Altered surface and cyst epithelium of ovaries removed prophylactically from women with a family history of ovarian cancer

The Transcoelomic Ecosystem and Epithelial Ovarian Cancer Dissemination

Epithelial ovarian cancer (EOC) is considered the deadliest gynecological disease and is normally diagnosed at late stages, at which point metastasis has already occurred. Throughout disease progression, EOC will encounter various ecosystems and the communication between cancer cells and these microenvironments will promote the survival and dissemination of EOC. The primary tumor is thought to develop within the ovaries or the fallopian tubes, both of which provide a microenvironment with high risk of causing DNA damage and enhanced proliferation. EOC disseminates by direct extension from the primary tumors, as single cells or multicellular aggregates. Under the influence of cellular and non-cellular factors, EOC spheroids use the natural flow of peritoneal fluid to reach distant organs within the peritoneal cavity. These cells can then implant and seed distant organs or tissues, which develop rapidly into secondary tumor nodules. The peritoneal tissue and the omentum are two common sites of EOC metastasis, providing a microenvironment that supports EOC invasion and survival. Current treatment for EOC involves debulking surgery followed by platinum-taxane combination chemotherapy; however, most patients will relapse with a chemoresistant disease with tumors developed within the peritoneum. Therefore, understanding the role of the unique microenvironments that promote EOC transcoelomic dissemination is important in improving patient outcomes from this disease. In this review article, we address the process of ovarian cancer cellular fate at the site of its origin in the secretory cells of the fallopian tube or in the ovarian surface epithelial cells, their detachment process, how the cells survive in the peritoneal fluid avoiding cell death triggers, and how cancer- associated cells help them in the process. Finally, we report the mechanisms used by the ovarian cancer cells to adhere and migrate through the mesothelial monolayer lining the peritoneum. We also discuss the involvement of the transcoelomic ecosystem on the development of chemoresistance of EOC.

Mutated p53 in HGSC-From a Common Mutation to a Target for Therapy

Simple Summary

Ovarian high-grade serous cancer (HGSC), the most common and the deadliest subtype of epithelial ovarian cancer, is characterized by frequent mutations in the TP53 tumor suppressor gene, encoding for the p53 protein in nearly 100% of cases. This makes p53 the focus of many studies trying to understand its role in HGSC. The aim of our review paper is to provide updates on the latest findings related to the role of mutant p53 in HGSC. This includes the clinical outcomes of TP53 mutations in HGSC, upstream regulators and downstream effectors of p53, its function in the earliest stages of HGSC development and in the interplay between the tumor cells and their microenvironment. We summarize with the likelihood of p53 mutants to serve as biomarkers for early diagnosis and as targets for therapy in HGSC.

Abstract

Mutations in tumor suppressor gene TP53, encoding for the p53 protein, are the most ubiquitous genetic variation in human ovarian HGSC, the most prevalent and lethal histologic subtype of epithelial ovarian cancer (EOC). The majority of TP53 mutations are missense mutations, leading to loss of tumor suppressive function of p53 and gain of new oncogenic functions. This review presents the clinical relevance of TP53 mutations in HGSC, elaborating on several recently identified upstream regulators of mutant p53 that control its expression and downstream target genes that mediate its roles in the disease. TP53 mutations are the earliest genetic alterations during HGSC pathogenesis, and we summarize current information related to p53 function in the pathogenesis of HGSC. The role of p53 is cell autonomous, and in the interaction between cancer cells and its microenvironment. We discuss the reduction in p53 expression levels in tumor associated fibroblasts that promotes cancer progression, and the role of mutated p53 in the interaction between the tumor and its microenvironment. Lastly, we discuss the potential of TP53 mutations to serve as diagnostic biomarkers and detail some more advanced efforts to use mutated p53 as a therapeutic target in HGSC.

Ovarian BDNF promotes survival, migration, and attachment of tumor precursors originated from p53 mutant fallopian tube epithelial cells

High-grade serous ovarian carcinoma (HGSOC) is the most lethal gynecological malignancy. New evidence supports a hypothesis that HGSOC can originate from fallopian tube epithelium (FTE). It is unclear how genetic alterations and pathophysiological processes drive the progression of FTE tumor precursors into widespread HGSOCs. In this study, we uncovered that brain-derived neurotrophic factor (BDNF) in the follicular fluid stimulates the tropomyosin receptor kinase B (TrkB)-expressing FTE cells to promote their survival, migration, and attachment. Using in vitro and in vivo models, we further identified that the acquisition of common TP53 gain-of-function (GOF) mutations in FTE cells led to enhanced BDNF/TrkB signaling compared to that of FTE cells with TP53 loss-of-function (LOF) mutations. Different mutant p53 proteins can either increase TrkB transcription or enhance TrkB endocytic recycling. Our findings have demonstrated possible interplays between genetic alterations in FTE tumor precursors (i.e., p53 GOF mutations) and pathophysiological processes (i.e., the release of follicular fluid upon ovulation) during the initiation of HGSOC from the fallopian tube. Our data revealed molecular events underlying the link between HGSOC tumorigenesis and ovulation, a physiological process that has been associated with risk factors of HGSOC.

Ovulation and ovarian wound healing are impaired with advanced reproductive age

Aging is associated with reduced tissue remodeling efficiency and increased fibrosis, characterized by excess collagen accumulation and altered matrix degradation. Ovulation, the process by which an egg is released from the ovary, is one of the most dynamic cycles of tissue wounding and repair. Because the ovary is one of the first organs to age, ovulation and ovarian wound healing is impaired with advanced reproductive age. To test this hypothesis, we induced superovulation in reproductively young and old mice and determined the numbers of eggs ovulated and corpora lutea (CLs), the progesterone producing glands formed post-ovulation. Reproductively old mice ovulated fewer eggs and had fewer CLs relative to young controls. Moreover, reproductively old mice exhibited a greater number of oocytes trapped within CLs and expanded cumulus oocyte complexes within unruptured antral follicles, indicative of failed ovulation. In addition, post-ovulatory tissue remodeling was compromised with age as evidenced by reduced CL vasculature, increased collagen, decreased hyaluronan, decreased cell proliferation and apoptosis, impaired wound healing capacity, and aberrant morphology of the ovarian surface epithelium (OSE). These findings demonstrate that ovulatory dysfunction is an additional mechanism underlying the age-related loss of fertility beyond the reduction of egg quantity and quality.

Age related increase in mTOR activity contributes to the pathological changes in ovarian surface epithelium

Ovarian cancer is a disease of older women. However, the molecular mechanisms of ovarian aging and their contribution to the pathogenesis of ovarian cancer are currently unclear. mTOR signalling is a major regulator of aging as suppression of this pathway extends lifespan in model organisms. Overactive mTOR signalling is present in up to 80% of ovarian cancer samples and is associated with poor prognosis. This study examined the role of mTOR signalling in age-associated changes in ovarian surface epithelium (OSE). Histological examination of ovaries from both aged mice and women revealed OSE cell hyperplasia, papillary growth and inclusion cysts. These pathological lesions expressed bonafide markers of ovarian cancer precursor lesions, Pax8 and Stathmin 1, and were presented with elevated mTOR signalling. To understand whether overactive mTOR signalling is responsible for the development of these pathological changes, we analysed ovaries of the Pten trangenic mice and found significant reduction in OSE lesions compared to controls. Furthermore, pharmacological suppression of mTOR signalling significantly decreased OSE hyperplasia in aged mice. Treatment with mTOR inhibitors reduced human ovarian cancer cell viability, proliferation and colony forming ability. Collectively, we have established the role of mTOR signalling in age-related OSE pathologies and initiation of ovarian cancer.

Molecular analysis of high-grade serous ovarian carcinoma with and without associated serous tubal intra-epithelial carcinoma

Many high-grade serous carcinomas (HGSCs) of the pelvis are thought to originate in the distal portion of the fallopian tube. Serous tubal intra-epithelial carcinoma (STIC) lesions are the putative precursor to HGSC and identifiable in ~ 50% of advanced stage cases. To better understand the molecular etiology of HGSCs, we report a multi-center integrated genomic analysis of advanced stage tumors with and without STIC lesions and normal tissues. The most significant focal DNA SCNAs were shared between cases with and without STIC lesions. The RNA sequence and the miRNA data did not identify any clear separation between cases with and without STIC lesions. HGSCs had molecular profiles more similar to normal fallopian tube epithelium than ovarian surface epithelium or peritoneum. The data suggest that the molecular features of HGSCs with and without associated STIC lesions are mostly shared, indicating a common biologic origin, likely to be the distal fallopian tube among all cases.High-grade serous carcinomas (HGSCs) are associated with precursor lesions (STICs) in the fallopian epithelium in only half of the cases. Here the authors report the molecular analysis of HGSCs with and without associated STICs and show similar profiles supporting a common origin for all HGSCs.

BRCA1 expression, proliferative and apoptotic activities in ovarian epithelial inclusions

BACKGROUND

The purpose of this study was to examine proliferative and apoptotic activity in relation with BRCA1 expression in ovarian epithelial inclusions (OEIs), the putative precursor lesions of ovarian epithelial cancer (OEC).

METHODS

Benign ovaries from 95 patients were examined. Dual immunohistochemical staining for both BRCA1 and MIB-1 were performed to examine the relationship between BRCA1 and MIB-1 in OEI cells. Apoptotic activity was assessed on the parallel tissue sections by using TUNEL assay. Patients' age, menstrual phase and menopausal status were analyzed.

RESULTS

OEIs were present in the ovaries of 53% of the patients. OEIs were less frequently found in premenopausal (45%) than postmenopausal women (58%). BRCA1 and MIB-1 were found in 27 and 47% of the OEI-containing ovaries, respectively. All BRCA1 positive OEI cells are MIB-1 positive with dual staining method, although overall the percentage of positive cells was small. No significant difference was found for BRCA1 and MIB-1 expression in OEIs between menopausal status and menstrual phases. Apoptosis containing OEIs were seen in 70% of the ovaries. Compared to OEIs in proliferative menstrual phase and premenopausal status, significantly more apoptosis was found in OEIs from secretory phase and postmenopausal women. A small fraction of the epithelial cells within OEIs are proliferating or dying.

CONCLUSIONS

Low estrogen and/or high progesterone levels may promote OEI cell turnover via induction of apoptosis. Imbalance between cell proliferation and death within OEIs under influence of hormones may play a role in the ovarian epithelial tumorigenesis.

[Prophylactic salpingectomy or salpingo-oophorectomy as an ovarian cancer prevention?]

A recent hypothesis has stated that many ovarian cancers (especially high-grade serous histotype) could arise from the distal part of the fallopian tube. On one hand we know that risk-reducing salpingo-oophorectomy is the most effective prevention for ovarian cancer among BRCA mutation carriers. On the other, oophorectomy increases the relative risk for cardiovascular, osteoporotic psychosexual and cognitive dysfunctions in premenopausal women. This raises the question whether bilateral salpingectomy could be an effective strategy in the prevention of ovarian cancer in case of hereditary predisposition and in the general population. Here we discuss origin of ovarian cancer in the light of the latest molecular studies and the relative risks and benefits of a strategy of exclusive salpingectomy in comparison with the classical adnexectomy.

Morphological and immunohistochemical pattern of tubo-ovarian dysplasia and serous tubal intraepithelial carcinoma

OBJECTIVE

Histopathological examination of material from prophylactic salpingo-oophorectomies performed in patients at genetic risk of ovarian cancer can reveal abnormalities interpreted as possible pre-cancerous "ovarian dysplasia" and tubal precursors lesions. We sought to study the morphological features and immunohistochemical expression patterns of neoplasia-associated markers in prophylactically removed ovaries and fallopian tubes (pBSO) in comparison with a group of serous tubal intraepithelial carcinoma (STIC) and non-cancerous controls.

STUDY DESIGN

Morphological features and immunohistochemical expression patterns of Ki-67 (for proliferation biomarker), p53 (key pathway of mullerian serous tumorogenesis), Bcl2 (anti-apoptotic), γH2AX (a double-strand breaks marker) and ALDH1 (a stem cell marker significantly associated with early-stage ovarian cancer) were blindly evaluated by two pathologists in 111 pBSO, 12 STICs and 116 non-cancerous salpingo-oophorectomies (control group) (nBSO).

RESULTS

Morphological ovarian and tubal dysplasia scores were significantly higher in the pBSO than in controls (respectively, 8.8 vs 3.12, p<0.0001, for ovaries and 6.54 vs 1.58, p<0.0001 for tubes). Increased γH2AX expression was observed in the pBSO and STICs compared with the controls whereas expression patterns of Ki67, p53 and bcl2 were low to moderate in the pBSO group. STICs overexpressed Ki67 and p53 while bcl2 expression was low; Interestingly, ALDH1 expression was low in non dysplastic epithelium, high in dysplasia and constantly low in STICs.

CONCLUSION

The morphological and immunohistochemical profile of tubo-ovarian dysplasia and STICs might be consistent with progression toward neoplastic transformation in the Serous Carcinogenesis Sequence. These changes may be pre-malignant and could represent an important phase in early neoplasia. ALDH1 activation in pBSO samples and its extinction in STICs should be considered as a target for prevention.

Coming into focus: the nonovarian origins of ovarian cancer

BACKGROUND

The traditional view of epithelial ovarian cancer asserts that all tumor subtypes share a common origin in the ovarian surface epithelium (OSE) DESIGN: A literature review was carried out to summarize the emerging understanding of extraovarian sources of epithelial ovarian carcinomas.

RESULTS

Historically, there were no diagnostic criteria for documenting the origin of ovarian epithelial carcinomas. Moreover, there are no normal epithelial tissues in the ovary with morphologic similarities to these tumors. In fact, no precursor lesions have ever been reproducibly identified in the ovary. However, there is a strong correlation between extrauterine Müllerian tissue and the development of ovarian carcinomas, tumors of low malignant potential, and cystadenomas. The most recent support for this hypothesis comes from the careful analysis of risk-reducing bilateral salpingo-oopherectomy specimens from BRCA1 or BRCA2 mutation carriers. These studies showed that a significant majority of high-grade serous ovarian carcinomas, the most common subtype, arise from the fallopian tube fimbriae rather than the OSE.

CONCLUSIONS

Mounting evidence indicates that the vast majority of epithelial ovarian carcinomas are not ovarian in origin. Extrauterine Müllerian epithelium from various sites in the reproductive tract likely accounts for the diverse morphology and behavior of these tumors.

Morphological and immunohistochemical study of ovarian and tubal dysplasia associated with tamoxifen

Ovarian epithelial dysplasia was initially described in material from prophylactic oophorectomies for BReast CAncer gene (BRCA) mutation. Similar histopathological abnormalities have been revealed after ovulation stimulation. Given that tamoxifen (TAM) has a clomid-like effect and is sometimes used to induce ovulation, we studied the morphological features and immunohistochemical expression patterns of neoplasia-associated markers in adnexectomies previously exposed to TAM for breast cancer. We blindly reviewed 173 histopathological slides of adnexectomies according to three groups – oophorectomies associated with TAM exposure (n=42), oophorectomies associated with clomiphene exposure (n=15) and a spontaneously fertile non cancerous control group (n=116). Morphological features (with an ovarian and tubal dysplasia scoring system) and immunohistochemical expression patterns of Ki-67, p53 and Aldehyde dehydrogenase 1 (ALDH1 is an enzyme significantly associated with earlystage ovarian cancer) were evaluated and correlated. Mean tubal dysplasia score was significantly higher in the TAM group and clomiphen group than in controls (respectively 7.8 vs 3.5, P<0.007 and 6.8 vs 3.5, P=0.008). There is no statistical difference for the ovarian score in TAM group in comparison with the control group whereas we found a significant score for clomiphen group (6.5, P=0.009). Increased ALDH1 expression was observed in the two exposed group whereas expression patterns of Ki67 and p53 were moderate. Interestingly, ALDH1 expression was low in non-dysplastic epithelium, high in dysplasia, and constantly low in the two carcinoma.

Furthemore, we confirm our previous results showing that ALDH1 may be a useful tissue biomarker in the subtle histopathological diagnosis of tubo-ovarian dysplasia.

Early preinvasive lesions in ovarian cancer

Faced with the catastrophic prognosis for ovarian cancer due to the fact that it is most often diagnosed late at the peritoneal carcinomatosis stage, screening and early detection could probably reduce the mortality rate. A better understanding of the molecular characteristics of the different ovarian cancer subtypes and their specific molecular signatures is indispensable prior to development of new screening strategies. We discuss here the early natural history of ovarian cancer and its origins.

Development of a mouse model of menopausal ovarian cancer

Despite significant understanding of the genetic mutations involved in ovarian epithelial cancer and advances in genomic approaches for expression and mutation profiling of tumor tissues, several key questions in ovarian cancer biology remain enigmatic: the mechanism for the well-established impact of reproductive factors on ovarian cancer risk remains obscure; cell of origin of ovarian cancer continue to be debated; and the precursor lesion, sequence, or events in progression remain to be defined. Suitable mouse models should complement the analysis of human tumor tissues and may provide clues to these questions currently perplexing ovarian cancer biology. A potentially useful model is the germ cell-deficient Wv (white spotting variant) mutant mouse line, which may be used to study the impact of menopausal physiology on the increased risk of ovarian cancer. The Wv mice harbor a point mutation in c-Kit that reduces the receptor tyrosine kinase activity to about 1–5% (it is not a null mutation). Homozygous Wv mutant females have a reduced ovarian germ cell reservoir at birth and the follicles are rapidly depleted upon reaching reproductive maturity, but other biological phenotypes are minimal and the mice have a normal life span. The loss of ovarian function precipitates changes in hormonal and metabolic activity that model features of menopause in humans. As a consequence of follicle depletion, the Wv ovaries develop ovarian tubular adenomas, a benign epithelial tumor corresponding to surface epithelial invaginations and papillomatosis that mark human ovarian aging. Ongoing work will test the possibility of converting the benign epithelial tubular adenomas into neoplastic tumors by addition of an oncogenic mutation, such as of Tp53, to model the genotype and biology of serous ovarian cancer. Model based on the Wv mice may have the potential to gain biological and etiological insights into ovarian cancer development and prevention.

Tu-be or not tu-be: that is the question… about serous ovarian carcinogenesis

Our understanding of the early natural history of epithelial ovarian carcinoma is limited by the access to early lesions as the disease is very often diagnosed at advanced stages. The incessant ovulation theory from the last century that indicated the ovary as the site for the initiation of high-grade serous cancers is contrary to the newly emerging idea that ovarian cancer could arise from the distal fallopian tube. In view of the recent pathological and molecular studies, we propose to discuss the genesis of high-grade serous ovarian cancer.

Tubo-ovarian dysplasia in relationship with ovulation induction in rats

OBJECTIVE

To assess tubo-ovarian dysplasia via morphologic and immunohistochemical study of rats exposed to ovulation stimulation protocols.

DESIGN

Animal experimental study.

SETTING

Academic research hospital.

ANIMAL(S)

72 female Wistar rats divided into three groups.

INTERVENTION(S)

Stimulation protocols using follicle-stimulating hormone (FSH) or clomiphene citrate for 3, 6, or 12 cycles, after which the animals were killed.

MAIN OUTCOME MEASURE(S)

Ovarian and tubal dysplasia score and immunohistochemical assessment using p53 and Ki67.

RESULT(S)

The ovarian dysplasia score was statistically significantly higher after 12 stimulation cycles in the groups receiving FSH (group B) or clomiphene citrate (group C) compared with control (group A). The tubal dysplasia score was statistically significantly increased after only three stimulation cycles in groups B and C. The Ki67 proliferation marker was statistically significantly expressed in the ovaries from group C, and in the fallopian tubes from groups B and C. P53 was constantly low in all three groups.

CONCLUSION(S)

Ovulation stimulation may induce tubal and ovarian histopathologic and immunohistochemical abnormalities with a dose effect. The role of the fallopian tubes and their interaction with the ovaries require further study.

Surgical implications of the potential new tubal pathway for ovarian carcinogenesis

Since 2001, many studies by different investigators have demonstrated that the fallopian tube might be at the origin of most high-grade ovarian and peritoneal serous carcinomas. Simple changes in surgical practice (ie, prophylactic bilateral salpingectomy instead of salpingo-oophorectomy) could have significant implications for death from ovarian cancer and, on the other hand, for the morbidity caused by ovariectomy (surgical menopause). In this review, we describe the new tubal carcinogenic sequence, the advantages and disadvantages of exclusive use of salpingectomy in the general population, and in cases of hereditary predisposition to ovarian cancer such as for carriers of BRCA mutation.

Toxicogenomic evaluation of chemically induced chromosomal imbalance using DNA image analysis

The study of carcinogenic potential of a variety of chemical agents such as food additives and drugs of abuse via the application of various in vitro methodologies constitutes the first step for the evaluation of their toxicogenomic profile. Considering the chromosomal theories of carcinogenesis, where it is stated that aneuploidy and chromosomal imbalance (instability) are among the main causes of carcinogenesis, chemicals capable to induce such changes in the cells could be considered as potential carcinogens. Chromosomal imbalance and aneuploidy directly affect the overall DNA content of the exposed cell as well as other cellular morpho- and densitometric features. These features can be measured by means of computerized DNA image analysis technologies and include DNA content (DNA Index), Proliferation Index, Ploidy Balance, Degree of Aneuploidy, Skewness and Kurtosis. Considering the enormous number of untested chemicals and drugs of abuse that follow non-genotoxic mechanisms of carcinogenesis, the establishment of a reliable technology for the estimation of chemically induced chromosomal imbalance is of particular importance in toxicogenomic studies. In the present article and based on our previously published work, we highlight the advantages of the applications of DNA image analysis technology in an easy-to-use experimental model for the evaluation of the potential risk of various chemicals. The use of this technology for the detection of chemically induced chromosomal instability will contribute to the development of safer regulatory directives concerning the use of chemicals in food and pharmaceutical industry, as well as in the clarification of mechanisms of action of drugs of abuse.

Is There a Relationship between Ovarian Epithelial Dysplasia and Infertility?

Aim. Ovarian epithelial dysplasia was initially described in material from prophylactic oophorectomies performed in patients at genetic risk of ovarian cancer. Similar histopathological abnormalities have been revealed after ovulation stimulation. Since infertility is also a risk factor for ovarian neoplasia, the aim of this study was to study the relationship between infertility and ovarian dysplasia. Methods. We blindly reviewed 127 histopathological slides of adnexectomies or ovarian cystectomies according to three groups-an exposed group to ovulation induction (n = 30), an infertile group without stimulation (n = 35), and a spontaneously fertile control group (n = 62)-in order to design an eleven histopathological criteria scoring system. Results. The ovarian dysplasia score was significantly higher in exposed group whereas dysplasia score was low in infertile and control groups (resp., 8.21 in exposed group, 3.69 for infertile patients, and 3.62 for the controls). In the subgroup with refractory infertility there was a trend towards a more severe dysplasia score (8.53 in ovulation induction group and 5.1 in infertile group). Conclusion. These results raise questions as to the responsibility of drugs used to induce ovulation and/or infertility itself in the genesis of ovarian epithelial dysplasia.

Ovarian Cancer Is an Imported Disease: Fact or Fiction?

The cell of origin of ovarian cancer has been long debated. The current paradigm is that epithelial ovarian cancer (EOC) arises from the ovarian surface epithelium (OSE). OSE is composed of flat, nondescript cells more closely resembling the mesothelium lining the peritoneal cavity, with which it is continuous, rather than the various histologic types of ovarian carcinoma (serous, endometrioid, and clear cell carcinoma), which have a Müllerian phenotype. Accordingly, it has been argued that the OSE undergoes a process termed "metaplasia" to account for this profound morphologic transformation. Recent molecular and clinicopathologic studies not only have failed to support this hypothesis but also have provided evidence that EOC stems from Müllerian-derived extraovarian cells that involve the ovary secondarily, thereby calling into question the very existence of primary EOC. This new model of ovarian carcinogenesis proposes that fallopian tube epithelium (benign or malignant) implants on the ovary to give rise to both high-grade and low-grade serous carcinomas, and that endometrial tissue implants on the ovary and produces endometriosis, which can undergo malignant transformation into endometrioid and clear cell carcinoma. Thus, ultimately EOC is not ovarian in origin but rather is secondary, and it is logical to conclude that the only true primary ovarian neoplasms are germ cell and gonadal stromal tumors analogous to tumors in the testis. If this new model is confirmed, it has profound implications for the early detection and treatment of "ovarian cancer."

Molecular pathogenesis and extraovarian origin of epithelial ovarian cancer--shifting the paradigm

Recent morphologic, immunohistochemical, and molecular genetic studies have led to the development of a new paradigm for the pathogenesis and origin of epithelial ovarian cancer based on a dualistic model of carcinogenesis that divides epithelial ovarian cancer into 2 broad categories designated types I and II. Type I tumors comprise low-grade serous, low-grade endometrioid, clear cell and mucinous carcinomas, and Brenner tumors. They are generally indolent, present in stage I (tumor confined to the ovary), and are characterized by specific mutations, including KRAS, BRAF, ERBB2, CTNNB1, PTEN, PIK3CA, ARID1A, and PPP2R1A, which target specific cell signaling pathways. Type I tumors rarely harbor TP53 mutations and are relatively stable genetically. Type II tumors comprise high-grade serous, high-grade endometrioid, malignant mixed mesodermal tumors (carcinosarcomas), and undifferentiated carcinomas. They are aggressive, present in advanced stage, and have a very high frequency of TP53 mutations but rarely harbor the mutations detected in type I tumors. In addition, type II tumors have molecular alterations that perturb expression of BRCA either by mutation of the gene or by promoter methylation. A hallmark of these tumors is that they are genetically highly unstable. Recent studies strongly suggest that fallopian tube epithelium (benign or malignant) that implants on the ovary is the source of low-grade and high-grade serous carcinoma rather than the ovarian surface epithelium as previously believed. Similarly, it is widely accepted that endometriosis is the precursor of endometrioid and clear cell carcinomas and, as endometriosis, is thought to develop from retrograde menstruation; these tumors can also be regarded as involving the ovary secondarily. The origin of mucinous and transitional cell (Brenner) tumors is still not well established, although recent data suggest a possible origin from transitional epithelial nests located in paraovarian locations at the tuboperitoneal junction. Thus, it now appears that type I and type II ovarian tumors develop independently along different molecular pathways and that both types develop outside the ovary and involve it secondarily. If this concept is confirmed, it leads to the conclusion that the only true primary ovarian neoplasms are gonadal stromal and germ cell tumors analogous to testicular tumors. This new paradigm of ovarian carcinogenesis has important clinical implications. By shifting the early events of ovarian carcinogenesis to the fallopian tube and endometrium instead of the ovary, prevention approaches, for example, salpingectomy with ovarian conservation, may play an important role in reducing the burden of ovarian cancer while preserving hormonal function and fertility.

[Ovarian epithelial dysplasia: Description of a dysplasia scoring scheme]

INTRODUCTION

Precancerous ovarian epithelial dysplasia was first described after prophylactic oophorectomy (OP) for genetic risk (BRCA mutation) or because of a strong family history of ovarian and/or breast cancer. The objective of this study was to describe histopathological features of ovarian dysplasia and to propose a dysplasia scoring sheme with a cut-off.

PATIENTS AND METHOD

One hundred and twenty-five bilateral oophorectomies (genetic predisposition: n=35 and control group: n=90) were reviewed by two pathologists blinded to clinical data. Eleven epithelial cytological and architectural features were studied and an ovarian dysplasia score was defined to compare the degree of ovarian epithelial abnormalities between the two groups.

RESULTS

Mean ovarian dysplasia score was significantly higher in prophylactic oophorectomy group than in control group (9.0 versus 3.5, P<0.001). Dysplasia was more severe in OP with BRCA mutation than in OP without (11.6 in BRCA 1; 7.6 in BCRA 2; 7.1 in family history). The cut off for dysplasia was 8 with a sensitivity of 60% and a specificity of 93.3%.

CONCLUSION

The increased dysplasia score in OP and the gradation in dysplastic severity in OP with proven BRCA mutations may suggest that ovarian dysplasia could be a pre-malignant non invasive histopathological lesion. The 11 cytological and architectural features in the dysplasia scoring sheme could be a useful tool to study ovarian dysplasia.

Effect of cocaine and crack on the ploidy status of Tetrahymena pyriformis: a study using DNA image analysis

The effect of cocaine and crack on the ploidy status of Feulgen-stained Tetrahymena pyriformis macronuclei using computerized DNA image analysis system was tested. For this purpose, selected doses of 5, 10 and 20 μg (per mL culture) of both drugs were administered for 2, 5 and 20 h to protozoa cultures and DNA image analysis of T. pyriformis nuclei was performed. The analysis was based on the measurement of the following parameters: Ploidy Balance (PB), Degree of Aneuploidy (DA), skewness and kurtosis. The results have shown a positive effect of both cocaine and crack on PB and on DA of T. pyriformis macronuclei. In particular, our results reveal that the aneugenic effect (which is expressed as a decrease in PB and an increase in DA) of cocaine on T. pyriformis macronuclei follows a dose-dependent manner, while crack induces aneuploidy in a dose-independent manner. Changes in the PB and DA values would induce a disturbance in the cellular density and heterogeneity of chromatin and the increase in skewness and kurtosis values after exposure of T. pyriformis to both drugs, did confirm this hypothesis. These observations were further correlated with alterations in the chromosomal segregation and with damage in mitotic spindle microtubules observed previously. In this study the impact of cocaine and crack on genomic instability and carcinogenesis was further supported and T. pyriformis can be proposed as a model organism to test the nuclear ploidy status after exposure to harmful chemicals and drugs.

Peri- and post-menopausal incidental adnexal masses and the risk of sporadic ovarian malignancy: new insights and clinical management

Adnexal masses are common among peri- and post-menopausal women. Although ovarian cancer is a significant cause of mortality in menopausal women, large population-based studies demonstrate that the majority of adnexal masses are benign. Despite this, the appearance of an adnexal mass is a concern for the patient and an insight exercise for physicians. In most cases, an adnexal enlargement is an incidental finding, generally corresponding to a benign cyst and easily diagnosed by conventional ultrasound. Exceptionally an ovarian tumour may be malignant and should be treated as early as possible. When conventional ultrasound renders complex morphology other diagnostic tools must be used such as: colour Doppler and functional tumour vessel properties, serum CA 125 levels, nuclear magnetic resonance imaging and in some cases laparoscopy. Several new tumour markers are being studied for clinical application, although there are presently no clear recommendations. Adnexal masses with benign morphological and functional properties must be periodically monitored as an alternative to surgery since malignant transformation is exceptional.

BRCA1 16 years later: risk-associated BRCA1 mutations and their functional implications

Mutations in the tumor suppressor breast cancer susceptibility gene 1 (BRCA1), an important player in the DNA damage response, apoptosis, cell cycle regulation and transcription, confer a significantly elevated lifetime risk for breast and ovarian cancer. Although the loss of wild-type BRCA1 function is an important mechanism by which mutations confer increased cancer risk, multiple studies suggest mutant BRCA1 proteins may confer functions independent of the loss of wild-type BRCA1 through dominant negative inhibition of remaining wild-type BRCA1, or through novel interactions and pathways. These functions impact various cellular processes and have the potential to significantly influence cancer initiation and progression. In this review, we discuss the functional classifications of risk-associated BRCA1 mutations and their molecular, cellular and clinical impact for mutation carriers.

Precursor lesions of high-grade serous ovarian carcinoma: morphological and molecular characteristics

The lack of proven screening tools for early detection and the high mortality of ovarian serous carcinoma (OSC), particularly high grade, have focused attention on identifying putative precursor lesions with distinct morphological and molecular characteristics. The finding of occult invasive and intraepithelial fallopian tube carcinomas in prophylactically removed specimens from asymptomatic high-risk BRCA 1/2-mutation carriers supports the notion of an origin for OSC in the fallopian tube. The intraepithelial carcinomas have been referred to as serous intraepithelial carcinomas (STICs) but our own findings (unpublished data) and recent reports have drawn attention to a spectrum of changes that fall short of STICs that we have designated serous tubal intraepithelial lesions (STILs).

Genetic analysis of the early natural history of epithelial ovarian carcinoma

Background

The high mortality rate associated with epithelial ovarian carcinoma (EOC) reflects diagnosis commonly at an advanced stage, but improved early detection is hindered by uncertainty as to the histologic origin and early natural history of this malignancy.

Methodology/Principal Findings

Here we report combined molecular genetic and morphologic analyses of normal human ovarian tissues and early stage cancers, from both BRCA mutation carriers and the general population, indicating that EOCs frequently arise from dysplastic precursor lesions within epithelial inclusion cysts. In pathologically normal ovaries, molecular evidence of oncogenic stress was observed specifically within epithelial inclusion cysts. To further explore potential very early events in ovarian tumorigenesis, ovarian tissues from women not known to be at high risk for ovarian cancer were subjected to laser catapult microdissection and gene expression profiling. These studies revealed a quasi-neoplastic expression signature in benign ovarian cystic inclusion epithelium compared to surface epithelium, specifically with respect to genes affecting signal transduction, cell cycle control, and mitotic spindle formation. Consistent with this gene expression profile, a significantly higher cell proliferation index (increased cell proliferation and decreased apoptosis) was observed in histopathologically normal ovarian cystic compared to surface epithelium. Furthermore, aneuploidy was frequently identified in normal ovarian cystic epithelium but not in surface epithelium.

Conclusions/Significance

Together, these data indicate that EOC frequently arises in ovarian cystic inclusions, is preceded by an identifiable dysplastic precursor lesion, and that increased cell proliferation, decreased apoptosis, and aneuploidy are likely to represent very early aberrations in ovarian tumorigenesis.

Conditional inactivation of Brca1, p53 and Rb in mouse ovaries results in the development of leiomyosarcomas

Epithelial ovarian cancer (EOC) is thought to arise in part from the ovarian surface epithelium (OSE); however, the molecular events underlying this transformation are poorly understood. Germline mutations in the BRCA1 tumor suppressor gene result in a significantly increased risk of developing EOC and a large proportion of sporadic EOCs display some sort of BRCA1 dysfunction. To generate a model in which Brca1-mediated transformation can be studied, we previously inactivated Brca1 alone in murine OSE, which resulted in an increased accumulation of premalignant changes, but no tumor formation. In this study, we examined tumor formation in mice with conditionally expressed alleles of Brca1, p53 and Rb, alone or in combination. Intrabursal injection of adenovirus expressing Cre recombinase to inactivate p53 resulted in tumors in 100% of mice. Tumor progression was accelerated in mice with concomitant inactivation of Brca1 and p53, but not Rb and p53. Immunohistologic analyses classified the tumors as leiomyosarcomas that may be arising from the ovarian bursa. Brca1 inactivation in primary cultures of murine OSE cells led to a suppression of proliferation that could be rescued by concomitant inactivation of p53 and/or Rb. Brca1-deficient OSE cells displayed an increased sensitivity to the DNA damaging agent cisplatin, and this effect could be modulated by inactivation of p53 and/or Rb. These results indicate that Brca1 deficiency can accelerate tumor development and alter the sensitivity of OSE cells to chemotherapeutic agents. Intrabursal delivery of adenovirus intended to alter gene expression in the ovarian surface epithelium may, in some strains of mice, result in more rapid transformation of adjacent cells, resulting in leiomyosarcomas.

The mammalian ovary from genesis to revelation

Two major functions of the mammalian ovary are the production of germ cells (oocytes), which allow continuation of the species, and the generation of bioactive molecules, primarily steroids (mainly estrogens and progestins) and peptide growth factors, which are critical for ovarian function, regulation of the hypothalamic-pituitary-ovarian axis, and development of secondary sex characteristics. The female germline is created during embryogenesis when the precursors of primordial germ cells differentiate from somatic lineages of the embryo and take a unique route to reach the urogenital ridge. This undifferentiated gonad will differentiate along a female pathway, and the newly formed oocytes will proliferate and subsequently enter meiosis. At this point, the oocyte has two alternative fates: die, a common destiny of millions of oocytes, or be fertilized, a fate of at most approximately 100 oocytes, depending on the species. At every step from germline development and ovary formation to oogenesis and ovarian development and differentiation, there are coordinated interactions of hundreds of proteins and small RNAs. These studies have helped reproductive biologists to understand not only the normal functioning of the ovary but also the pathophysiology and genetics of diseases such as infertility and ovarian cancer. Over the last two decades, parallel progress has been made in the assisted reproductive technology clinic including better hormonal preparations, prenatal genetic testing, and optimal oocyte and embryo analysis and cryopreservation. Clearly, we have learned much about the mammalian ovary and manipulating its most important cargo, the oocyte, since the birth of Louise Brown over 30 yr ago.

Ovarian epithelial dysplasia and prophylactic oophorectomy for genetic risk

To make an accurate histopathological description of ovarian dysplasia in a population at genetic risk of ovarian cancer and devise an ovarian dysplasia score.

MATERIALS AND METHODS

In this retrospective cohort study, 90 patients who had undergone bilateral oophorectomy or ovarian cystectomy between 1992 and 2005 and whose ovaries were reported as normal were divided into two groups: Group A comprising prophylactic oophorectomies for genetic predisposition (N = 28), and Group B or control group, fertile and non-cancerous (N = 62). Eleven epithelial cytological and architectural features were defined. Ovaries were analysed and reviewed by four pathologists blinded to clinical data. An ovarian dysplasia score was devised to quantify extent of ovarian epithelial abnormalities. The degrees of ovarian epithelial abnormalities (dysplasia scores) were compared between the two groups.

RESULTS

Mean dysplasia score was significantly higher in Group A (prophylactic oophorectomies) than in Group B (control group) (9.67 vs. 4.19, P < 0.001). In Group A, we observed a gradation in the severity of the dysplastic lesions between (i) proven BRCA mutations and prophylactic oophorectomies without mutations (11.26 vs. 8.1), and (ii) according to age (10.27 after age 50 years vs. 8.6 before age 50 years, P = 0.2962).

CONCLUSION

These results suggest abnormalities in ovaries from high risk women. The ovarian dysplasia may be a pre-malignant, non-invasive histological lesion that could be an important step in early neoplasia.

Acquisition of a second mutation of the Tp53 alleles immediately precedes epithelial morphological transformation in ovarian tumorigenicity

OBJECTIVE

Tp53 mutation is frequent and associates with malignant, high-grade ovarian cancer. However, the details about the progression of Tp53 mutation from heterozygous to homozygous, and association between genotypes and morphological transformation are not clear. We further investigated the expression and mutation of Tp53 and associated markers such as p21 and HDM2 in ovarian cancer.

METHOD

Areas of contiguous ovarian surface epithelia linking morphological normal monolayer to multilayer neoplastic cells were analyzed for the correlation of Tp53 pathway alteration in relation to morphological transformation, by immunostaining and sequencing of Tp53 gene in cells from laser captured microdissection.

RESULTS

Consistent with previous reports, Tp53 staining is positive in 78% of the tumors. The staining of p21 is positive in about 12%, and HMD2 is positive in only 1% of the tumors. In 9 out of 10 cases of p21-positive tumors, p53 is also positive. In the majority of cases of epithelial histological transitions, overexpression of Tp53 correlates with morphological transformation: Tp53 is negative in monolayered cells and positive in neoplastic lesions. Morphological transformation also closely correlates with cell proliferation as indicated by Ki-67 staining and loss of p21 expression. We detected heterozygous mutation of Tp53 in the monolayers adjacent to neoplastic cells.

CONCLUSIONS

p21 expression is an indicator of a wild type Tp53 and lack of p21 in the presence of Tp53 expression predicts an inactivated Tp53. Tp53 inactivation immediately precedes morphological transformation of the ovarian surface epithelium in most cases, and the histological transitional epithelia containing a heterozygous Tp53 mutation are thus pre-neoplastic lesions. We propose that the loss of a second allele of Tp53 leading to the loss of p21 expression, and subsequent cell proliferation, compose a sequence of events that lead to morphological transformation and instigation of ovarian epithelial tumor development.

New insights into the pathogenesis of serous ovarian cancer and its clinical impact

There are only a handful of concepts concerning cancer and carcinogenesis that are currently beyond dispute. One such dogma is the adenoma-carcinoma sequence and that a multistep accumulation of genetic alterations is required for transformation from a benign to a neoplastic tissue. The inevitable derivative of this dogma is that every invasive carcinoma is in fact a missed intraepithelial tumor, and furthermore, a late evolutionary stage in the sequence of development from a precursor lesion. Until fairly recently, high-grade serous ovarian carcinoma seemed to be one of the only known deviants of these concepts. In this article, we discuss the emergence of the fallopian tube fimbria as a field of origin for high-grade serous carcinomas and present a binary model of ovarian cancer pathogenesis that takes into consideration prior epidemiologic, morphologic, and genetic data. With the rise of the fallopian tube secretory epithelial cell as a cell of origin for high-grade pelvic serous carcinomas, the need to develop tools and model systems to characterize the biology and physiology of this cell is recognized.

[Ovarian epithelial dysplasia: myth or reality? Review]

Ovarian epithelial dysplasia has been described in the ovarian surface epithelium by histologic, morphometric and nuclear profile studies. It could represent a potential precursor of ovarian malignancy in patients with genetic risk of ovarian cancer, although its natural history and progression to carcinoma are unpredictable. Diagnosis and identification of ovarian dysplasia would certainly be useful to understand the early steps of ovarian carcinogenesis. However, dysplasia in relation with ovulation induction seems to have a different pattern. We report dysplasia definitions and the current clinical management.

Activation of BTAK expression in primary ovarian surface epithelial cells of prophylactic ovaries

The ovarian epithelial cells carrying heterozygous BRCA1 or BRCA2 mutation (we called BRCA1/2 mutation) are known to predispose to the development of ovarian cancer; however, the molecular basis of such predisposition is largely unknown. We hypothesize that BTAK may be a potential target for heterozygous BRCA1/2 mutation. We sought to determine the relationship between the status of BRCA1/2 heterozygous mutation and BTAK expression in prophylactically removed ovaries as compared with normal ovaries and ovarian cancer controls. Western blot analysis of BTAK was performed in a primary cell culture carrying heterozygous BRCA1 mutation and three normal ovarian surface epithelial cell cultures. Immunohistochemical analysis of BTAK expression was also performed by image analysis in ovaries of 21 patients with known BRCA1/2 mutation or very strong family history of breast/ovarian cancer that underwent prophylactic oophorectomy, 38 normal ovaries from patients without any known mutation, and 194 ovarian carcinomas. The BTAK expression was significantly increased in primary culture carrying a heterozygous BRCA1 mutation as compared to those with no known BRCA1/2 mutation. Immunohistochemical staining of BTAK showed increased expression in ovarian epithelial cells carrying BRCA1/2 mutation or strong breast/ovarian family history compared with normal ovaries (P<0.001). Higher BTAK expression was found in ovarian cancer cells compared to ovaries without cancer but with known BRCA1/2 mutation or strong family history (P<0.001), and expression levels of BTAK and p53 were directly correlated (r=0.306; P<0.001). Increased expression of BTAK is directly correlated with mutation status of BRCA1/2 genes, suggesting that mutation in a single allele of either BRCA1 or 2 may be responsible for the activation of BTAK. This activation may be a key early genetic event in the development of hereditary ovarian cancer.

Evaluation of normal-sized ovaries associated with primary peritoneal serous carcinoma for possible precursors of ovarian serous carcinoma

OBJECTIVE

Three groups of "high-risk" ovaries have previously been studied for possible precursors of ovarian carcinoma: ovaries removed prophylactically from women at high risk, normal ovaries contralateral to a unilateral ovarian carcinoma, and normal ovarian tissue found adjacent to primary ovarian carcinomas. No data are available for a fourth high-risk group: normal-sized ovaries from women with primary peritoneal serous carcinoma.

METHODS

Grossly normal-sized ovaries from 26 patients with primary peritoneal serous carcinoma were compared to normal-sized ovaries from 75 controls. Controls were divided at the median age for age matching. Cortical inclusions, surface epithelial invaginations (clefts), surface papillary proliferation, and calcifications were examined.

RESULTS

Case versus control comparisons showed, respectively, inclusions in 92% and 68% of patients, clefts in 54% and 59%, and papillomatosis in 35% and 16%. For each profile of ovary on one section, cases versus controls, respectively, had a mean number of inclusions of 5.55 and 3.97, size of the largest inclusion of 1.28 and 1.27 mm, and depth of the deepest cleft of 1.04 and 0.9 mm. After controlling for age, correcting for multiple comparisons and using two-sided chi square, there were no significant differences between cases and controls in all the parameters measured. In comparing the two control groups, the only significant finding was that the young group displayed deeper clefts than the older group (2.06 versus 0.9 mm, respectively).

CONCLUSION

Grossly normal-sized ovaries from women with primary peritoneal serous carcinoma display no significant differences in inclusions, clefts, papillomatosis, and calcifications in comparison to age-matched controls.

The distal fallopian tube: a new model for pelvic serous carcinogenesis

PURPOSE OF REVIEW

Research over the past 50 years has yielded little concrete information on the source of pelvic serous cancer in women, creating a knowledge gap that has adversely influenced our ability to identify, remove or prevent the earliest stages of the most lethal form of ovarian cancer.

RECENT FINDINGS

The distal fallopian tube is emerging as an established source of many early serous carcinomas in women with BRCA mutations (BRCA+). Protocols examining the fimbrial (SEE-FIM) end have revealed a noninvasive but potentially lethal form of tubal carcinoma, designated tubal intraepithelial carcinoma. Tubal intraepithelial carcinoma is present in many women with presumed ovarian or peritoneal serous cancer. A candidate precursor to tubal intraepithelial carcinoma, entitled the 'p53 signature', suggests that molecular events associated with serous cancer (p53 mutations) may be detected in benign mucosa.

SUMMARY

A fully characterized precursor lesion is a first and necessary step to pelvic serous cancer prevention. The emerging data offer compelling evidence for a model of 'fimbrial-ovarian' serous neoplasia, and call attention to the distal fallopian tube as an important source for this disease, the study of which could clarify pathways to cancer in both organs and generate novel strategies for cancer prevention.

Macrophages in human fallopian tube and ovarian epithelial inclusion cysts

Epithelial inclusion cysts (EICs) are considered a preferential site for ovarian carcinogenesis. Local inflammation, associated to ovulatory wound repair and epithelial inflammatory conditions, facilitates EIC formation and involves activation of macrophages. The aim of this study was to analyse the presence and numbers of macrophages in the ovarian surface epithelium (OSE), in EICs, and in the fallopian tubes, as tubal metaplasia is a common finding in EICs. Immunohistochemical analysis of macrophages was performed in 25 fallopian tubes in different phases of the menstrual cycle, and in 30 ovaries showing EICs from cycling and postmenopausal women. In the fallopian tube, macrophages were abundant and underwent cyclic changes during the menstrual cycle, being particularly abundant within the epithelium at early and mid-luteal phases. Macrophages were not found in the normal OSE. However, OSE areas and EICs showing tubal metaplasia were invariably associated with infiltration by abundant macrophages. Macrophages were present among epithelial cells, infiltrating the cyst wall, as well as free in the cyst lumen. No significant differences existed between follicular and luteal phases of the cycle, or between cycling and postmenopausal women. This study has demonstrated that macrophages are associated with metaplastic EICs, and raises the possibility that these cells contribute to the particular microenvironment of EICs through secretion of cytokines and growth factors that may reach bioactive concentrations in the confined space of the EICs.

Epithelial–mesenchymal interconversions in normal ovarian surface epithelium and ovarian carcinomas: An exception to the norm

Cancer that arises from the ovarian surface epithelium (OSE) accounts for approximately 90% of human ovarian cancer, and is the fourth leading cause of cancer-related deaths among women in developed countries. The pathophysiology of epithelial ovarian cancer is still unclear because of the poor understanding of the complex nature of its development and the unusual mechanism(s) of disease progression. Recent studies have reported epithelial-mesenchymal transition (EMT) in cultured OSE and ovarian cancer cell lines in response to various stimuli, but our understanding of the importance of these observations for normal ovarian physiology and cancer progression is not well established. This review highlights the current literature on EMT-associated events in normal OSE and ovarian cancer cell lines, and discusses its implication for normal ovarian function as well as acquisition of neoplastic phenotypes. The pathological changes in OSE in response to EMT during neoplastic transformation and the contribution of hormones, growth factors, and cytokines that initiate and drive EMT to sustain normal ovarian function, as well as cancer development and progression are also discussed. Finally, emphasis is placed on the clinical implications of EMT and potential therapeutic opportunities that may arise from these observations have been proposed.

Age-dependent morphological alterations of human ovaries from populations with and without BRCA mutations

OBJECTIVE

From analysis of pre-cancer ovarian tissues obtained from prophylactic oophorectomies, several studies reported the increased ovarian morphological changes in high-risk ovaries, but whether these morphological changes are associated with BRCA1/BRCA2 genotypes or are cancer precursors is controversial. Here, we have investigated a recent collection of ovaries from prophylactic oophorectomies and control ovaries from surgeries due to other non-ovarian-related cancer or non-neoplastic diseases to determine if ovarian morphological changes relate to BRCA1/2 genotypes or reproductive history.

METHODS

We assembled a panel of archived ovarian tissues: 52 ovarian tissue blocks were from prophylactic oophorectomies of a high-risk (HR) population; 66 ovaries were from surgeries due to non-ovarian-related diseases, referred to as normal-risk (NR) group. The morphology of ovarian tissues was examined, and morphological changes including papillomatosis, invaginations, inclusion cysts, and epithelial stratification were assessed in a blinded fashion.

RESULTS

No statistically significant difference in frequency of these histolopathologic features was found between HR and NR groups. However, inclusion cysts and deep invaginations were found much more commonly in women age 45-54 of either HR or NR groups.

CONCLUSIONS

This study suggests that no significant increase in the presence of non-neoplastic ovarian morphological changes is associated with BRCA1/BRCA2 mutations. Rather, the frequency of these histological features, especially inclusion cysts, may associate with age or menopausal status. We propose that ovulatory and perimenopausal gonadotropin stimulation produces ovarian morphological changes, and these histological features may promote the transformation of genetically compromised epithelial cells in the development of ovarian cancer.

Conditional inactivation of Brca1 in the mouse ovarian surface epithelium results in an increase in preneoplastic changes

Epithelial ovarian cancer (EOC) is thought to arise from the ovarian surface epithelium (OSE); however, the molecular events underlying this transformation are poorly understood. Germline mutations in the BRCA1 tumor suppressor gene result in a significantly increased risk of developing EOC and a large proportion of sporadic EOCs display some sort of BRCA1 dysfunction. Using mice with conditional expression of Brca1, we inactivated Brca1 in the murine OSE and demonstrate that this inactivation results in the development of preneoplastic changes, such as hyperplasia, epithelial invaginations, and inclusion cysts, which arise earlier and are more numerous than in control ovaries. These changes resemble the premalignant lesions that have been reported in human prophylactic oophorectomy specimens from women with BRCA1 germline mutation. We also report that inactivation of Brca1 in primary cultures of murine OSE cells leads to a suppression of proliferation due to increased apoptosis that can be rescued by concomitant inactivation of p53. These observations, along with our finding that these cells display an increased sensitivity to the DNA-damaging agent cisplatin, indicate that loss of function of Brca1 in OSE cells impacts both cellular growth control and DNA-damage repair which results in altered cell behavior manifested as morphological changes in vivo that arise earlier and are more numerous than what can be attributed to ageing.

Incessant ovulation, inflammation and epithelial ovarian carcinogenesis: revisiting old hypotheses

Epithelial ovarian cancer (EOC) is often a lethal disease because in many cases early symptoms go undetected. Although research proceeds apace, as yet there are few reliable and specific biomarkers for the early stages of the disease. EOC is an umbrella label for a highly heterogeneous collection of cancers, which includes tumours of low malignant potential, serous cystadenomas, mucinous and clear cell carcinomas, all of which are likely to arise from a number of epithelial cell types and a variety of progenitor lesions. Many, but not all types of EOC are thought to arise from the cells lining ovarian inclusion cysts. In this review, we discuss the hypotheses that have driven our ideas on epithelial ovarian carcinogenesis and examine the morphological and genetic evidence for pathways to EOC. The emergence of laser-capture microdissection and expression profiling by microarray technologies offers the promise of defining these pathways more accurately, as well as providing us with the tools for earlier diagnosis.

Structural changes and cell properties of human ovarian surface epithelium in ovarian pathophysiology

The surface epithelial cells of the ovary, which are modified peritoneal cells, form a single, focally pseudostratified layer. The Müllerian ducts differentiate after invagination of the coelomic mesothelium over the gonadal ridges during the 6th week of embryonic life. On the basis of the embryologically putative Müllerian potential of this epithelium, endometriosis can be explained by coelomic metaplasia from the peritoneum, including ovarian surface epithelium. Some pelvic endometriosis specimens have shown that epithelial cells on the ovary or pelvis are serially changed to endometriotic gland cells. Immunohistochemistry as well as scanning electron microscopy also reinforce the light-microscopical findings. A three-dimensional culture system demonstrated that human ovarian surface epithelial cells exhibited a glandular-stromal structure when they were cocultured with endometrial stromal cells in an estrogen-rich environment. Ovarian carcinomas in the epithelial-stromal category are thought to arise from the surface epithelium and its inclusions. The ovarian surface epithelium is physiologically involved in follicular rupture, oocyte release, and the subsequent repair of follicle wall during reproductive age. Simultaneously, ovulation may cause a loss of integrity of the surface epithelium, followed by accumulation of multiple mutations. The cortical invagination, surface stromal proliferation, and Müllerian differentiation of these cells are likely not to be an early step in the cancer development. However, the inclusion cysts are closely related with carcinogenesis because they are significantly more common in ovaries contralateral to those containing epithelial cancers than in control ovaries. As an in vitro study, ovarian carcinoma cell lines were established from simian virus 40 large T antigen-transformed human surface epithelial cells of the ovary. Further investigations of these cell lines may lead to insights into the preneoplastic and early stages of carcinomas. To clarify the pathogenesis of endometriosis and epithelial ovarian cancer, specifically designed studies of ovarian surface epithelium are required.

Expression of cell cycle regulatory proteins in ovaries prophylactically removed from Jewish Ashkenazi BRCA1 and BRCA2 mutation carriers: Correlation with histopathology

OBJECTIVES

Prophylactic oophorectomy in Ashkenazi Jewish women with BRCA mutations represents a unique opportunity to search for premalignant changes in ovaries. Reports on the presence of dysplastic lesions in these ovaries are contradictory. Our aim was to study the expression of cell cycle regulatory proteins--p53, Skp2, p27, Ki67, Bcl2 and p16--in correlation with histopathological changes. p16(INK4A) was not studied before in prophylactically removed ovaries.

METHODS

Ninety-four ovaries from 50 Ashkenazi Jewish BRCA carriers were compared with 42 ovaries removed for reasons unrelated to cancer and with 16 ovarian carcinomas.

RESULTS

Three (6%) patients from the high-risk group had an occult carcinoma. A significant association was found between BRCA-positive expression and the presence of atypical changes in the superficial ovarian epithelium (P = 0.014) as well as the presence of epithelial cortical clefts (P = 0.042). Expression of p53 in cortical inclusions was significantly higher in the BRCA-positive cases than in the benign control group (P = 0.03). The high-risk and the benign control group did not differ significantly by the expression of p16, BCL2, Ki67, p27 and SKP2 (P > 0.05). However, both groups significantly differed from the carcinoma group (P < 0.0001). A significant positive correlation was found between the expression of Ki67, and the grade of atypia in the high-risk group (R = 0.3, P = 0.01) and in the benign control group (R = 0.5, P = 0.02).

CONCLUSIONS

BRCA mutation carriers had more atypical changes in the superficial epithelium (P = 0.014) and more epithelial cortical clefts (P = 0.042) compared to the benign control group. The histopathology changes were not supported by significantly altered expressions of the proteins used in our study. Additional molecular studies could contribute to the disclosure of precancerous ovarian lesions.