Pathology of stage I versus stage III ovarian carcinoma with implications for pathogenesis and screening

Current strategies for early epithelial ovarian cancer detection using miRNA as a potential tool

Ovarian cancer is one of the most aggressive and significant malignant tumor forms in the female reproductive system. It is the leading cause of death among gynecological cancers owing to its metastasis. Since its preliminary disease symptoms are lacking, it is imperative to develop early diagnostic biomarkers to aid in treatment optimization and personalization. In this vein, microRNAs, which are short sequence non-coding molecules, displayed great potential as highly specific and sensitive biomarker. miRNAs have been extensively advocated and proven to serve an instrumental part in the clinical management of cancer, especially ovarian cancer, by promoting the cancer cell progression, invasion, delayed apoptosis, epithelial-mesenchymal transition, metastasis of cancer cells, chemosensitivity and resistance and disease therapy. Here, we cover our present comprehension of the most up-to-date microRNA-based approaches to detect ovarian cancer, as well as current diagnostic and treatment strategies, the role of microRNAs as oncogenes or tumor suppressor genes, and their significance in ovarian cancer progression, prognosis, and therapy.

Diagnostic value of circN4BP2L2 in type I and type II epithelial ovarian cancer

BACKGROUND

CircN4BP2L2 was previously identified to be significantly decreased in epithelial ovarian cancer (EOC) and was associated with disease progression. The aim of this study was to evaluate the diagnostic value of plasma circN4BP2L2 using the unifying model of type I and type II EOC.

METHODS

A total of 540 plasma samples were obtained from 180 EOC patients, 180 benign ovarian cyst patients, and 180 healthy volunteers. CircN4BP2L2 was assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cancer antigen 125 (CA125) and human epididymis protein 4 (HE4) were assessed using enzyme-linked immunosorbent assay (ELISA). Receiver operating curve (ROC), the area under the curve (AUC), sensitivity and specificity were estimated.

RESULTS

Low level of circN4BP2L2 was associated with advanced tumor stage (p < 0.01) in type I EOC. Decreased circN4BP2L2 was associated with lymph node metastasis (LNM) (p = 0.04) in type II EOC. The expression level of circN4BP2L2 in type I was similar to that in type II. CircN4BP2L2 could significantly separate type I or type II from benign or normal cohort (p < 0.01). Early-stage type I or type II EOC vs. benign or normal cohort could also be distinguished by circN4BP2L2 (p < 0.01).

CONCLUSION

CircN4BP2L2 might serve as a promising diagnostic biomarker for both type I and type II EOC. The diagnostic safety for circN4BP2L2 in early-stage type I or type II EOC is also acceptable. Further large-scale well-designed studies are warranted to investigate whether circN4BP2L2 is specific for all histologic subgroups.

Modeling High-Grade Serous Ovarian Carcinoma Using a Combination of In Vivo Fallopian Tube Electroporation and CRISPR-Cas9-Mediated Genome Editing

Ovarian cancer is the most lethal gynecologic cancer to date. High-grade serous ovarian carcinoma (HGSOC) accounts for most ovarian cancer cases, and it is most frequently diagnosed at advanced stages. Here, we developed a novel strategy to generate somatic ovarian cancer mouse models using a combination of in vivo electroporation and CRISPR-Cas9-mediated genome editing. Mutation of tumor suppressor genes associated with HGSOC in two different combinations (Brca1, Tp53, Pten with and without Lkb1) resulted in successfully generation of HGSOC, albeit with different latencies and pathophysiology. Implementing Cre lineage tracing in this system enabled visualization of peritoneal micrometastases in an immune-competent environment. In addition, these models displayed copy number alterations and phenotypes similar to human HGSOC. Because this strategy is flexible in selecting mutation combinations and targeting areas, it could prove highly useful for generating mouse models to advance the understanding and treatment of ovarian cancer. SIGNIFICANCE: This study unveils a new strategy to generate genetic mouse models of ovarian cancer with high flexibility in selecting mutation combinations and targeting areas.

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.

Screening for ovarian cancer: imaging challenges and opportunities for improvement

The United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) recently reported a reduction in the average overall mortality among ovarian cancer patients screened with an annual sequential, multimodal strategy that tracked biomarker CA125 over time, where increasing serum CA125 levels prompted ultrasound. However, multiple cases were documented wherein serum CA125 levels were rising, but ultrasound screens were normal, thus delaying surgical intervention. A significant factor which could contribute to false negatives is that many aggressive ovarian cancers are believed to arise from epithelial cells on the fimbriae of the fallopian tubes, which are not readily imaged. Moreover, because only a fraction of metastatic tumors may reach a sonographically-detectable size before they metastasize, annual screening with ultrasound may fail to detect a large fraction of early-stage ovarian cancers. The ability to detect ovarian carcinomas before they metastasize is critical and future efforts towards improving screening should focus on identifying unique features specific to aggressive, early-stage tumors, as well as improving imaging sensitivity to allow for detection of tubal lesions. Implementation of a three-stage multimodal screening strategy in which a third modality is employed in cases where the first-line blood-based assay is positive and the second-line ultrasound exam is negative may also prove fruitful in detecting early-stage cases missed by ultrasound.

Ovarian Cancer, the Revised FIGO Staging System, and the Role of Imaging

OBJECTIVE

It is now recognized that ovarian cancer includes a heterogeneous group of malignant epithelial tumors originating from the ovaries, fallopian tubes, or peritoneum. This development has prompted the International Federation of Gynecology and Obstetrics (FIGO) to issue a revised staging system that can provide prognostic information and guidance on personalized management of ovarian cancer.

CONCLUSION

We review the epidemiology of ovarian cancer, the new FIGO staging system, and the role of imaging in the assessment, staging, and follow-up of ovarian cancer.

Revised FIGO staging system for cancer of the ovary, fallopian tube, and peritoneum: important implications for radiologists

Ovarian cancer is the seventh most common cancer diagnosis among women worldwide. The International Federation of Gynecology and Obstetrics recently significantly revised staging criteria for cancer of the ovary. The latest revision was based on the concept that high-grade serous tubal intraepithelial carcinoma (STIC) may be the origin of some high-grade serous carcinomas of the ovary and peritoneum. Therefore, staging criteria for the ovary, fallopian tube, and peritoneum have been unified. Understanding this background and other important revised points are essential for radiologists concerned with imaging diagnosis in gynecologic oncology. Through this review, we introduce the STIC theory and show examples of diseases in accordance with the new staging criteria based on magnetic resonance imaging (MRI) and computed tomography (CT) results.

The ovary is an alternative site of origin for high-grade serous ovarian cancer in mice

Although named "ovarian cancer," it has been unclear whether the cancer actually arises from the ovary, especially for high-grade serous carcinoma (HGSC), also known as high-grade serous ovarian cancer, the most common and deadliest ovarian cancer. In addition, the tumor suppressor p53 is the most frequently mutated gene in HGSC. However, whether mutated p53 can cause HGSC remains unknown. In this study, we bred a p53 mutation, p53(R172H), into conditional Dicer-Pten double-knockout (DKO) mice, a mouse model duplicating human HGSC, to generate triple-mutant (TKO) mice. Like DKO mice, these TKO mice develop metastatic HGSCs originating from the fallopian tube. Unlike DKO mice, however, even after fallopian tubes are removed in TKO mice, ovaries alone can develop metastatic HGSCs, indicating that a p53 mutation can drive HGSC arising from the ovary. To confirm this, we generated p53(R172H)-Pten double-mutant mice, one of the genetic control lines for TKO mice. As anticipated, these double-mutant mice also develop metastatic HGSCs from the ovary, verifying the HGSC-forming ability of ovaries with a p53 mutation. Our study therefore shows that ovaries harboring a p53 mutation, as well as fallopian tubes, can be a distinct tissue source of high-grade serous ovarian cancer in mice.

Evaluation of human epididymis protein 4 (HE4) and Risk of Ovarian Malignancy Algorithm (ROMA) as diagnostic tools of type I and type II epithelial ovarian cancer in Japanese women

Human epididymis protein 4 (HE4) levels and the Risk of Ovarian Malignancy Algorithm (ROMA) have recently been shown to improve the sensitivity and specificity of epithelial ovarian cancer (EOC) diagnosis. We evaluated HE4 levels and ROMA as diagnostic tools of type I and type II EOC in Japanese women. Women who had a pelvic mass on imaging and were scheduled to undergo surgery were enrolled as ovarian mass patients. Serum levels of carbohydrate antigen 125 (CA125) and HE4 were tested in 319 women (131 benign, 19 borderline, 75 malignant, and 94 healthy controls). CA125, HE4, and ROMA were evaluated for sensitivity and by receiver operating characteristics (ROC) in type I and type II EOC. The results showed that, at 75% specificity, the sensitivity of CA125 and HE4 for type II was 92.1% for both markers and for type I was 51.5% and 78.8%, respectively. The sensitivities of ROMA (type I, 84.8% and type II, 97.4%) were better than those of CA125 and HE4. CA125, HE4, and ROMA were all highly accurate markers for type II. For type I, HE4 and ROMA showed better sensitivity than CA125. ROMA displayed the best diagnostic power for type I and type II including for the early stage of type I. In conclusion, HE4, CA125, and ROMA are valuable markers for type II EOC diagnosis. HE4 and ROMA analyses may improve differentiation between type I EOC and a benign mass. Measurement of combined HE4 and CA125 levels provides a more accurate method for EOC diagnosis.

Diagnostic performance of the biomarkers HE4 and CA125 in type I and type II epithelial ovarian cancer

OBJECTIVE

To evaluate the diagnostic performance of HE4 and CA125 in patients presenting with suspicious malignant ovarian cysts. We especially wanted to investigate the levels of HE4 and CA125 with regard to the gene and histology-unifying model of type I and type II epithelial ovarian cancer (EOC).

METHODS

Plasma from 373 women presenting with a suspicious malignant ovarian cyst was collected prior to surgery. Histology, grade, and stage were determined according to FIGO-classification. HE4 and CA125 were analyzed using ELISA, and the markers were evaluated for significance separately and in combination. Receiver operating curves, the area under the curve, sensitivity and specificity were estimated.

RESULTS

The combination of HE4 and CA125 resulted in the best diagnostic power in comparing benign tumors to EOC (ROC AUC 0.93, sensitivity 94.4% at 75% specificity) for type II. Diagnostic power in type I (ROC AUC 0.79, sensitivity 61.9% at 75% specificity) was less impressive. In particular, mucinous benign vs. malignant tumors could not significantly be separated by the dual marker combination. Impressively high ROC AUC 0.99 was found for the late stage type II EOC with 100% sensitivity at 75% specificity.

CONCLUSIONS

HE4 and CA125 have a good ability to diagnose the more aggressive type II tumors but a poor diagnostic ability when patients are presenting with slow-growing type I in the early stage. Our results support the hypothesis that EOC should be looked upon as several different diseases, and that we lack biomarkers for sub-groups of EOC.

Survival rates for international federation of gynecology and obstetrics stage III ovarian carcinoma by cell type: a study of 262 unselected patients with uniform pathologic review

OBJECTIVE

Published data are conflicting on the influence of cell type on prognosis in ovarian cancer. The recent separation of low-grade serous carcinoma as a distinctive cell type of ovarian cancer with an indolent behavior, in retrospect, suggests that survival in studies that have not separated this group may be inaccurate.

METHODS

An unselected series of 262 International Federation of Gynecology and Obstetrics stage III ovarian carcinomas was studied. Diagnostic classification of each tumor was made with particular attention to recent refinements in cell-type classification. Survival curves were constructed according to Kaplan-Meier and compared with the log-rank test.

RESULTS

The 5-year survival for 207 high-grade serous carcinomas was 40%, as compared with 71% for 18 patients with low-grade serous carcinoma (P = 0.0113). Low-grade serous carcinoma was significantly more likely to be optimally debulked (P = 0.0039) and significantly less likely to be substage IIIC (P < 0.0001). The survival for carcinosarcoma was significantly inferior to all serous carcinomas (P = 0.0322). The significance of this latter comparison was lost when carcinosarcomas were compared with only high-grade serous carcinoma (P > 0.05).

CONCLUSIONS

Low-grade serous carcinoma has a significantly better prognosis than high-grade serous carcinoma and also differs with regard to substage distribution and proportion of patients optimally debulked. Because of its excellent prognosis, failure to separate low-grade serous carcinomas, notwithstanding its infrequent occurrence, can change the results of survival analyses that do not make this separation.

The role of liver-directed surgery in patients with hepatic metastasis from a gynecologic primary carcinoma

BACKGROUND

The management of patients with liver metastasis from a gynecologic carcinoma remains controversial, as there is currently little data available. We sought to determine the safety and efficacy of liver-directed surgery for hepatic metastasis from gynecologic primaries.

METHODS

Between 1990 and 2010, 87 patients with biopsy-proven liver metastasis from a gynecologic carcinoma were identified from an institutional hepatobiliary database. Fifty-two (60%) patients who underwent hepatic surgery for their liver disease and 35 (40%) patients who underwent biopsy only were matched for age, primary tumor characteristics, and hepatic tumor burden. Clinicopathologic, operative, and outcome data were collected and analyzed.

RESULTS

Of the 87 patients, 30 (34%) presented with synchronous metastasis. The majority of patients had multiple hepatic tumors (63%), with a median size of the largest lesion being 2.5 cm. Of those patients who underwent liver surgery (n=52), most underwent a minor hepatic resection (n=44; 85%), while 29 (56%) patients underwent concurrent lymphadenectomy and 45 (87%) patients underwent simultaneous peritoneal debulking. Postoperative morbidity and mortality were 37% and 0%, respectively. Median survival from time of diagnosis was 53 months for patients who underwent liver-directed surgery compared with 21 months for patients who underwent biopsy alone (n=35) (p=0.01). Among those patients who underwent liver-directed surgery, 5-year survival following hepatic resection was 41%.

CONCLUSIONS

Hepatic surgery for liver metastasis from gynecologic cancer can be performed safely. Liver surgery may be associated with prolonged survival in a subset of patients with hepatic metastasis from gynecologic primaries and therefore should be considered in carefully selected patients.

ACR appropriateness criteria© ovarian cancer screening

The majority of women with ovarian cancer have advanced stage disease at the time of diagnosis and a poor 5 year survival rate. Hence, screening has been investigated in the hopes of improving survival by diagnosing ovarian cancer at an earlier stage. Most screening methods thus far have included ultrasound and/or serum tumor markers. However, low prevalence of the disease, high false positive rate of current screening methods, and the probable rapid growth of most ovarian carcinomas from no defined precursor lesion, all contribute to difficulty in screening for ovarian cancer. While screening may be able to detect ovarian cancer at an earlier stage, adequate data is presently lacking on whether screening improves survival. The results of ongoing large clinical trials will be available in a few years and should provide critical information regarding the usefulness of screening. Pending results of those large clinical trials, screening is not currently recommended for women at average risk for ovarian cancer. Screening is most likely to be performed in women with an increased familial risk of ovarian cancer, but patients should be aware that even with this risk factor, there is currently insufficient evidence to know if screening is effective. New screening methods, including new or multiple serum markers and proteomics, are also being investigated.

Differences in tumor type in low-stage versus high-stage ovarian carcinomas

Although there are recognized differences in the type of ovarian carcinomas between those tumors diagnosed at low versus high stage, there is a lack of data on stage distribution of ovarian carcinomas diagnosed according to the current histopathologic criteria from large population-based cohorts. We reviewed full slide sets of 1009 cases of 2555 patients diagnosed with ovarian carcinoma that were referred to the British Columbia Cancer Agency over a 16-year period (1984 to 2000). On the basis of the reviewed cases we extrapolated the distribution of tumor type in low-stage (I/II) and high-stage (III/IV) tumors. We then compared the frequencies with those seen in a large hospital practice. The overall frequency of tumor types was as follows: high-grade serous-68.1%, clear-cell-12.2%, endometrioid-11.3%, mucinous-3.4%, low-grade serous-3.4%, rare types-1.6%. High-grade serous carcinomas accounted for 35.5% of stage I/II tumors and 87.7% of stage III/IV tumors. In contrast, clear-cell (26.2% vs. 4.5%), endometrioid (26.6% vs. 2.5%), and mucinous (7.5% vs. 1.2%) carcinomas were relatively more common among the low-stage versus high-stage tumors. This distribution was found to be very similar in 410 consecutive cases from the Washington Hospital Center. The distribution of ovarian carcinoma types differs significantly in patients with low-stage versus high-stage ovarian carcinoma when contemporary diagnostic criteria are used, with consistent results seen in 2 independent case series. These findings reflect important biological differences in the behavior of the major tumor types, with important clinical implications.

Qualitative age interactions between low-grade and high-grade serous ovarian carcinomas

PURPOSE

Ovarian epithelial carcinomas, including the predominant serous ovarian carcinoma (SOC) type, are heterogeneous malignancies. Even though invasive SOCs of low and high grade can be distinguished by morphology and molecular or immunohistochemical profiles, age-specific risks relevant to their separate carcinogenic pathways and clinical features have not been fully explored.

METHODS

In search of further clues to the etiology/pathogenesis of low-grade and high-grade SOCs, we analyzed incidence rate patterns. Case and age-adjusted population data were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for years 1990 through 2005. Descriptive epidemiology for n = 19,899 cases was supplemented with age-period-cohort models fitted by grade.

RESULTS

SOC age-adjusted incidence rate ratios (IRR) of high to low grade (IRR(H/L)) were <1.0 before age 40, and >1.0 thereafter. Accordingly, SOC age-specific incidence rates were also greater for low grade before age 40 years, and then greater for high grade. The reversals of IRR(H/L), with crossings of the age-specific incidence rate near age 40 years occurred irrespective of early or late SOC stage. These results were reproducible and reliable in age-period-cohort models that were adjusted for period and cohort effects (P approximately 0 for age interactions by grade).

CONCLUSIONS

Robust qualitative age interactions between low-grade and high-grade SOC showed that grade is an age-specific effect modifier in these malignancies. With increasing research interest in identifying the genomic determinants of SOC risk, therapeutic response, and outcome, future analytic studies and clinical trials should be powered to account for age-dependent grade interactions.

How close is the bench to the bedside? Metabolic profiling in cancer research

Metabolic profiling using mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) is integral to the rapidly expanding field of metabolomics, which is making progress in toxicology, plant science and various diseases, including cancer. In the area of oncology and metabolic phenotyping, researchers have probed the known changes in malignant cellular pathways using new experimental techniques to gain more insights, and others are exploiting these same cellular pathways for therapeutic drug targets and for novel cancer biomarkers, with the ultimate goal of translation to the clinic. Here, we discuss the challenges and opportunities in metabolic phenotyping for discovering novel cancer biomarkers, and we assess the clinical applicability of MS and NMR.

The impact of comorbidity and stage on ovarian cancer mortality: a nationwide Danish cohort study

Background

The incidence of ovarian cancer increases sharply with age, and many elderly patients have coexisting diseases. If patients with comorbidities are diagnosed with advanced stages, this would explain the poor survival observed among ovarian cancer patients with severe comorbidity. Our aims were to examine the prevalence of comorbidity according to stage of cancer at diagnosis, to estimate the impact of comorbidity on survival, and to examine whether the impact of comorbidity on survival varies by stage.

Methods

From the Danish Cancer Registry we identified 5,213 patients (> 15 years old) with ovarian cancer diagnosed from 1995 to 2003. We obtained information on comorbidities from the Danish National Hospital Discharge Registry. Vital status was determined through linkage to the Civil Registration System. We estimated the prevalence of comorbidity by stage and computed absolute survival and relative mortality rate ratios (MRRs) by comorbidity level (Charlson Index score 0, 1–2, 3+), using patients with Charlson Index score 0 as the reference group. We then stratified by stage and computed the absolute survival and MRRs according to comorbidity level, using patients with Charlson score 0 and localized tumour/FIGO I as the reference group. We adjusted for age and calendar time.

Results

Comorbidity was more common among patients with an advanced stage of cancer. One- and five-year survival was higher in patients without comorbidity than in patients with registered comorbidity. After adjustment for age and calendar time, one-year MRRs declined from 1.8 to 1.4 and from 2.7 to 2.0, for patients with Charlson scores 1–2 and 3+, respectively. After adjustment for stage, the MRRs further declined to 1.3 and 1.8, respectively. Five-year MRRs declined similarly after adjustment for age, calendar time, and stage. The impact of severe comorbidity on mortality varied by stage, particularly among patients with tumours with regional spread/FIGO-stages II and III.

Conclusion

The presence of severe comorbidity was associated with an advanced stage of ovarian cancer. Mortality was higher among patients with comorbidities and the impact of comorbidity varied by stage.