk pattern profiles among the three groups, especially for PPC. Furthermore, the severity of stage specific disease differed significantly according to location, resulting in a lower overall survival for PPC. These differences warrant further research to determine to what extent PPC is a distinct disease entity.

Ovulation and extra-ovarian origin of ovarian cancer

The mortality rate of ovarian cancer remains high due to late diagnosis and recurrence. A fundamental step toward improving detection and treatment of this lethal disease is to understand its origin. A growing number of studies have revealed that ovarian cancer can develop from multiple extra-ovarian origins, including fallopian tube, gastrointestinal tract, cervix and endometriosis. However, the mechanism leading to their ovarian localization is not understood. We utilized in vitro, ex vivo, and in vivo models to recapitulate the process of extra-ovarian malignant cells migrating to the ovaries and forming tumors. We provided experimental evidence to support that ovulation, by disrupting the ovarian surface epithelium and releasing chemokines/cytokines, promotes the migration and adhesion of malignant cells to the ovary. We identified the granulosa cell-secreted SDF-1 as a main chemoattractant that recruits malignant cells towards the ovary. Our findings revealed a potential molecular mechanism of how the extra-ovarian cells can be attracted by the ovary, migrate to and form tumors in the ovary. Our data also supports the association between increased ovulation and the risk of ovarian cancer. Understanding this association will lead us to the development of more specific markers for early detection and better prevention strategies.

Epigenetic determinants of ovarian clear cell carcinoma biology

Targeted approaches have revealed frequent epigenetic alterations in ovarian cancer, but the scope and relation of these changes to histologic subtype of disease is unclear. Genome-wide methylation and expression data for 14 clear cell carcinoma (CCC), 32 non-CCC and four corresponding normal cell lines were generated to determine how methylation profiles differ between cells of different histological derivations of ovarian cancer. Consensus clustering showed that CCC is epigenetically distinct. Inverse relationships between expression and methylation in CCC were identified, suggesting functional regulation by methylation, and included 22 hypomethylated (UM) genes and 276 hypermethylated (HM) genes. Categorical and pathway analyses indicated that the CCC-specific UM genes were involved in response to stress and many contain hepatocyte nuclear factor (HNF) 1-binding sites, while the CCC-specific HM genes included members of the estrogen receptor alpha (ERalpha) network and genes involved in tumor development. We independently validated the methylation status of 17 of these pathway-specific genes, and confirmed increased expression of HNF1 network genes and repression of ERalpha pathway genes in CCC cell lines and primary cancer tissues relative to non-CCC specimens. Treatment of three CCC cell lines with the demethylating agent Decitabine significantly induced expression for all five genes analyzed. Coordinate changes in pathway expression were confirmed using two primary ovarian cancer datasets (p < 0.0001 for both). Our results suggest that methylation regulates specific pathways and biological functions in CCC, with hypomethylation influencing the characteristic biology of the disease while hypermethylation contributes to the carcinogenic process.

Müllerian precursor lesions in serous ovarian cancer patients: using the SEE-Fim and SEE-End protocol

Serous ovarian cancer is suggested to develop from epithelium embryologically derived from the Müllerian ducts. The aim of the current study is to thoroughly, analyze the epithelium derived from the Müllerian ducts (cervix, endometrium and fallopian tubes) in serous ovarian cancer patients. Sixty women diagnosed with serous ovarian carcinoma were included in this multicentre, observational study. Tissues were embedded completely for histological assessment, in accordance with the SEE-Fim and SEE-End protocol (Sectioning and Extensively Examining of the Fimbriated end; and-Endometrium), and prevalence of cervical, as well as endometrial and tubal pathology was analyzed. In 31 (52%) cases, a pathologic lesion was identified, and in 16 (27%) of these cases coexistence of pathologic lesions. In 1 case, severe dysplasia was found in the cervix, in 9 (15%) cases endometrial intraepithelial carcinoma, in 19 (32%) cases atypical hyperplasia, and in 23 (43%) cases serous tubal intraepithelial carcinoma. Serous tubal intraepithelial carcinoma was seen significantly more often concurrent with endometrial atypical hyperplasia or endometrial intraepithelial carcinoma than with benign endometrium (64 vs 28%; P=0.01). To conclude, histological assessment of epithelium derived from Müllerian ducts of serous ovarian cancer patients resulted in the identification of endometrial intraepithelial carcinoma, serous tubal intraepithelial carcinoma and/or endometrial atypical hyperplasia in more than half of cases. Coexistence of these pathologic lesions was common, and might represent an effect of field carcinogenesis or tumor implantation of migrating cells.

Repeated ovarian stimulation does not affect the expression level of proteins involved in cell cycle control in mouse ovaries and fallopian tubes

PURPOSE

To understand if repeated cycles (2-4 rounds) of gonadotropin stimulation could affect intracellular localization/content of proteins controlling cell cycle progression in mouse fallopian tubes (FT) and ovaries.

METHODS

FT and ovaries of estrous mice (control) and of stimulated mice were analyzed to detect Oct-3/4, Sox-2, p53, β-catenin, pAKT and cyclin D1 localization/content. Spindles and chromosome alignment were analyzed in ovulated oocytes.

RESULTS

After round 4, FT and ovaries of control and stimulated groups showed no differences in Oct-3/4, Sox-2 and β-catenin localization nor in Oct-3/4, Sox-2, p53, β-catenin and pAKT contents. Cyclin D1 level increased significantly in FT of treated mice. Oocytes number decreased meanwhile frequency of abnormal meiotic spindles increased with treatments.

CONCLUSIONS

Repetitive stimulations affected oocyte spindle morphology but did not induce changes in a set of proteins involved in cell cycle progression, usually altered in ovarian cancer. The significant increase of cyclin D1 in the FT requires further investigation.

Gene expression analysis in ovarian cancer - faults and hints from DNA microarray study

The introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients’ treatment; however, the results of such studies are poorly reproducible and critical analyses of these methods are rare. In this study, we examined global gene expression in 97 ovarian cancer samples. Also, validation of results by quantitative RT-PCR was performed on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients’ prognosis. We found that histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints [tumor response to chemotherapy, overall survival, disease-free survival (DFS)] brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found to be important for DFS in the independent group, whereas in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worthy of further testing. Our results confirm that histological tumor type may be a strong confounding factor and we conclude that gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Among the reasons of poor reproducibility of statistical results may be the fact that despite relatively large patients’ group, in some analyses one has to compare small and unequal classes of samples. In addition, arbitrarily performed division of samples into classes compared may not always reflect their true biological diversity. And finally, we think that clinical endpoints of the tumor probably depend on subtle changes in many and, possibly, alternative molecular pathways, and such changes may be difficult to demonstrate.

Refractory fallopian tube carcinoma - current perspectives in pathogenesis and management

Fallopian tube carcinoma (FTC) is considered a rare malignancy, but recent evidence shows that its incidence may have been underestimated. Risk-reducing salpingo-oophorectomy (RRSO) in breast cancer susceptibility gene (BRCA)-positive women has provided a unique opportunity to study the pathogenesis of FTC and ovarian carcinomas. Newer data now suggest that most high-grade serous cancers of the ovary originate in the fimbrial end of the fallopian tube. Due to the presumed rarity of FTC, most current and more recent ovarian cancer clinical trials have now included patients with FTC. The treatment guidelines recommend similar overall management and that the same chemotherapy regimens be used for epithelial ovarian cancers and FTC.

Role of the interleukin 6 receptor family in epithelial ovarian cancer and its clinical implications

Ovarian cancer is the most lethal gynecological malignancy, with few effective treatment options in most cases. Therefore, understanding the biology of ovarian cancer remains an important area of research in order to improve clinical outcomes. Cytokine receptor signaling through the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is an essential component of normal development and homeostasis. However, numerous studies have implicated perturbation of this pathway in a range of cancers. In particular, members of the IL-6R family acting via the downstream STAT3 transcription factor play an important role in a number of solid tumors - including ovarian cancer - by altering the expression of target genes that impact on key phenotypes. This has led to the development of specific inhibitors of this pathway which are being used in combination with standard chemotherapeutic agents. This review focuses on the role of IL-6R family members in the etiology of epithelial ovarian cancer, and the application of therapies specifically targeting IL-6R signaling in this disease setting.

Through the glass darkly: intraepithelial neoplasia, top-down differentiation, and the road to ovarian cancer

It is currently hoped that deaths from extra-uterine high-grade serous cancer (HGSC) will be reduced via opportunistic salpingectomy in healthy women. Accumulated data implicate the fimbria as a site of origin and descriptive molecular pathology and experimental evidence strongly support a serous carcinogenic sequence in the Fallopian tube. Both direct and indirect ('surrogate') precursors suggest that the benign tube undergoes important biological changes after menopause, acquiring abnormalities in gene expression that are often shared with malignancy, including PAX2, ALDH1, LEF1, RCN1, RUNX2, beta-catenin, EZH2, and others. However, the tube can be linked to only some HGSCs, recharging arguments that nearby peritoneum/ovarian surface epithelium (POSE) also hosts progenitors to this malignancy. A major sticking point is the difference in immunophenotype between POSE and Müllerian epithelium, essentially requiring mesothelial to Müllerian differentiation prior to or during malignant transformation to HGSC. However, emerging evidence implicates an embryonic or progenitor phenotype in the adult female genital tract with the capacity to differentiate, normally or during neoplastic transformation. Recently, a putative cell of origin for cervical cancer has been identified in the squamo-columnar (SC) junction, projecting a model whereby Krt7+ embryonic progenitors give rise to immunophenotypically distinct progeny under stromal influences via 'top down' differentiation. Similar differentiation can be seen in the endometrium with a parallel in juxtaposed mesothelial and Müllerian differentiation in the ovary. Abrupt mesothelial-Müllerian transitions remain to be proven, but would explain the rapid evolution, short asymptomatic interval, and absence of a defined epithelial starting point in many HGSCs. Resolving this question will require accurately distinguishing progenitor from progeny tumour cells in HGSC and pinpointing where initial transformation and trans-differentiation occur, whether in the tube or POSE. Both will be critical to expectations from prophylactic salpingectomy and future approaches to pelvic serous cancer prevention.

Ovarian cancer biomarker discovery based on genomic approaches

Ovarian cancer presents at an advanced stage in more than 75% of patients. Early detection has great promise to improve clinical outcomes. Although the advancing proteomic technologies led to the discovery of numerous ovarian cancer biomarkers, no screening method has been recommended for early detection of ovarian cancer. Complexity and heterogeneity of ovarian carcinogenesis is a major obstacle to discover biomarkers. As cancer arises due to accumulation of genetic change, understanding the close connection between genetic changes and ovarian carcinogenesis would provide the opportunity to find novel gene-level ovarian cancer biomarkers. In this review, we summarize the various gene-based biomarkers by genomic technologies, including inherited gene mutations, epigenetic changes, and differential gene expression. In addition, we suggest the strategy to discover novel gene-based biomarkers with recently introduced next generation sequencing.

Gynecologic cancers: molecular updates

This article reviews the molecular features and pathogenesis of gynecologic malignancies. Understanding the molecular basis of endometrial carcinoma helps to provide an explanation for the prognosis of these tumors and opens up avenues for research into novel therapies that may prove beneficial.

Gene expression signature of normal cell-of-origin predicts ovarian tumor outcomes

The potential role of the cell-of-origin in determining the tumor phenotype has been raised, but not adequately examined. We hypothesized that distinct cells-of-origin may play a role in determining ovarian tumor phenotype and outcome. Here we describe a new cell culture medium for in vitro culture of paired normal human ovarian (OV) and fallopian tube (FT) epithelial cells from donors without cancer. While these cells have been cultured individually for short periods of time, to our knowledge this is the first long-term culture of both cell types from the same donors. Through analysis of the gene expression profiles of the cultured OV/FT cells we identified a normal cell-of-origin gene signature that classified primary ovarian cancers into OV-like and FT-like subgroups; this classification correlated with significant differences in clinical outcomes. The identification of a prognostically significant gene expression signature derived solely from normal untransformed cells is consistent with the hypothesis that the normal cell-of-origin may be a source of ovarian tumor heterogeneity and the associated differences in tumor outcome.

Annexin A4 is involved in proliferation, chemo-resistance and migration and invasion in ovarian clear cell adenocarcinoma cells

Ovarian clear cell adenocarcinoma (CCC) is the second most common subtype of ovarian cancer after high-grade serous adenocarcinomas. CCC tends to develop resistance to the standard platinum-based chemotherapy, and has a poor prognosis when diagnosed in advanced stages. The ANXA4 gene, along with its product, a Ca⁺⁺-binding annexin A4 (ANXA4) protein, has been identified as the CCC signature gene. We reported two subtypes of ANXA4 with different isoelectric points (IEPs) that are upregulated in CCC cell lines. Although several in vitro investigations have shown ANXA4 to be involved in cancer cell proliferation, chemoresistance, and migration, these studies were generally based on its overexpression in cells other than CCC. To elucidate the function of the ANXA4 in CCC cells, we established CCC cell lines whose ANXA4 expressions are stably knocked down. Two parental cells were used: OVTOKO contains almost exclusively an acidic subtype of ANXA4, and OVISE contains predominantly a basic subtype but also a detectable acidic subtype. ANXA4 knockdown (KO) resulted in significant growth retardation and greater sensitivity to carboplatin in OVTOKO cells. ANXA4-KO caused significant loss of migration and invasion capability in OVISE cells, but this effect was not seen in OVTOKO cells. We failed to find the cause of the different IEPs of ANXA4, but confirmed that the two subtypes are found in clinical CCC samples in ratios that vary by patient. Further investigation to clarify the mechanism that produces the subtypes is needed to clarify the function of ANXA4 in CCC, and might allow stratification and improved treatment strategies for patients with CCC.

The role of the fallopian tube in the origin of ovarian cancer

Advanced cases of epithelial ovarian, primary peritoneal, and primary tubal malignancies have a relatively poor prognosis and collectively remain the most deadly of all gynecologic malignancies. Although traditionally thought of as one disease process, ongoing research suggests that there is not 1 single site or cell type from which these cancers arise. A majority of the serous tumors appear to originate from dysplastic lesions in the distal fallopian tube. Therefore, what we have traditionally considered "ovarian" cancer may in fact be tubal in origin. In this article, we will review epithelial ovarian cancer classification and genetics, theories regarding cells of origin with a focus on tubal intraepithelial carcinoma, and implications for prevention and screening.

Expression of folate receptor-α (FRA) in gynecologic malignancies and its relationship to the tumor type

An immunohistochemical evaluation for folate receptor-α (FRA) was undertaken to evaluate expression in gynecologic malignancies involving ovary, endometrium, and the fallopian tube. Commercial tissue microarrays were assessed using an optimized manual immunohistochemical method using MAb 26B3, a newly described monoclonal antibody. A positive result was defined as ≥5% of the sample demonstrating membranous staining. A semiquantitative staining algorithm, defined as the M-score, was used to analyze staining intensity between sample histotypes. MAb 26B3 showed uniform membranous staining and high levels of expression of FRA in ovarian, fallopian tube, and endometrial cancers. All serous ovarian cancers analyzed (70) were positive for FRA expression and no relationship to stage or grade was found. However, a significant difference for FRA expression, between serous and mucinous ovarian carcinomas, was demonstrated (P=0.014). In addition, approximately 90% of all endometrial adenocarcinomas were positive for FRA expression but, unlike ovarian serous carcinomas, a statistically significant relationship to grade was observed (P=0.0029). Although normal ovary is completely devoid of FRA immunoreactivity, normal fallopian tube and cortical serous/tubal inclusion cysts demonstrated uniform and intense FRA staining of columnar epithelium supporting the hypothesis that serous ovarian carcinoma is similar to the tubal epithelium. The data presented further support the hypothesis that FRA expression in gynecologic tumors is due to the cell of origin normally expressing this receptor. This is possibly due to an associated growth advantage, rather than the process of tumorigenesis resulting in aberrant expression of FRA per se.

Precursors and pathogenesis of ovarian carcinoma

The ultimate goal of defining cancer specific precursors is to facilitate early detection and intervention before the development of invasive malignancy. Unlike other malignancies involving the female genital tract such as cervical or endometrial carcinomas, precursor lesions of ovarian carcinomas have not been well characterised, resulting in a failure to develop effective screening programs. Recent clinicopathological and molecular studies have provided new insight into the origin and pathogenesis of ovarian carcinomas. It has been shown that ovarian cancer is comprised of different tumour types differing not only in morphology, but also in pathogenesis, molecular alterations and clinical progression. A dualistic model of ovarian carcinogenesis has been proposed. Type I tumours which include low grade serous, low grade endometrioid, clear cell, mucinous carcinomas and Brenner tumours, are generally indolent and tend to be genetically stable, although clear cell carcinoma would probably belong to an intermediate category. They demonstrate a step-wise progression from a benign precursor such as a benign to borderline tumour or endometriosis and are characterised by genetic aberrations targeting specific cell signalling pathways. Type II tumours comprise high grade serous, high grade endometrioid, and undifferentiated carcinomas as well as malignant mixed mesodermal tumours. They are clinically aggressive and exhibit high genetic instability with frequent p53 mutations. Mounting evidence suggests that many high grade serous carcinomas originate from the epithelium of the distal fallopian tube, and that serous tubal intraepithelial carcinoma (STIC) represents the putative precursor of these neoplasms. Low grade serous carcinomas arise via transformation of benign and borderline serous tumours, thought to be derived from inclusion cysts originating from the ovarian surface or tubal epithelium. Recently it has been suggested that papillary tubal hyperplasia may be a putative precursor lesion for serous borderline tumours. Both endometrioid and clear cell carcinomas develop from endometriosis, via alterations affecting different genetic pathways. The origin of mucinous and transitional cell neoplasms is not well characterised, although new data suggest a possible origin from transitional cell nests present at the tubal-mesothelial junction. Likewise, the pathogenesis of carcinosarcomas is also not well established because of their rarity but there is accumulating evidence that the carcinomatous component determines the course of the disease and gives rise to the malignant mesenchymal component. This review discusses recent developments in the pathogenesis of ovarian carcinoma, with particular emphasis on the putative precursor lesions that give rise to the major histological subtypes. Recognition of these lesions is not only important in improving the understanding of ovarian carcinogenesis, but it will also influence our approach to prevent, detect and treat these tumours.

Predicting time to ovarian carcinoma recurrence using protein markers

Patients with ovarian cancer are at high risk of tumor recurrence. Prediction of therapy outcome may provide therapeutic avenues to improve patient outcomes. Using reverse-phase protein arrays, we generated ovarian carcinoma protein expression profiles on 412 cases from TCGA and constructed a PRotein-driven index of OVARian cancer (PROVAR). PROVAR significantly discriminated an independent cohort of 226 high-grade serous ovarian carcinomas into groups of high risk and low risk of tumor recurrence as well as short-term and long-term survivors. Comparison with gene expression-based outcome classification models showed a significantly improved capacity of the protein-based PROVAR to predict tumor progression. Identification of protein markers linked to disease recurrence may yield insights into tumor biology. When combined with features known to be associated with outcome, such as BRCA mutation, PROVAR may provide clinically useful predictions of time to tumor recurrence.

Origin and pathogenesis of pelvic (ovarian, tubal, and primary peritoneal) serous carcinoma

A new paradigm for the pathogenesis of female pelvic cancer helps explain persistent problems in describing the development and diverse morphology of these neoplasms. This paradigm incorporates recent advances in the molecular pathogenesis of epithelial ovarian cancer (EOC) with new insights into the origin of these tumors. Correlated clinicopathologic and molecular genetic studies gave rise to a dualistic model that divides the various histologic types of EOCs into two broad categories designated type I and type II. Because serous carcinomas are the most common EOC and account for the vast majority of deaths, they form the subject of this review. Recent studies indicate that the precursor of ovarian high-grade serous carcinoma appears to develop from an occult intraepithelial carcinoma in the fimbria of the fallopian tube and involves the ovary secondarily. Another possible mechanism is implantation of normal fimbrial epithelium on the denuded ovarian surface at the site of rupture when ovulation occurs, causing the development of cortical inclusion cysts. The dualistic model serves as a framework for the study of ovarian cancer and can help investigators organize this complex group of neoplasms. It also facilitates the development of novel approaches to prevention, screening, and treatment of this devastating disease.

Mutation analysis of papillary tubal hyperplasia associated with ovarian atypical proliferative serous tumor and low-grade serous carcinoma

We present a patient with ovarian atypical proliferative serous tumor and low-grade serous carcinoma, related to KRAS mutation. Bilateral fallopian tubes had papillary tubal hyperplasia, providing additional evidence that it is the putative precursor of low-grade serous tumors. Mutation analysis of papillary tubal hyperplasia has not been done in previous literature.

Distinct molecular profiles in Lynch syndrome-associated and sporadic ovarian carcinomas

Ovarian carcinoma in Lynch syndrome (LS) is associated with unexpectedly high survival; yet, beyond DNA mismatch repair (MMR) defects, the developmental mechanisms are unknown. We used established (genetic) and new (epigenetic) classifiers of ovarian cancer to explore similarities and differences between LS-associated and sporadic diseases. To this end, all available ovarian carcinomas (n = 20) from MMR gene mutation carriers ascertained through a nation-wide registry and 87 sporadic ovarian carcinomas of the main histological types were molecularly profiled. LS-ovarian carcinomas were mostly of nonserous histology (12 endometrioid, seven clear cell and one serous), diagnosed at a mean age of 45.7 years, and associated with a 10-year survival of 87%. Among LS-ovarian carcinomas, 19/20 (95%) were MMR-deficient vs. 11/87 (13%) among sporadic cases (p < 0.0001). In a striking contrast to the sporadic cases, the expression of p53 was normal and KRAS/BRAF mutations absent in all LS-ovarian carcinomas. PIK3CA mutations, suggested to be a favorable prognostic factor, occurred with a frequency of 6/20 (30%), which was comparable to sporadic tumors of endometrioid or clear cell type. Tumor suppressor genes were more frequently methylated and LINE-1 hypomethylation less common in LS-ovarian carcinomas compared to their sporadic counterparts. The patterns of genetic and epigenetic alterations reflected the origin as LS vs. sporadic cases on one hand and the histological type on the other hand. In conclusion, the significant molecular differences observed between LS-associated and sporadic ovarian carcinomas help explain the different behavior of these tumors and emphasize the need for tailored clinical management.

Origin of ovarian cancer: molecular profiling

This is a review on the transition from our empirical approach to treat ovarian cancer to a specific treatment based on molecular signature. We have reviewed not only the evidence-based medicine focused on the origin and tumor morphology of ovarian cancer but also the molecular signature era based on molecular phenotyping of the tumor and its microenvironment, which influences the direct targeted therapy. Evidence-based medicine has shown that the targeted therapy studies are mainly biomarker driven, more focused, and hence treat only those patients who have the underlying molecular abnormality. This molecular abnormality is the target of the drug, leading to higher rates of response. These findings will carry important implications for screening, detection, and treatment of ovarian cancer in the future.

Salpingectomy as standard at hysterectomy? A Danish cohort study, 1977-2010

OBJECTIVE

To assess if the risk of first-time salpingectomy was affected by prior hysterectomy with retained fallopian tubes and by prior sterilisation.

DESIGN

A historical cohort study.

SETTING

Denmark.

PARTICIPANTS

170 000 randomly selected women born 1947-1963 (10 000/year) were followed from 1977 until the end of 2010.

MAIN OUTCOME MEASURES

Effect of hysterectomy with retained fallopian tubes or sterilisation on the risk of salpingectomy. Both were modelled in a Cox proportional hazards model as time-dependent covariates, analysing time to first salpingectomy. End of follow-up period was 31 December 2010.

RESULTS

Of 9591 hysterectomies, 6456 (67.3%) had both fallopian tubes retained. HRs for salpingectomy after hysterectomy with retained fallopian tubes and sterilisation were 2.13 (95% 1.88 to 2.42) and 2.42 (2.21 to 2.64), as compared with those for non-hysterectomised and non-sterilised women.

CONCLUSIONS

Women undergoing hysterectomy with retained fallopian tubes or sterilisation have at least a doubled risk of subsequent salpingectomy. Removal of the fallopian tubes at hysterectomy should therefore be recommended.

Ovarian cancer: can proteomics give new insights for therapy and diagnosis?

The study of the ovarian proteomic profile represents a new frontier in ovarian cancer research, since this approach is able to enlighten the wide variety of post-translational events (such as glycosylation and phosphorylation). Due to the possibility of analyzing thousands of proteins, which could be simultaneously altered, comparative proteomics represent a promising model of possible biomarker discovery for ovarian cancer detection and monitoring. Moreover, defining signaling pathways in ovarian cancer cells through proteomic analysis offers the opportunity to design novel drugs and to optimize the use of molecularly targeted agents against crucial and biologically active pathways. Proteomic techniques provide more information about different histological types of ovarian cancer, cell growth and progression, genes related to tumor microenvironment and specific molecular targets predictive of response to chemotherapy than sequencing or microarrays. Estimates of specificity with proteomics are less consistent, but suggest a new role for combinations of biomarkers in early ovarian cancer diagnosis, such as the OVA1 test. Finally, the definition of the proteomic profiles in ovarian cancer would be accurate and effective in identifying which pathways are differentially altered, defining the most effective therapeutic regimen and eventually improving health outcomes.

Overexpression of multiple myeloma SET domain (MMSET) is associated with advanced tumor aggressiveness and poor prognosis in serous ovarian carcinoma

Multiple myeloma SET domain (MMSET) has been shown to be overexpressed in many different cancer tissues. Our study was to investigate the expression of MMSET in serous ovarian carcinoma and to evaluate its clinical significance in patients with serous ovarian carcinoma. Immunohistochemistry was performed to determine the expression of MMSET in 132 serous ovarian carcinoma, 32 normal ovarian and fallopian tube specimens. The high expression of MMSET was observed in 49.2% (65/132) in patients with serous ovarian carcinoma. MMSET high expression correlated with the advanced extent of serous ovarian carcinoma and poor outcome. MMSET may serve as a new molecular marker to predict the prognosis of serous ovarian carcinoma in the clinic.

The molecular fingerprint of high grade serous ovarian cancer reflects its fallopian tube origin

High grade serous ovarian cancer (HGSC), the most lethal and frequent type of epithelial ovarian cancer (EOC), has poor long term prognosis due to a combination of factors: late detection, great metastatic potential and the capacity to develop resistance to available therapeutic drugs. Furthermore, there has been considerable controversy concerning the etiology of this malignancy. New studies, both clinical and molecular, strongly suggest that HGSC originates not from the surface of the ovary, but from the epithelial layer of the neighboring fallopian tube fimbriae. In this paper we summarize data supporting the central role of fallopian tube epithelium in the development of HGSC. Specifically, we address cellular pathways and regulatory mechanisms which are modulated in the process of transformation, but also genetic changes which accumulate during disease progression. Similarities between fallopian tube mucosa and the malignant tissue of HGSC warrant a closer analysis of homeostatic mechanisms in healthy epithelium in order to elucidate key steps in disease development. Finally, we highlight the importance of the cancer stem cell (CSC) identification and understanding of its niche regulation for improvement of therapeutic strategies.

Loss of ARID1A expression is an early molecular event in tumor progression from ovarian endometriotic cyst to clear cell and endometrioid carcinoma

OBJECTIVES

ARID1A is a recently identified tumor suppressor participating in chromatin remodeling. Somatic inactivating mutations of ARID1A and loss of its expression occur frequently in ovarian clear cell and endometrioid carcinomas and in uterine endometrioid carcinomas. Because endometriotic epithelium is thought to be the cell of origin of most ovarian clear cell and endometrioid carcinomas, we undertook an analysis of ARID1A expression of these tumors arising within an endometriotic cyst (endometrioma).

MATERIALS AND METHODS

Our immunohistochemical study set consisted of 47 endometriotic cysts containing clear cell carcinoma in 24 cases, well-differentiated ovarian endometrioid carcinoma in 20 cases, and mixed clear cell and endometrioid carcinoma in 3 cases.

RESULTS

ARID1A loss was observed in 31 (66%) of 47 carcinomas; and therefore, these cases were informative for determining the temporal sequence of loss of ARID1A expression in tumor progression. In 16 of the 47 cases, ARID1A immunoreactivity was retained in both the endometriotic cyst and the carcinoma; and thus, these cases were not informative. All of the 31 informative cases showed loss of ARID1A immunoreactivity in the carcinoma and in the endometriotic cyst epithelium in direct continuity with the carcinoma but not in the cyst epithelium that was not adjacent to the tumor.

CONCLUSIONS

Loss of ARID1A function as shown by loss of expression, presumably due to mutations, is an early molecular event in the development of most ovarian clear cell and endometrioid carcinomas arising in endometriomas.

Ovarian epithelial tumors and reproductive factors: a systematic review

PURPOSE

The aim of this systematic review is to summarize the current knowledge about the etiology and pathogenesis of borderline tumors ovarian cancer with special emphasis on the role of endocrine treatments and reproductive factors to establish a foundation for future studies.

METHODS

We performed a systematic review on the relation between ovarian epithelial tumors (OET) and reproductive factors using the keywords: ovarian cancer, ovarian tumor, ovarian borderline tumor, age at menarche, age at menopause, parity, infertility, PCO syndrome, oral contraception, menopausal hormone therapy, fertility treatment. Totally, 3,290 abstracts were scanned for their relevance in this publication and 127 were finally included.

RESULTS

The incidence of ovarian epithelial cancer and ovarian borderline tumors is influenced by certain reproductive factors. The strongest protective effects are conferred by parity and use of oral contraceptive pills. Recent molecular biologic and histopathologic studies prove that OET represent a diverse group of tumors, each histologic type with a different genetic background. This is at least partly reflected in epidemiologic and clinical studies showing different risk modulating effects of reproductive factors and endocrine therapies on OET.

CONCLUSIONS

The etiology and pathogenesis of ovarian cancer are still not fully understood. None of the so far proposed hypothesis on the development of OET can fully account for the epidemiologic and clinical findings in the context of reproductive factors and OET development. Further research approaches are warranted and need to put more weight on the clinical and genetical diversity of OET to yield a more detailed insight into their pathogenesis.

PAX8 is a novel marker for differentiating between various types of tumor, particularly ovarian epithelial carcinomas

Paired-box gene 8 (PAX8) encodes a transcription factor associated with important roles in embryogenesis and disease, and is a member of the PAX gene family. PAX8 has been demonstrated to be crucial in determining cell fate during the development of the thyroid, kidney, brain, eyes and Müllerian system and regulates expression of the Wilms’ tumor suppressor gene (WT1). Several previous studies have reported that PAX8 is expressed at high levels in specific types of tumor, including thyroid and renal carcinomas and pancreatic neuroendocrine tumors. In addition, PAX8 has been reported to be useful for the detection and differential diagnosis of ovarian carcinoma. The consistency of PAX8 staining in epithelial ovarian carcinomas (EOCs) and the fallopian tube has provided morphological evidence that EOC may originate from the fallopian tube. The molecular mechanism of PAX8 in the carcinogenesis of these tumors remains unclear and requires further studies.

High-Grade Serous Tumor Arising from Fallopian Tube in a BRCA Mutation Carrier after Prophylactic Oophorectomy

We present the case of a 67-year-old patient with a BRCA1 mutation and breast cancer who underwent prophylactic oophorectomy. After 6 years, an abdominal computed tomography revealed a pelvic mass which proved to be a poorly differentiated serous carcinoma originating from the right residual tube which previously had not been removed during prophylactic surgery. This case report suggests that much effort should be made during prophylactic oophorectomy to completely remove the tubes, especially in light of the recent pathologic theories on the tubal origin of ovarian cancer.

Pathogenesis and the role of ARID1A mutation in endometriosis-related ovarian neoplasms

Endometriosis-related ovarian neoplasms (ERONs) are a unique group of tumors as they are associated with endometriosis, especially endometriosis presenting as an ovarian endometriotic cyst (endometrioma). ERONs include clear cell carcinoma, endometrioid carcinoma, and seromucinous borderline tumor. A growing body of evidence from both clinicopathologic and molecular studies suggests that most, if not all, ERONs develop from endometriotic cyst epithelium through different stages of tumor progression. The endometriotic cyst contains abundant iron-induced reactive oxygen species that are thought to be mutagenic, and chronic exposure of cystic epithelium to this microenvironment facilitates the accumulation of somatic mutations that ultimately result in tumor development. Molecular analyses of ERONs, including genome-wide screens, have identified several molecular genetic alterations that lead to aberrant activation or inactivation of pathways involving ARID1A, PI3K, Wnt, and PP2A. Among all molecular genetic changes identified to date, inactivating mutations of the ARID1A tumor suppressor gene are the most common in ERON. Understanding the molecular changes and pathogenesis involved in the development of ERON is fundamental for future translational studies aimed at designing new diagnostic tests for early detection and identifying critical molecular features for targeted therapeutics.

Prognostically relevant gene signatures of high-grade serous ovarian carcinoma

Because of the high risk of recurrence in high-grade serous ovarian carcinoma (HGS-OvCa), the development of outcome predictors could be valuable for patient stratification. Using the catalog of The Cancer Genome Atlas (TCGA), we developed subtype and survival gene expression signatures, which, when combined, provide a prognostic model of HGS-OvCa classification, named "Classification of Ovarian Cancer" (CLOVAR). We validated CLOVAR on an independent dataset consisting of 879 HGS-OvCa expression profiles. The worst outcome group, accounting for 23% of all cases, was associated with a median survival of 23 months and a platinum resistance rate of 63%, versus a median survival of 46 months and platinum resistance rate of 23% in other cases. Associating the outcome prediction model with BRCA1/BRCA2 mutation status, residual disease after surgery, and disease stage further optimized outcome classification. Ovarian cancer is a disease in urgent need of more effective therapies. The spectrum of outcomes observed here and their association with CLOVAR signatures suggests variations in underlying tumor biology. Prospective validation of the CLOVAR model in the context of additional prognostic variables may provide a rationale for optimal combination of patient and treatment regimens.

The role of forkhead box Q1 transcription factor in ovarian epithelial carcinomas

The role of the forkhead box Q1 (FOXQ1) transcription factor in cancer pathogenesis has recently emerged. Overexpression of FOXQ1 has been found in a variety of human cancers, and its upregulation has been associated with poor prognosis in colorectal, breast, and non-small cell lung carcinomas. However, the molecular mechanism underlying how FOXQ1 contributes to ovarian epithelial carcinomas remains unclear. To this end, we analyzed gene expression levels in ovarian cancer tissues and cell lines and demonstrated a higher expression level of FOXQ1 in epithelial ovarian cancer cells than that in normal epithelial cells. We then used a human ovarian cancer cell line, SKOV3, which expressed a higher level of FOXQ1, as a cell model to investigate the biological effects of FOXQ1 by using RNA interference. Silencing of FOXQ1 expression using a shRNA knockdown approach affected the expression of several cell cycle regulators, leading to suppressed cell proliferation, reduced cell motility/invasion, and upregulation of epithelial cell markers and the downregulation of mesenchymal cell markers. Taken together, these results suggest that FOXQ1 expression is essential to maintain cell proliferation, motility/invasion, and epithelial-mesenchymal transition phenotypes in ovarian cancer cells.