Tubal and ovarian pathways to pelvic epithelial cancer: a pathological perspective

Consensus based recommendations for the diagnosis of serous tubal intraepithelial carcinoma: an international Delphi study

AIM

Reliably diagnosing or safely excluding serous tubal intraepithelial carcinoma (STIC), a precursor lesion of tubo-ovarian high-grade serous carcinoma (HGSC), is crucial for individual patient care, for better understanding the oncogenesis of HGSC, and for safely investigating novel strategies to prevent tubo-ovarian carcinoma. To optimize STIC diagnosis and increase its reproducibility, we set up a three-round Delphi study.

METHODS AND RESULTS

In round 1, an international expert panel of 34 gynecologic pathologists, from 11 countries, was assembled to provide input regarding STIC diagnosis, which was used to develop a set of statements. In round 2, the panel rated their level of agreement with those statements on a 9-point Likert scale. In round 3, statements without previous consensus were rated again by the panel while anonymously disclosing the responses of the other panel members. Finally, each expert was asked to approve or disapprove the complete set of consensus statements. The panel indicated their level of agreement with 64 statements. A total of 27 statements (42%) reached consensus after three rounds. These statements reflect the entire diagnostic work-up for pathologists, regarding processing and macroscopy (three statements); microscopy (eight statements); immunohistochemistry (nine statements); interpretation and reporting (four statements); and miscellaneous (three statements). The final set of consensus statements was approved by 85%.

CONCLUSION

This study provides an overview of current clinical practice regarding STIC diagnosis amongst expert gynecopathologists. The experts' consensus statements form the basis for a set of recommendations, which may help towards more consistent STIC diagnosis.

Recommendations for diagnosing STIC: a systematic review and meta-analysis

Our understanding of the oncogenesis of high-grade serous cancer of the ovary and its precursor lesions, such as serous tubal intraepithelial carcinoma (STIC), has significantly increased over the last decades. Adequate and reproducible diagnosis of these precursor lesions is important. Diagnosing STIC can have prognostic consequences and is an absolute requirement for safely offering alternative risk reducing strategies, such as risk reducing salpingectomy with delayed oophorectomy. However, diagnosing STIC is a challenging task, possessing only moderate reproducibility. In this review and meta-analysis, we look at how pathologists come to a diagnosis of STIC. We performed a literature search identifying 39 studies on risk reducing salpingo-oophorectomy in women with a known BRCA1/2 PV, collectively reporting on 6833 patients. We found a pooled estimated proportion of STIC of 2.8% (95% CI, 2.0-3.7). We focused on reported grossing protocols, morphological criteria, level of pathologist training, and the use of immunohistochemistry. The most commonly mentioned morphological characteristics of STIC are (1) loss of cell polarity, (2) nuclear pleomorphism, (3) high nuclear to cytoplasmic ratio, (4) mitotic activity, (5) pseudostratification, and (6) prominent nucleoli. The difference in reported incidence of STIC between studies who totally embedded all specimens and those who did not was 3.2% (95% CI, 2.3-4.2) versus 1.7% (95% CI, 0.0-6.2) (p 0.24). We provide an overview of diagnostic features and present a framework for arriving at an adequate diagnosis, consisting of the use of the SEE-FIM grossing protocol, evaluation by a subspecialized gynecopathologist, rational use of immunohistochemical staining, and obtaining a second opinion from a colleague.

Weight Gain and the Risk of Ovarian Cancer in BRCA1 and BRCA2 Mutation Carriers

BACKGROUND

Weight gain and other anthropometric measures on the risk of ovarian cancer for women with BRCA mutations are not known. We conducted a prospective analysis of weight change since age 18, height, body mass index (BMI) at age 18, and current BMI and the risk of developing ovarian cancer among BRCA1 and BRCA2 mutation carriers.

METHODS

In this prospective cohort study, height, weight, and weight at age 18 were collected at study enrollment. Weight was updated biennially. Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence intervals (CI) for ovarian cancer.

RESULTS

This study followed 4,340 women prospectively. There were 121 incident cases of ovarian cancer. Weight gain of more than 20 kg since age 18 was associated with a 2-fold increased risk of ovarian cancer, compared with women who maintained a stable weight (HR, 2.00; 95% CI, 1.13-3.54; P = 0.02). Current BMI of 26.5 kg/m² or greater was associated with an increased risk of ovarian cancer in BRCA1 mutation carriers, compared with those with a BMI less than 20.8 kg/m² (Q4 vs. Q1 HR, 2.13; 95% CI, 1.04-4.36; P = 0.04). There were no significant associations between height or BMI at age 18 and risk of ovarian cancer.

CONCLUSIONS

Adult weight gain is a risk factor for ovarian cancer in women with a BRCA1 or BRCA2 mutation.

IMPACT

These findings emphasize the importance of maintaining a healthy body weight throughout adulthood in women at high risk for ovarian cancer.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

CBX7 binds the E-box to inhibit TWIST-1 function and inhibit tumorigenicity and metastatic potential

Deaths from ovarian cancer usually occur when patients succumb to overwhelmingly numerous and widespread micrometastasis. Whereas epithelial-mesenchymal transition is required for epithelial ovarian cancer cells to acquire metastatic potential, the cellular phenotype at secondary sites and the mechanisms required for the establishment of metastatic tumors are not fully determined. Using in vitro and in vivo models we show that secondary epithelial ovarian cancer cells (sEOC) do not fully reacquire the molecular signature of the primary epithelial ovarian cancer cells from which they are derived. Despite displaying an epithelial morphology, sEOC maintains a high expression of the mesenchymal effector, TWIST-1. TWIST-1 is however transcriptionally nonfunctional in these cells as it is precluded from binding its E-box by the PcG protein, CBX7. Deletion of CBX7 in sEOC was sufficient to reactivate TWIST-1-induced transcription, prompt mesenchymal transformation, and enhanced tumorigenicity in vivo. This regulation allows secondary tumors to achieve an epithelial morphology while conferring the advantage of prompt reversal to a mesenchymal phenotype upon perturbation of CBX7. We also describe a subclassification of ovarian tumors based on CBX7 and TWIST-1 expression, which predicts clinical outcomes and patient prognosis.

Prophylactic salpingectomy for the prevention of ovarian cancer: Who should we target?

Ovarian cancer is the most fatal gynecologic malignancy (50% 5-year survival) due to a typically advanced stage at diagnosis and a high rate of recurrence. Chemoprevention options are limited, and few interventions have been shown to reduce cancer risk or mortality. Emerging data support the model that fallopian tubes are the site of origin for a proportion of high-grade serous cancers. This implies that a subset of cancers may be prevented by removing the fallopian tubes while leaving the ovaries intact. Accordingly, there has been shift in clinical practice for average risk women; some now recommend removal of both the fallopian tubes only instead of tubal ligation for sterilization or at the time of benign gynecologic surgery. This has been termed opportunistic salpingectomy and represents a means of decreasing the burden of ovarian cancer by preventing cancers that arise in the fallopian tubes. There have been no detailed, prospective reports that have estimated ovarian cancer risk reduction with opportunistic salpingectomy, neither among women at baseline population risk nor among women at a high risk of developing the disease. The situation is complicated for women with a BRCA mutation-bilateral salpingo-oophorectomy is a proven means of risk reduction and salpingectomy alone is not the standard of care. Based on the existing data, salpingectomy alone should only be reserved for women with a lifetime risk of ovarian cancer of less than 5%.

Reproductive and Hormonal Factors and Risk of Ovarian Cancer by Tumor Dominance: Results from the Ovarian Cancer Cohort Consortium (OC3)

BACKGROUND

Laterality of epithelial ovarian tumors may reflect the underlying carcinogenic pathways and origins of tumor cells.

METHODS

We pooled data from 9 prospective studies participating in the Ovarian Cancer Cohort Consortium. Information on measures of tumor size or tumor dominance was extracted from surgical pathology reports or obtained through cancer registries. We defined dominant tumors as those restricted to one ovary or where the dimension of one ovary was at least twice as large as the other, and nondominant tumors as those with similar dimensions across the two ovaries or peritoneal tumors. Competing risks Cox models were used to examine whether associations with reproductive and hormonal risk factors differed by ovarian tumor dominance.

RESULTS

Of 1,058 ovarian cancer cases with tumor dominance information, 401 were left-dominant, 363 were right-dominant, and 294 were nondominant. Parity was more strongly inversely associated with risk of dominant than nondominant ovarian cancer (P heterogeneity = 0.004). Ever use of oral contraceptives (OC) was associated with lower risk of dominant tumors, but was not associated with nondominant tumors (P heterogeneity = 0.01). Higher body mass index was associated with higher risk of left-dominant tumors, but not significantly associated with risk of right-dominant or nondominant tumors (P heterogeneity = 0.08).

CONCLUSIONS

These data suggest that reproductive and hormonal risk factors appear to have a stronger impact on dominant tumors, which may have an ovarian or endometriosis origin.

IMPACT

Examining the associations of ovarian cancer risk factors by tumor dominance may help elucidate the mechanisms through which these factors influence ovarian cancer risk.

Tubal Origin of "Ovarian" Low-Grade Serous Carcinoma: A Gene Expression Profile Study

Objective

Ovarian low-grade serous carcinomas are thought to evolve in a stepwise fashion from ovarian epithelial inclusions, serous cystadenomas, and serous borderline tumors. Our previous study with clinicopathological approach showed that the majority ovarian epithelial inclusions are derived from the fallopian tubal epithelia rather than from ovarian surface epithelia. This study was designed to gain further insight into the cellular origin of ovarian low-grade serous carcinomas by differential gene expression profiling studies.

Methods

Gene expression profiles were studied in 43 samples including 11 ovarian low-grade serous carcinomas, 7 serous borderline tumors, 6 serous cystadenomas, 6 ovarian epithelial inclusions, 7 fallopian tubal epithelia, and 6 ovarian surface epithelia. Comprehensive analyses with hierarchical clustering, Rank-sum analysis and Pearson correlation tests were performed. Final validation was done on selected genes and corresponding proteins.

Results

The gene expression profiles distinguished ovarian low-grade serous carcinomas from ovarian surface epithelia, but not from fallopian tubal epithelia cells. Hierarchical clustering analysis showed ovarian serous tumors and ovarian epithelial inclusions were clustered closely in a branch, but separated from ovarian surface epithelia. The results were further validated by selected proteins of OVGP1, WT-1, and FOM3, which were highly expressed in the samples of the fallopian tube, ovarian epithelial inclusions, and ovarian serous tumors, but not in ovarian surface epithelia. The reverse was true for the protein expression patterns of ARX and FNC1.

Conclusions

This study provides evidence in a molecular level that ovarian low-grade serous carcinomas likely originate from the fallopian tube rather than from ovarian surface epithelia. Similar gene expression profiles among fallopian tube, ovarian epithelial inclusions, and serous tumors further support that ovarian low-grade serous carcinomas develop in a stepwise fashion. Such findings may have a significant implication for “ovarian” cancer-prevention strategies.

The biodiversity Composition of Microbiome in Ovarian Carcinoma Patients

Ovarian carcinoma is caused by multiple factors, but its etiology associated with microbes and infection is unknown. Using 16S rRNA high-throughput sequencing methods, the diversity and composition of the microbiota from ovarian cancer tissues (25 samples) and normal distal fallopian tube tissues (25 samples) were analyzed. High-throughput sequencing showed that the diversity and richness indexes were significantly decreased in ovarian cancer tissues compared to tissues from normal distal fallopian tubes. The ratio of the two phyla for Proteobacteria/Firmicutes was notably increased in ovarian cancer, which revealed that microbial composition change might be associated with the process of ovarian cancer development. In addition, transcriptome-sequencing (RNA-seq) analyses suggested that the transcriptional profiles were statistically different between ovarian carcinoma and normal distal fallopian tubes. Moreover, a set of genes including 84 different inflammation-associated or immune-associated genes, which had been named as the human antibacterial-response genes were also modulated expression. Therefore, we hypothesize that the microbial composition change, as a novel risk factor, may be involving the initiation and progression of ovarian cancer via influencing and regulating the local immune microenvironment of fallopian tubes except for regular pathways.

The biodiversity Composition of Microbiome in Ovarian Carcinoma Patients

Ovarian carcinoma is caused by multiple factors, but its etiology associated with microbes and infection is unknown. Using 16S rRNA high-throughput sequencing methods, the diversity and composition of the microbiota from ovarian cancer tissues (25 samples) and normal distal fallopian tube tissues (25 samples) were analyzed. High-throughput sequencing showed that the diversity and richness indexes were significantly decreased in ovarian cancer tissues compared to tissues from normal distal fallopian tubes. The ratio of the two phyla for Proteobacteria/Firmicutes was notably increased in ovarian cancer, which revealed that microbial composition change might be associated with the process of ovarian cancer development. In addition, transcriptome-sequencing (RNA-seq) analyses suggested that the transcriptional profiles were statistically different between ovarian carcinoma and normal distal fallopian tubes. Moreover, a set of genes including 84 different inflammation-associated or immune-associated genes, which had been named as the human antibacterial-response genes were also modulated expression. Therefore, we hypothesize that the microbial composition change, as a novel risk factor, may be involving the initiation and progression of ovarian cancer via influencing and regulating the local immune microenvironment of fallopian tubes except for regular pathways.

The biodiversity Composition of Microbiome in Ovarian Carcinoma Patients

Ovarian carcinoma is caused by multiple factors, but its etiology associated with microbes and infection is unknown. Using 16S rRNA high-throughput sequencing methods, the diversity and composition of the microbiota from ovarian cancer tissues (25 samples) and normal distal fallopian tube tissues (25 samples) were analyzed. High-throughput sequencing showed that the diversity and richness indexes were significantly decreased in ovarian cancer tissues compared to tissues from normal distal fallopian tubes. The ratio of the two phyla for Proteobacteria/Firmicutes was notably increased in ovarian cancer, which revealed that microbial composition change might be associated with the process of ovarian cancer development. In addition, transcriptome-sequencing (RNA-seq) analyses suggested that the transcriptional profiles were statistically different between ovarian carcinoma and normal distal fallopian tubes. Moreover, a set of genes including 84 different inflammation-associated or immune-associated genes, which had been named as the human antibacterial-response genes were also modulated expression. Therefore, we hypothesize that the microbial composition change, as a novel risk factor, may be involving the initiation and progression of ovarian cancer via influencing and regulating the local immune microenvironment of fallopian tubes except for regular pathways.

Cell Origins of High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer, also known as high-grade serous carcinoma (HGSC), is the most common and deadliest type of ovarian cancer. HGSC appears to arise from the ovary, fallopian tube, or peritoneum. As most HGSC cases present with widespread peritoneal metastases, it is often not clear where HGSC truly originates. Traditionally, the ovarian surface epithelium (OSE) was long believed to be the origin of HGSC. Since the late 1990s, the fallopian tube epithelium has emerged as a potential primary origin of HGSC. Particularly, serous tubal intraepithelial carcinoma (STIC), a noninvasive tumor lesion formed preferentially in the distal fallopian tube epithelium, was proposed as a precursor for HGSC. It was hypothesized that STIC lesions would progress, over time, to malignant and metastatic HGSC, arising from the fallopian tube or after implanting on the ovary or peritoneum. Many clinical studies and several mouse models support the fallopian tube STIC origin of HGSC. Current evidence indicates that STIC may serve as a precursor for HGSC in high-risk women carrying germline BRCA1 or 2 mutations. Yet not all STIC lesions appear to progress to clinical HGSCs, nor would all HGSCs arise from STIC lesions, even in high-risk women. Moreover, the clinical importance of STIC remains less clear in women in the general population, in which 85–90% of all HGSCs arise. Recently, increasing attention has been brought to the possibility that many potential precursor or premalignant lesions, though composed of microscopically—and genetically—cancerous cells, do not advance to malignant tumors or lethal malignancies. Hence, rigorous causal evidence would be crucial to establish that STIC is a bona fide premalignant lesion for metastatic HGSC. While not all STICs may transform into malignant tumors, these lesions are clearly associated with increased risk for HGSC. Identification of the molecular characteristics of STICs that predict their malignant potential and clinical behavior would bolster the clinical importance of STIC. Also, as STIC lesions alone cannot account for all HGSCs, other potential cellular origins of HGSC need to be investigated. The fallopian tube stroma in mice, for instance, has been shown to be capable of giving rise to metastatic HGSC, which faithfully recapitulates the clinical behavior and molecular aspect of human HGSC. Elucidating the precise cell(s) of origin of HGSC will be critical for improving the early detection and prevention of ovarian cancer, ultimately reducing ovarian cancer mortality.

Adopting a Uniform Approach to Site Assignment in Tubo-Ovarian High-Grade Serous Carcinoma: The Time has Come

There is currently sufficient evidence that nonuterine high-grade serous carcinoma (HGSC) originates in the fallopian tube in the majority of cases, but this is not uniformly reflected in our diagnostic terminology. This is because there remains wide variation in awareness and acceptance of this evidence, which conflicts with traditional views on origin. Accurate disease classification is fundamental to routine clinical practice and research, particularly at a time when exciting new approaches to therapy, early detection, and prevention are appearing on the horizon. We feel the time has come to minimize individual and institutional variations in practice, and agree on an evidence-based approach to uniform terminology and primary site assignment. In this paper we put forward a proposal for a unified approach based on published research evidence and discuss the reasons why it is vital to agree on a uniform protocol. We propose the term "Tubo-ovarian HGSC" in preference to "pelvic" or "Müllerian," as it accurately reflects the origin of this disease in the vast majority of cases, and is unambiguous, distinguishing it clearly from uterine serous carcinoma and ovarian low-grade serous carcinomas. A detailed protocol for primary site assignment is presented for different scenarios, which is easy to follow and has been developed with a view to promoting a uniform approach worldwide.

Lifestyle and Reproductive Factors and Ovarian Cancer Risk by p53 and MAPK Expression

Background: One model of ovarian cancer development model divides tumors into two types. Type I tumors are characterized by KRAS and BRAF mutations, which can activate mitogen-activated protein kinase (MAPK). Type II tumors are characterized by tubal precursor lesions with p53 mutations. We evaluated the association between lifestyle and reproductive factors and risk of ovarian cancer defined by p53 and MAPK expression.Methods: Epithelial ovarian cancer cases (n = 274) and controls (n = 1,907) were identified from the Nurses' Health Study and Nurses' Health Study II prospective cohorts, and the population-based New England Case-Control study. Reproductive and lifestyle exposures were assessed by questionnaire/interview. We performed immunohistochemical assays for p53 and MAPK expression. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using polytomous logistic regression.Results: Parity was associated with a decreased risk of p53 wild-type tumors (OR = 0.31; 95% CI, 0.18-0.55), but not p53-mutant tumors (OR = 0.92; 95% CI, 0.54-1.59)(P_{heterogeneity} < 0.01). Family history of breast or ovarian cancer was associated with risk of MAPK-negative (OR = 2.06; 95% CI, 1.39-3.06), but not MAPK-positive tumors (OR = 0.74; 95% CI, 0.43-1.27; P_{heterogeneity}< 0.01). In cross-classified analyses, family history of breast or ovarian cancer was most strongly associated with p53-mutant/MAPK-negative tumors (OR = 2.33; 95% CI, 1.44-3.75). Differences by MAPK expression were also observed for estrogen plus progesterone hormone therapy use (P_{heterogeneity} = 0.03).Conclusions: These findings provide evidence that parity, family history, and estrogen plus progesterone hormone therapy use may be differentially associated with tumor subtypes defined by p53 and MAPK expression.Impact: In future studies, other immunohistochemical markers or gene expression profiles that more clearly define these subtypes should be considered. Cancer Epidemiol Biomarkers Prev; 27(1); 96-102. ©2017 AACR.

CREB5 promotes tumor cell invasion and correlates with poor prognosis in epithelial ovarian cancer

CAMP responsive element binding protein 5 (CREB5) has crucial roles in regulating cell growth, proliferation, differentiation and cell cycle regulation. CREB5 has been identified to be overexpressed in several types of human cancer. However, the expression characteristics of CREB5 in epithelial ovarian cancer remains unknown, and its potential clinical prognostic significance has not yet been elucidated. In the present study, quantitative polymerase chain reaction (qPCR) and western blot analysis were performed to detect CREB5 mRNA and protein expression levels in 10 fresh tissue and cell lines epithelial ovarian cancer. Furthermore, CREB5 expression was analyzed using immunohistochemical analysis in 125 clinicopathologically characterized ovarian cancers: Stage I+II (n=31), stage III (n=70), stage IV (n=24). The patient survival rate was evaluated using Kaplan-Meier analysis. CREB5 was significantly overexpressed at both the mRNA and protein levels in epithelial ovarian cancer cells. There was a significant positive correlation between high CREB5 expression and increasing the International Federation of Gynecology and Obstetrics (FIGO) stage and pelvic lymph node metastasis (P<0.05). Patients with high CREB5 expression had a shorter overall survival, whereas patients with low CREB5 expression had longer survival. In addition, patients with high CREB5 expression had shorter relapse-free survival whereas patients with low CREB5 expression had longer relapse-free survival. Univariate logistic regression analysis and stepwise multivariate analysis all revealed that the FIGO stage and high CREB5 expression were significant risk factors for epithelial ovarian cancer (P<0.001), which suggested that CREB5 upregulation may be associated with a poor prognosis; therefore, it may be an independent prognostic indicator of epithelial ovarian cancer and may serve as a tumor-aggressive gene.

Sequential molecular changes and dynamic oxidative stress in high-grade serous ovarian carcinogenesis

The mechanism of high-grade serous ovarian cancer (HGSC) development remains elusive. This review outlines recent advances in the understanding of sequential molecular changes associated with the development of HGSC, as well as describes oxidative stress-induced genomic instability and carcinogenesis. This article reviews the English language literature between 2005 and 2017. Clinicopathological features analysis provides a sequential progression of fallopian tubal epithelium to precursor lesions to type 2 HGSC. HGSC may develop over a long time after incessant ovulation and repeated retrograde menstruation via stepwise accumulation of genetic alterations, including PAX2, ALDH1A1, STMN1, EZH2 and CCNE1, which confer positive selection of cells with growth advantages through acquiring driver mutations such as BRCA1/2, p53 or PTEN/PIK3CA. Haemoglobin and iron-induced oxidative stress leads to the emergence of genetic alterations in fallopian tubal epithelium via increased DNA damage and impaired DNA repair. Serous tubal intraepithelial carcinoma (STIC), the likely precursor of HGSC, may be susceptible to DNA double-strand breaks, exhibit DNA replication stress and increase genomic instability. The induction of genomic instability is considered to be a driving mechanism of reactive oxygen species (ROS)-induced carcinogenesis. HGSC exemplifies the view of stepwise cancer development. We describe how genetic alterations emerge during HGSC carcinogenesis related to oxidative stress.

[Grading of gynecological tumors : Current aspects]

Histopathological assessment of the tumor grade and cell type is central to the management and prognosis of various gynecological malignancies. Conventional grading systems for squamous carcinomas and adenocarcinomas of the vulva, vagina and cervix are poorly defined. For endometrioid tumors of the female genital tract as well as for mucinous endometrial, ovarian and seromucinous ovarian carcinomas, the 3‑tiered FIGO grading system is recommended. For uterine neuroendocrine tumors the grading system of the gastrointestinal counterparts has been adopted. Uterine leiomyosarcomas are not graded. Endometrial stromal sarcomas are divided into low and high grades, based on cellular morphology, immunohistochemical and molecular findings. A chemotherapy response score was established for chemotherapeutically treated high-grade serous pelvic cancer. For non-epithelial ovarian malignancies, only Sertoli-Leydig cell tumors and immature teratomas are graded. At this time molecular profiling has no impact on the grading of tumors of the female genital tract.

The conceptual advances of carcinogenic sequence model in high-grade serous ovarian cancer

The present review focuses on the current status of molecular pathology in high-grade serous cancer (HGSC) and preneoplastic conditions. This article reviews the English-language literature on HGSC, precursor, fallopian tubal epithelium, secretory cells, ciliated cells, secretory cell expansion, secretory cell outgrowth (SCOUT), p53 signature, serous tubal intraepithelial carcinoma (STIC), DNA damage and immunohistochemistry in an effort to identify the precursor-carcinoma sequence in HGSC. The majority of HGSC originates from the fimbriated end of the fallopian tube secretory epithelial cells, while the small part of this disease may develop from ovarian cortical inclusion cyst (CIC). A series of morphological changes from normal fallopian epithelium to preneoplastic to neoplastic lesions were concomitant with the multistep accumulation of molecular and genetic alterations. Recent studies provide a stepwise progression of fallopian tubal epithelium to precursor lesions to carcinoma, with the aid of a 'secretory cell-SCE-SCOUT-p53 signature-STIC-HGSC sequence' model. Immunohistochemical markers, including p53, STMN1, EZH2, CCNE1, Ki67 and γ-H2AX, were gradually increased during the SCOUT-p53 signature-STIC-HGSC sequence. Conversely, PAX2 expression was decreased during the early phase of SCOUT development. Potential genes and proteins are involved in the evolutionary trajectory of the precursor-cancer lineage model. In the present review we examined detailed aspects of the molecular changes involved in malignant transformation from fallopian tube epithelium to HGSC. A precursor condition originating in 'field cancerization' may gain a growth advantage, leading to HGSC.

Tubal Cytology of the Fallopian Tube as a Promising Tool for Ovarian Cancer Early Detection

Currently, it is widely accepted that the vast majority of ovarian high-grade serous carcinoma (HGSC) originate from the fallopian tube. However, due to the lack of markers or tools for the ovarian cancer identification, the early detection of HGSC remains challenging. Direct sampling of the fallopian tube can enhance sensitivity for detection of neoplastic cells when the tumor is not grossly visible. We developed a procedure to collect fallopian tube cells directly from freshly received surgical specimens, which has shown excellent correlation with histological findings. This approach lays a foundation for the future utility of minimally invasive laparoscopic screening in high-risk patient populations.

Obesity and Ovarian Cancer

Ovarian cancer is the most fatal gynecologic cancer and is an important source of cancer-related mortality, particularly in developed countries. Despite substantial research examining adiposity (primarily adult body mass index [BMI]), the overall evidence suggests only a weak positive association between adiposity and risk of ovarian cancer, with stronger associations observed for population-based case-control studies compared to prospective studies. Ovarian cancer is not one disease and emerging data suggest that higher BMI may only be associated with risk of certain histologic subtypes, including low-grade serous and invasive mucinous tumors. Interestingly, some larger studies and meta-analyses have reported a stronger relationship with premenopausal ovarian cancers, which are more likely to be of these subtypes. Relatively few studies have conducted detailed examinations of other adiposity-related factors such as measures of abdominal adiposity, early-life body size and weight change. While the underlying mechanisms that may relate adiposity to risk are unclear, increased inflammatory biomarkers have been associated with risk and hormonal factors, including androgen levels, may be important for the development of mucinous tumors. Future research should leverage the large sample sizes of consortia to evaluate associations by key tumor characteristics as well as consider patterns of weight change over the life course with both ovarian cancer risk and survival.

Cytologic studies of the fallopian tube in patients undergoing salpingo-oophorectomy

BACKGROUND

Mounting evidence suggests the fallopian tube as the origin for ovarian high grade serous carcinoma (HGSC). We attempted to identify the tubal cytological features that allow us to distinguish malignant from benign conditions.

METHODS

Tubal specimens (n = 56) were collected from patients who underwent bilateral salpingo-oophorectomy (BSO) due to various clinical indications. A standard procedure to collect fallopian tube brushings from freshly received surgical specimens was developed. Cytological diagnoses were classified into three categories: benign, atypical, and suspicious for malignancy/malignant. Cytological variables of individual cells and epithelia were subjected to statistical analysis. The fallopian tube histology was used as diagnostic reference for confirmation of cytology diagnosis.

RESULTS

Among the 56 fallopian tube specimens, 2 (3.7 %) showed inadequate cellularity preventing further evaluation, 11 (20.4 %) were diagnosed as malignant or suspicious of malignancy, 7 were atypical, and 36 were benign. The presence of three dimensional clusters (p < 0.0001, Fisher's Exact Test), or prominent nucleoli (p = 0.0252, Fisher Exact test) was highly correlated with the diagnosis of malignancy. The suspicious malignant/malignant cytological diagnosis was also highly correlated with presence of HGSC with or without serous tubal intraepithelial carcinoma (STIC).

CONCLUSIONS

Tubal cytology may be useful for ovarian cancer screening and early detection.

Ovarian Cancer: The Fallopian Tube as the Site of Origin and Opportunities for Prevention

High-grade serous carcinoma (HGSC) is the most common and aggressive histotype of epithelial ovarian cancer (EOC), and it is the predominant histotype associated with hereditary breast and ovarian cancer syndrome (HBOC). Mutations in BRCA1 and BRCA2 are responsible for most of the known causes of HBOC, while mutations in mismatch repair genes and several genes of moderate penetrance are responsible for the remaining known hereditary risk. Women with a history of familial ovarian cancer or with known germline mutations in highly penetrant genes are offered the option of risk-reducing surgery that involves the removal of the ovaries and fallopian tubes (salpingo-oophorectomy). Growing evidence now supports the fallopian tube epithelia as an etiological site for the development of HGSC and consequently, salpingectomy alone is emerging as a prophylactic option. This review discusses the site of origin of EOC, the rationale for risk-reducing salpingectomy in the high-risk population, and opportunities for salpingectomy in the low-risk population.

Reproductive factors and epithelial ovarian cancer survival in the EPIC cohort study

BACKGROUND

Reproductive factors influence the risk of developing epithelial ovarian cancer (EOC), but little is known about their association with survival. We tested whether prediagnostic reproductive factors influenced EOC-specific survival among 1025 invasive EOC cases identified in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which included 521,330 total participants (approximately 370,000 women) aged 25-70 years at recruitment from 1992 to 2000.

METHODS

Information on reproductive characteristics was collected at recruitment. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), and multivariable models were adjusted for age and year of diagnosis, body mass index, tumour stage, smoking status and stratified by study centre.

RESULTS

After a mean follow-up of 3.6 years (±3.2 s.d.) following EOC diagnosis, 511 (49.9%) of the 1025 women died from EOC. We observed a suggestive survival advantage in menopausal hormone therapy (MHT) users (ever vs never use, HR=0.80, 95% CI=0.62-1.03) and a significant survival benefit in long-term MHT users (⩾5 years use vs never use, HR=0.70, 95% CI=0.50-0.99, P(trend)=0.04). We observed similar results for MHT use when restricting to serous cases. Other reproductive factors, including parity, breastfeeding, oral contraceptive use and age at menarche or menopause, were not associated with EOC-specific mortality risk.

CONCLUSIONS

Further studies are warranted to investigate the possible improvement in EOC survival in MHT users.

The role of reproductive hormones in epithelial ovarian carcinogenesis

Epithelial ovarian cancer comprises ∼85% of all ovarian cancer cases. Despite acceptance regarding the influence of reproductive hormones on ovarian cancer risk and considerable advances in the understanding of epithelial ovarian carcinogenesis on a molecular level, complete understanding of the biologic processes underlying malignant transformation of ovarian surface epithelium is lacking. Various hypotheses have been proposed over the past several decades to explain the etiology of the disease. The role of reproductive hormones in epithelial ovarian carcinogenesis remains a key topic of research. Primary questions in the field of ovarian cancer biology center on its developmental cell of origin, the positive and negative effects of each class of hormones on ovarian cancer initiation and progression, and the role of the immune system in the ovarian cancer microenvironment. The development of the female reproductive tract is dictated by the hormonal milieu during embryogenesis. Intensive research efforts have revealed that ovarian cancer is a heterogenous disease that may develop from multiple extra-ovarian tissues, including both Müllerian (fallopian tubes, endometrium) and non-Müllerian structures (gastrointestinal tissue), contributing to its heterogeneity and distinct histologic subtypes. The mechanism underlying ovarian localization, however, remains unclear. Here, we discuss the role of reproductive hormones in influencing the immune system and tipping the balance against or in favor of developing ovarian cancer. We comment on animal models that are critical for experimentally validating existing hypotheses in key areas of endocrine research and useful for preclinical drug development. Finally, we address emerging therapeutic trends directed against ovarian cancer.

Histo-genomic stratification reveals the frequent amplification/overexpression of CCNE1 and BRD4 genes in non-BRCAness high grade ovarian carcinoma

The treatment of epithelial ovarian cancer (EOC) is narrowly focused despite the heterogeneity of this disease in which outcomes remain poor. To stratify EOC patients for targeted therapy, we developed an approach integrating expression and genomic analyses including the BRCAness status. Gene expression and genomic profiling were used to identify genes recurrently (>5%) amplified and overexpressed in 105 EOC. The LST (Large-scale State Transition) genomic signature of BRCAness was applied to define molecular subgroups of EOC. Amplified/overexpressed genes clustered mainly in 3q, 8q, 19p and 19q. These changes were generally found mutually exclusive. In the 85 patients for which the genomic signature could be determined, genomic BRCAness was found in 52 cases (61.1%) and non-BRCAness in 33 (38.8%). A striking mutual exclusivity was observed between BRCAness and amplification/overexpression data. Whereas 3q and 8q alterations were preferentially observed in BRCAness EOC, most alterations on chromosome 19 were in non-BRCAness cases. CCNE1 (19q12) and BRD4 (19p13.1) amplification/overexpression was found in 19/33 (57.5%) of non-BRCAness cases. Such disequilibrium was also found in the TCGA EOC data set used for validation. Potential target genes are frequently amplified/overexpressed in non-BRCAness EOC. We report that BRD4, already identified as a target in several tumor models, is a new potential target in high grade non-BRCAness ovarian carcinoma.

Loss of LKB1 and p53 synergizes to alter fallopian tube epithelial phenotype and high-grade serous tumorigenesis

Liver kinase B1 (LKB1) is a tumor suppressor ubiquitously expressed serine/threonine protein kinase involved in energy metabolism and cellular polarity. In microarray experiments that compared normal tubal epithelium with high-grade serous carcinoma (HGSC), we observed a decrease in LKB1 mRNA expression in HGSC. In this study, we demonstrate that loss of cytoplasmic and nuclear LKB1 protein expression is frequently observed in tubal cancer precursor lesions as well as in both sporadic and hereditary HGSCs compared with other ovarian cancer histotypes. Bi-allelic genomic loss of LKB1 in HGSC did not account for the majority of cases with a decrease in protein expression. In vitro, shLKB1-fallopian tube epithelial (FTE) cells underwent premature cellular arrest and in ex vivo FTE culture, LKB1 loss and p53 mutant synergized to disrupt apical to basal polarity and decrease the number of ciliated cells. Overexpression of cyclin E1 allowed for bypass of LKB1-induced cellular arrest, and increased both proliferation and anchorage-independent growth of transformed FTE cells. These data suggest that LKB1 loss early in ovarian serous tumorigenesis has an integral role in tumor promotion by disrupting apical to basal polarity in the presence of mutated p53 in fallopian tube cells.

Ovarian cancer survival by tumor dominance, a surrogate for site of origin

OBJECTIVES

Recent studies suggest that a proportion of ovarian tumors may actually originate in the distal fallopian tube. The objective of this study was to examine the relationship between dominance (a surrogate for site of origin) and survival, following a diagnosis of epithelial ovarian cancer.

METHODS

We classified 1,386 tumors as dominant (putatively originating in the ovary) and non-dominant (putatively originating in the fallopian tube), using parameters obtained from pathology reports. Dominant tumors were restricted to one ovary or one involved ovary that exceeded the other in dimension by at least twofold, while non-dominant tumors were identified as having a greater likelihood of a tubal origin if the disease was equally distributed across the ovaries. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) associated with dominance.

RESULTS

Non-dominant tumors were more likely to be serous, stage III/IV, and be associated with a BRCA1/2 mutation, increasing parity and use of estrogen hormone replacement therapy (p ≤ 0.01). In contrast, 46 and 26% of the dominant tumors were serous and endometrioid, respectively, with a more even distribution of stage (p < 0.0001). Women with a non-dominant tumor had an increased risk of death compared to women with a dominant tumor (multivariate HR 1.28; 95% CI 1.02-1.60). Findings were similar in our analysis restricted to serous only subtypes (HR 1.28; 95% CI 1.01-1.63).

CONCLUSION

These preliminary findings suggest significantly worse survival among women diagnosed with a tumor putatively arising from fallopian tube.

Primary sources of pelvic serous cancer in patients with endometrial intraepithelial carcinoma

Serous endometrial intraepithelial carcinoma is often associated with extrauterine disease. It is currently unclear where does the extrauterine disease come from. This study addressed this issue. A total of 135 samples from 21 serous endometrial intraepithelial carcinoma patients were studied. Cellular lineage relationships between intrauterine and extrauterine serous carcinomas were determined by TP53-mutation analysis and correlated to the clinicopathologic features. There were three conditions contributing the extrauterine disease: metastasis from serous endometrial intraepithelial carcinoma (n=10) showed identical TP53 mutation between intrauterine lesions and extrauterine disease, cases of adnexal origin (n=5) had discordant TP53 mutations, and the mixed cellular origin cases (n=6) with both identical and discordant mutation status. Patients with extrauterine disease from serous endometrial intraepithelial carcinoma metastasis typically had small tumor masses (<2 cm) in extrauterine sites and without finding of serous tubal intraepithelial carcinoma, while extrauterine disease with adnexal or tubal origin commonly had larger tumor masses in extrauterine sites including ovary and omentum and serous tubal intraepithelial carcinoma. The majority of extrauterine diseases associated with serous endometrial intraepithelial carcinoma are metastasized from the endometrium. Serous endometrial intraepithelial carcinoma is frequently associated with serous cancers of adnexal or tubal origin, indicating that endometrial and adnexal or tubal serous cancers may share similar etiologies. TP53-mutation analysis provides a strong linkage for cellular lineage analysis. Tumor size in extrauterine disease and presence of serous tubal intraepithelial carcinoma or not are useful clinicopathologic features to determine primary cancer site, which helps in clinical management.

Factors influencing ovulation and the risk of ovarian cancer in BRCA1 and BRCA2 mutation carriers

The role of the lifetime number of ovulatory cycles has not been evaluated in the context of BRCA-associated ovarian cancer. Thus, we conducted a matched case-control study to evaluate the relationship between the cumulative number of ovulatory cycles (and contributing components) and risk of developing ovarian cancer in BRCA mutation carriers (1,329 cases and 5,267 controls). Information regarding reproductive and hormonal factors was collected from a routinely administered questionnaire. Conditional logistic regression was used to evaluate all associations. We observed a 45% reduction in the risk of developing ovarian cancer among women in the lowest vs. highest quartile of ovulatory cycles (OR = 0.55; 95% CI 0.41-0.75, p = 0.0001). Breastfeeding for more than 12 months was associated with a 38% (95% CI 0.48-0.79) and 50% (95% CI 0.29-0.84) reduction in risk among BRCA1 and BRCA2 mutation carriers, respectively. For oral contraceptive use, maximum benefit was seen with five or more years of use among BRCA1 mutation carriers (OR = 0.50; 95% CI 0.40-0.63) and three or more years for BRCA2 mutation carriers (OR = 0.42; 95% CI 0.22-0.83). Increasing parity was associated with a significant inverse trend among BRCA1 (OR = 0.87; 95% CI 0.79-0.96; p-trend = 0.005) but not BRCA2 mutation carriers (OR 0.98; 95% CI 0.81-1.19; p-trend = 0.85). A later age at menopause was associated with an increased risk in women with a BRCA1 mutation (OR trend = 1.18; 95% CI 1.03-1.35; p = 0.02). These findings support an important role of breastfeeding and oral contraceptive use for the primary prevention of ovarian cancer among women carrying BRCA mutations.

Recent concepts of ovarian carcinogenesis: type I and type II

Type I ovarian tumors, where precursor lesions in the ovary have clearly been described, include endometrioid, clear cell, mucinous, low grade serous, and transitional cell carcinomas, while type II tumors, where such lesions have not been described clearly and tumors may develop de novo from the tubal and/or ovarian surface epithelium, comprise high grade serous carcinomas, undifferentiated carcinomas, and carcinosarcomas. The carcinogenesis of endometrioid and clear cell carcinoma (CCC) arising from endometriotic cysts is significantly influenced by the free iron concentration, which is associated with cancer development through the induction of persistent oxidative stress. A subset of mucinous carcinomas develop in association with ovarian teratomas; however, the majority of these tumors do not harbor any teratomatous component. Other theories of their origin include mucinous metaplasia of surface epithelial inclusions, endometriosis, and Brenner tumors. Low grade serous carcinomas are thought to evolve in a stepwise fashion from benign serous cystadenoma to a serous borderline tumor (SBT). With regard to high grade serous carcinoma, the serous tubal intraepithelial carcinomas (STICs) of the junction of the fallopian tube epithelium with the mesothelium of the tubal serosa, termed the “tubal peritoneal junction” (TPJ), undergo malignant transformation due to their location, and metastasize to the nearby ovary and surrounding pelvic peritoneum. Other theories of their origin include the ovarian hilum cells.

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.

BRCA and Early Events in the Development of Serous Ovarian Cancer

Women who have an inherited mutation in the BRCA1 or BRCA2 genes have a substantial increased lifetime risk of developing epithelial ovarian cancer (EOC), and epidemiological factors related to parity, ovulation, and hormone regulation have a dramatic effect on the risk in both BRCA mutation carriers and non-carriers. The most common and most aggressive histotype of EOC, high-grade serous carcinoma (HGSC), is also the histotype associated with germline BRCA mutations. In recent years, evidence has emerged indicating that the likely tissue of origin of HGSC is the fallopian tube. We have reviewed, what is known about the fallopian tube in BRCA mutation carriers at both the transcriptional and translational aspect of their biology. We propose that changes of the transcriptome in BRCA heterozygotes reflect an altered response to the ovulatory stresses from the microenvironment, which may include the post-ovulation inflammatory response and altered reproductive hormone physiology.

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.

FOXO3a loss is a frequent early event in high-grade pelvic serous carcinogenesis

Serous ovarian carcinoma is the most lethal gynecological malignancy in Western countries. The molecular events that underlie the development of the disease have been elusive for many years. The recent identification of the fallopian tube secretory epithelial cells (FTSECs) as the cell-of-origin for most cases of this disease has led to studies aimed at elucidating new candidate therapeutic pathways through profiling of normal FTSECs and serous carcinomas. Here, we describe the results of transcriptional profiles that identify the loss of the tumor suppressive transcription factor FOXO3a in a vast majority of high grade serous ovarian carcinomas (HGSOCs). We show that FOXO3a loss is a hallmark of the earliest stages of serous carcinogenesis and occurs both at the DNA, RNA and protein levels. We describe several mechanisms responsible for FOXO3a inactivity, including chromosomal deletion (chromosome 6q21), upregulation of miRNA-182 and destabilization by activated PI3K and MEK. The identification of pathways involved in the pathogenesis of ovarian cancer can advance the management of this disease from being dependant on surgery and cytotoxic chemotherapy alone to the era of targeted therapy. Our data strongly suggest FOXO3a as a possible target for clinical intervention.

Matching maternal isodisomy in mucinous carcinomas and associated ovarian teratomas provides evidence of germ cell derivation for some mucinous ovarian tumors

The tissue derivation of mucinous ovarian carcinoma remains a mystery; however, rare tumors are associated with mature teratoma. Two decades ago, studies of chromosomal heteromorphisms and DNA polymorphisms proved that ovarian teratomas arise during female gametogenesis. We sought to exploit the relationship between mucinous carcinoma and associated teratoma to provide molecular evidence for tissue of origin. Seventeen cases of mucinous ovarian carcinoma were studied, 6 of which had associated mature teratoma. DNA was extracted from the mucinous carcinoma, teratoma, and normal dissected tissue from formalin-fixed, paraffin-embedded sections. Twelve polymorphic microsatellite markers were used to allelotype each sample. Alleles from the teratomas and carcinomas were scored as homozygous (1 allele present in the tumor when normal tissue was heterozygous), heterozygous (2 alleles present matching normal tissue), or noninformative (normal tissue was homozygous). Of the 6 carcinoma/teratoma pairs, 2 showed complete matching homozygosity for informative markers (isodisomy), whereas 2 showed matching heterozygosity. One case did not have the corresponding teratoma available for comparison but demonstrated complete homozygosity and was presumed to be isodisomic. The remaining case had a teratoma homozygous for 7 of 10 informative markers, whereas the matching carcinoma was homozygous for only 2 of these markers. Carcinomas without associated teratoma demonstrated variable zygosity. Microsatellite polymorphism analysis demonstrates that mucinous ovarian carcinomas usually clonally match associated teratomas when present and often show evidence of complete isodisomy, indicating that at least some mucinous carcinomas arise from female gametes and thus are of germ cell origin. The zygosity patterns in mucinous carcinomas without teratoma suggest that these tumors may arise through a different mechanism.

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.

Ovarian cancer risk factors by tumor dominance, a surrogate for cell of origin

Differentiating ovarian tumors based on developmental pathway may further enhance our understanding of the disease. Traditionally, ovarian cancers were thought to arise from the ovarian surface epithelium; however, recent evidence suggests that some tumors originate in the fallopian tube. We classified cases in a population-based case-control study (New England Case-Control [NECC] Study) and two cohort studies (Nurses' Health Study [NHS]/Nurses' Health Study II [NHSII]) by tumor dominance, a proxy for tissue of origin. Dominant tumors (likely ovarian origin) are restricted to one ovary or are at least twice as large on one ovary compared to the other. Ovarian cancer risk factors were evaluated in relation to dominant and nondominant tumors (likely tubal origin) using polytomous logistic regression (NECC) or competing risks Cox models (NHS/NHSII). Results were combined using random-effects meta-analyses. Among 1,771 invasive epithelial ovarian cancer cases, we observed 1,089 tumors with a dominant mass and 682 with no dominant mass. Dominant tumors were more likely to be mucinous, endometrioid or clear cell, whereas nondominant tumors were more likely to be serous. Tubal ligation, two or more births, endometriosis and age were more strongly associated with dominant tumors (rate ratio [RR] = 0.60, 0.83, 1.58 and 1.37, respectively) than nondominant tumors (RR = 1.03, 0.93, 0.84 and 1.14, respectively; p-difference = 0.0001, 0.01, 0.0003 and 0.01, respectively). These data suggest that risk factors for tumors putatively arising from ovarian versus fallopian tube sites may differ; in particular, reproductive factors may be more important for ovarian-derived tumors. As this is the first study to evaluate ovarian cancer risk factors by tumor dominance, these results need to be validated by other studies.

Reproductive characteristics in relation to ovarian cancer risk by histologic pathways

STUDY QUESTION

Do reproductive risk factor associations differ across subgroups of invasive epithelial ovarian cancer (EOC) defined by the dualistic model (type I/II) or a histologic pathway-based classification?

SUMMARY ANSWER

Associations with parity, history of endometriosis, tubal ligation and hysterectomy were found to differ in the context of the type I/II and the histologic pathways classification of ovarian cancer.

WHAT IS KNOWN ALREADY

Shared molecular alterations and candidate precursor lesions suggest that tumor histology and grade may be used to classify ovarian tumors into likely etiologic pathways.

DESIGN

This case-control study included 1571 women diagnosed with invasive EOC and 2100 population-based controls that were enrolled from 1992 to 2008. Reproductive risk factors as well as other putative risk factors for ovarian cancer were assessed through in-person interviews.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible cases were diagnosed with incident ovarian cancer, were aged 18 and above and resided in eastern Massachusetts or New Hampshire, USA. Controls were identified through random digit dialing, drivers' license and town resident lists and were frequency matched with the cases based on age and study center.

MAIN RESULTS AND THE ROLE OF CHANCE

We used polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for type I/II EOC or using a pathway-based grouping of histologic subtypes. In multivariate analyses, we observed that having a history of endometriosis (OR = 1.92, 95% CI: 1.36-2.71) increased the risk for a type I tumor. Factors that were strongly inversely associated with risk for a type I tumor included parity (≥ 3 versus 0 children, OR = 0.15, 95% CI: 0.11-0.21), having a previous tubal ligation (OR = 0.40, 95% CI: 0.26-0.60) and more weakly hysterectomy (OR = 0.71, 95% CI: 0.45-1.13). In analyses of histologic pathways, parity (≥ 3 versus 0 children, OR = 0.13, 95% CI: 0.10-0.18) and having a previous tubal ligation (OR = 0.41, 95% CI: 0.28-0.60) or hysterectomy (OR = 0.54, 95% CI: 0.34-0.86) were inversely associated with risk of endometrioid/clear cell tumors. Having a history of endometriosis strongly increased the risk for endometrioid/clear cell tumors (OR = 2.41, 95% CI: 1.78-3.26). We did not observe significant differences in the risk associations across these tumor classifications for age at menarche, menstrual cycle length or infertility.

LIMITATIONS, REASONS FOR CAUTION

A potential limitation of this study is that dividing the cases into subgroups may limit the power of these analyses, particularly for the less common tumor types. Since cases were enrolled after their diagnosis, it is possible that the most aggressive cases were not included in the study.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides insights about the role of reproductive factors in relation to risk of pathway-based subgroups of ovarian cancer that with further confirmation may assist with the development of improved strategies for the prevention of these different tumor types.

STUDY FUNDING/COMPETING INTEREST(S)

This research is funded by grants from the National Cancer Institute, the Department of Defense Ovarian Cancer Research Program and the Ovarian Cancer Research Fund. The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Proliferation in the normal FTE is a hallmark of the follicular phase, not BRCA mutation status

PURPOSE

Women who have inherited germline mutations of BRCA1/BRCA2 are at increased risk of developing high-grade serous carcinoma, and many of these cancers arise in the distal fimbriated end of the fallopian tube. We have previously shown that the fallopian tube epithelia of BRCA1 mutation carriers (FTE-BRCA) have altered signaling pathways compared to nonmutation carriers. In this study, we sought to determine whether these differences result in a proliferative advantage to the epithelia in this high-risk patient population and to investigate whether the postovulation environment of the FTE-BRCA compared to FTE from nonmutation carriers experiences a differential abundance of immune cells.

METHOD

Immunohistochemistry for Ki67, CD3, CD8, CD20, and CD68 was performed on histologically normal tubal epithelium (ampulla, n = 83), fimbria (n = 18) with known ovarian cycle status and germline mutation status and for Ki67 on fimbrial epithelium from women (n = 144) with and without BRCA1 or BRCA2 mutations who underwent risk-reducing salpingo-oophorectomy (RRSO). Serous tubal intraepithelial carcinomas (STIC) with concomitant cancer (n = 15) were also analyzed for presence of immune infiltrates. All slides were digitized and analyzed using automated image analysis software.

RESULTS

There was no significant difference in the proliferative index in histologically normal FTE between BRCA1/BRCA2 and non-BRCA, in 144 fimbriae and 83 ampullae. The FTE-BRCA1 epithelia did not exhibit a differential presence of lymphocytes or macrophages, however more macrophages were present in the luteal phase compared to the follicular phase epithelia. In STICs macrophages were more abundant than lymphocytes with an incremental increase noted with disease progression.

CONCLUSIONS

BRCA1/2 mutation carriers exhibited no significant increase in proliferation in the fallopian tube epithelial cells either in the ampulla or fimbriated ends of the tube. Rather, a significant proliferative increase was defined in the cases determined to be in the follicular, or proliferative, preovulatory phase of the ovarian cycle. Finally, we also show an incremental increase in leukocytes invading the STICs and HGSC, implicating a possible role of the leukocytes early in the progression or inhibition of tumor formation, which is independent of ovarian cycle status.

Detection of PAX8 and p53 is beneficial in recognizing metastatic carcinomas in pelvic washings, especially in cases with suspicious cytology

OBJECTIVE

The aim of this study is to evaluate the detection of paired box gene 8 (PAX8) and p53 with immunohistochemistry in pelvic washing cell block sections.

METHODS

A total of 92 cases were used in this study, which were assigned to three groups according to the cytopathology files. The first group with positive cytology including endometrial and ovarian carcinomas comprised 32 cases. The second group with suspicious cytology for endometrial or ovarian carcinomas consisted of 29 cases. The third group with negative cytology (regarded as mesothelial cells) included 31 cases. The pelvic washing cell blocks underwent immunohistochemistry to detect PAX8 and p53 expression.

RESULTS

Immunoreactivity for PAX8 was found in 75% (24/32) of the cases in the group with positive cytology, in 6.9% (2/29) of the cases with suspicious cytology, and in none of the 31 cases with negative cytology (sensitivity: 75%; specificity: 100%; p<0.05). p53 expression was detected in 37.5% (12/32) of the cases in the first group, in 3.4% (1/29) of the cases in the second group, and in none of the cases in the third group (sensitivity: 37.5%; specificity: 100%; p<0.05). Moreover, the combined expression of PAX8 and p53 showed the same result as the single expression of p53 in the three groups.

CONCLUSION

The detection of PAX8 and p53 is beneficial in recognizing metastatic carcinomas in pelvic washings, especially in cases with suspicious cytology, which additionally supports the Müllerian origin of these carcinomas.

Molecular mechanisms linking endometriosis under oxidative stress with ovarian tumorigenesis and therapeutic modalities

Inflammation plays a role in the pathogenesis of endometriosis. Endometriosis-associated ovarian carcinogenesis might be promoted through oxidative stress-induced increased genomic instability, aberrant methylation, and aberrant chromatin remodeling, as well as mutations of tumor suppressor genes. Aberrant expression of ARID1A, PIK3CA, and NF-kB genes has been recognized as the major target genes involved in oxidative stress-induced carcinogenesis. HNF-1beta appears to play a key role in anti-oxidative defense mechanisms. We discuss the pathophysiologic roles of oxidative stress as somatic mutations as well as highly specific agents that effectively modulate these targets.

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."