Non-epithelial ovarian cancer: ESMO clinical recommendations for diagnosis, treatment and follow-up

Genome-Wide Identification and Validation of Gene Expression Biomarkers in the Diagnosis of Ovarian Serous Cystadenocarcinoma

Simple Summary

Despite ovarian serous adenocarcinoma (OSCA) is a high-incidence type of cancer, limited molecular screening methods are available and the diagnosis mostly occurs at a late stage. The aim of this study is screening the potential of gene expression for identifying OSCA-specific molecular biomarkers for improving diagnosis. A genome-wide survey was performed on high-throughput RNA-sequencing experiments on hundreds ovarian cancer samples and healthy ovarian tissues, providing a number of putative OSCA biomarkers, which were then validated on an independent sample set and using a different RNA-quantification technology. Combinations of gene expression biomarkers were identified, which showed high accuracy in discriminating OSCA tissues from the normal counterpart and from other tumor types. The detected biomarkers can improve the molecular diagnosis of OSCA on tissue samples and are, in principle, translatable to the analysis of liquid biopsies.

Abstract

Ovarian cancer is the second most prevalent gynecologic malignancy, and ovarian serous cystadenocarcinoma (OSCA) is the most common and lethal subtype of ovarian cancer. Current screening methods have strong limits on early detection, and the majority of OSCA patients relapse. In this work, we developed and cross-validated a method for detecting gene expression biomarkers able to discriminate OSCA tissues from healthy ovarian tissues and other cancer types with high accuracy. A preliminary ranking-based approach was applied, resulting in a panel of 41 over-expressed genes in OSCA. The RNA quantity gene expression of the 41 selected genes was then cross-validated by using NanoString nCounter technology. Moreover, we showed that the RNA quantity of eight genes (ADGRG1, EPCAM, ESRP1, MAL2, MYH14, PRSS8, ST14 and WFDC2) discriminates each OSCA sample from each healthy sample in our data set with sensitivity of 100% and specificity of 100%. For the other three genes (MUC16, PAX8 and SOX17) in combination, their RNA quantity may distinguish OSCA from other 29 tumor types.

Unusual Cases of Pure Malignant Germ Cell Tumors of the Ovary: A Case Series on 10 Years Experience at a Tertiary Care Center

Background

Malignant ovarian germ cell tumors (MOGCTs) are rare female cancers, constituting up to 10% of ovarian cancers. Dysgerminoma is the most common histological variant. Surgical removal of the tumor with optimal debulking is the treatment of choice. Multidrug chemotherapy following surgery offers high remission rates. Considering the prevalence of these tumors in adolescent and young females, fertility-sparing treatment is of paramount importance.

Methods

The data of all patients with ovarian malignancy admitted at a tertiary-care-teaching hospital from September 2009-March 2019 were analyzed. Ten patients of MOGCTs were treated in this period. The clinical features, radiological and biochemical findings, and management and treatment outcome were evaluated.

Results

The median age of patients was 23 years. Histological subtypes included immature teratoma (n=3), endodermal sinus tumor (n=4), and dysgerminoma (n=3). Tumor markers namely AFP, βHCG, and LDH increased in all except the patients with immature teratoma. Two patients with dysgerminoma were in the second trimester of pregnancy. All patients except one underwent surgery followed by BEP chemotherapy. Two patients had developed metastasis within six months of treatment and died. In seven patients, no evidence of disease was reported till date.

Conclusion

Management of antenatal patients with dysgerminoma by surgery followed by BEP chemotherapy has favorable prognosis. Fertility-sparing surgery with adjuvant chemotherapy offers great advantage in young girls. However, risk stratification based on prognostic factors should be implemented in order to individualize the treatment for achieving higher survival rates. The option for oocyte-cryopreservation prior to surgery must be discussed with patients desiring future fertlity.

Surveillance Only for High-risk FIGO Stage IA/IB Malignant Ovarian Germ Cell Tumors: Results From a National Cancer Database

OBJECTIVES

Investigate the use and outcomes of a surveillance only strategy for patients with high-risk stage I malignant ovarian germ cell tumors.

METHODS

Patients with International Federation of Gynecology and Obstetrics stage IA/IB grade 2 or 3 immature teratoma, yolk sac, or mixed germ cell tumor diagnosed between 2004 and 2014 who had at least 1 month of follow-up were drawn from the National Cancer Database. Overall survival (OS) was evaluated for each histologic subtype using Kaplan-Meier curves, and compared with the log-rank test.

RESULTS

A total of 497 patients were identified; 115 (23.1%) with grade 2 immature teratoma, 157 (31.6%) with grade 3 immature teratoma, 101 (20.3%) with yolk sac tumor, 124 (25%) with mixed germ cell tumor. Rate of adjuvant chemotherapy was 68.2% (655 patients), while rate of lymph node biopsy/dissection was 55.2%. A total of 19 (3.8%) deaths were observed at a median of 29.8 months. There was no difference in OS between patients who did and did not receive adjuvant chemotherapy with grade 2 (P=0.35) and grade 3 immature teratoma (P=0.47) or mixed germ cell tumors (P=0.55). Patients with yolk sac tumors those who received chemotherapy had better OS compared with those who did not, P=0.019; 5-year OS rates were 92.7% and 79.6%, respectively.

CONCLUSIONS

A surveillance only strategy for patients with stage I malignant ovarian germ cell tumors is associated with excellent survival outcomes for patients with grade 2 or 3 immature teratoma or mixed germ cell tumors.

Translational Theragnosis of Ovarian Cancer: where do we stand?

BACKGROUND

Ovarian cancer is the second most common gynecologic malignancy, accounting for approximately 220,000 deaths annually worldwide. Despite radical surgery and initial high response rates to platinum- and taxane-based chemotherapy, most patients experience a relapse, with a median progression-free survival of only 18 months. Overall survival is approximately 30% at 5 years from the diagnosis. In comparison, patients out from breast cancer are more than 80 % after ten years from the disease discovery. In spite of a large number of published fundamental and applied research, and clinical trials, novel therapies are urgently needed to improve outcomes of the ovarian cancer. The success of new drugs development in ovarian cancer will strongly depend on both fully genomic disease characterization and, then, availability of biomarkers able to identify women likely to benefit from a given new therapy.

METHODS

In this review, the focus is given to describe how complex is the diseases under the simple name of ovarian cancer, in terms of cell tumor types, histotypes, subtypes, and specific gene mutation or differently expressed in the tumor with respect the healthy ovary. The first- and second-line pharmacological treatment clinically used over the last fifty years are also described. Noteworthy achievements in vitro and in vivo tested new drugs are also summarized. Recent literature related to up to date ovarian cancer knowledge, its detection by biomarkers and chemotherapy was searched from several articles on Pubmed, Google Scholar, MEDLINE and various Governmental Agencies till April 2019.

RESULTS

The papers referenced by this review allow a deep analysis of status of the art in the classification of the several types of ovarian cancer, the present knowledge of diagnosis based on biomarkers and imaging techniques, and the therapies developed over the past five decades.

CONCLUSION

This review aims at stimulating more multi-disciplinary efforts to identify a panel of novel and more specific biomarkers to be used to screen patients for a very early diagnosis, to have prognosis and therapy efficacy indications. The desired final goal would be to have available tools allowing to reduce the recurrence rate, increase both the disease progression free interval and of course the overall survival at five years from the diagnosis that today is still very low.

APC2 is critical for ovarian WNT signalling control, fertility and tumour suppression

BACKGROUND

Canonical WNT signalling plays a critical role in the regulation of ovarian development; mis-regulation of this key pathway in the adult ovary is associated with subfertility and tumourigenesis. The roles of Adenomatous polyposis coli 2 (APC2), a little-studied WNT signalling pathway regulator, in ovarian homeostasis, fertility and tumourigenesis have not previously been explored. Here, we demonstrate essential roles of APC2 in regulating ovarian WNT signalling and ovarian homeostasis.

METHODS

A detailed analysis of ovarian histology, gene expression, ovulation and hormone levels was carried out in 10 week old and in aged constitutive APC2-knockout (Apc2-/-) mice (mixed background). Statistical significance for qRT-PCR data was determined from 95% confidence intervals. Significance testing was performed using 2-tailed Student's t-test, when 2 experimental cohorts were compared. When more were compared, ANOVA test was used, followed by a post-hoc test (LSD or Games-Howell). P-values of < 0.05 were considered statistically significant.

RESULTS

APC2-deficiency resulted in activation of ovarian WNT signalling and sub-fertility driven by intra-ovarian defects. Follicular growth was perturbed, resulting in a reduced rate of ovulation and corpora lutea formation, which could not be rescued by administration of gonadotrophins. Defects in steroidogenesis and follicular vascularity contributed to the subfertility phenotype. Tumour incidence was assessed in aged APC2-deficient mice, which also carried a hypomorphic Apc allele. APC2-deficiency in these mice resulted in predisposition to granulosa cell tumour (GCT) formation, accompanied by acute tumour-associated WNT-signalling activation and a histologic pattern and molecular signature seen in human adult GCTs.

CONCLUSIONS

Our work adds APC2 to the growing list of WNT-signalling members that regulate ovarian homeostasis, fertility and suppress GCT formation. Importantly, given that the APC2-deficient mouse develops tumours that recapitulate the molecular signature and histological features of human adult GCTs, this mouse has excellent potential as a pre-clinical model to study ovarian subfertility and transitioning to GCT, tumour biology and for therapeutic testing.

Budget impact of niraparib as maintenance treatment in recurrent ovarian cancer following platinum-based chemotherapy

Aim: To estimate financial implications of adopting niraparib as maintenance treatment in recurrent ovarian cancer. Materials & methods: A model was developed to estimate the budget impact of treating patients with niraparib compared with alternative maintenance treatment options (olaparib, rucaparib, bevacizumab or ‘watch and wait’) over 3 years. Results: For a hypothetical plan with 1 million lives representative of US/Medicare-only populations, projected cost savings with niraparib were US$78,721/$293,723, $276,671/$1,009,729 and $353,585/$1,289,712 at years 1, 2 and 3, respectively. Sensitivity analyses showed prices of niraparib, rucaparib and olaparib to have the most significant impact on the budget. Conclusion: Factoring in all treatment-related costs, the use of niraparib could result in significant cost savings compared with other maintenance treatment options.

Risk scores to guide referral decisions for people with suspected ovarian cancer in secondary care: a systematic review and cost-effectiveness analysis

BACKGROUND

Ovarian cancer is the sixth most common cancer in UK women and can be difficult to diagnose, particularly in the early stages. Risk-scoring can help to guide referral to specialist centres.

OBJECTIVES

To assess the clinical and cost-effectiveness of risk scores to guide referral decisions for women with suspected ovarian cancer in secondary care.

METHODS

Twenty-one databases, including MEDLINE and EMBASE, were searched from inception to November 2016. Review methods followed published guidelines. The meta-analysis using weighted averages and random-effects modelling was used to estimate summary sensitivity and specificity with 95% confidence intervals (CIs). The cost-effectiveness analysis considered the long-term costs and quality-adjusted life-years (QALYs) associated with different risk-scoring methods, and subsequent care pathways. Modelling comprised a decision tree and a Markov model. The decision tree was used to model short-term outcomes and the Markov model was used to estimate the long-term costs and QALYs associated with treatment and progression.

RESULTS

Fifty-one diagnostic cohort studies were included in the systematic review. The Risk of Ovarian Malignancy Algorithm (ROMA) score did not offer any advantage over the Risk of Malignancy Index 1 (RMI 1). Patients with borderline tumours or non-ovarian primaries appeared to account for disproportionately high numbers of false-negative, low-risk ROMA scores. (Confidential information has been removed.) To achieve similar levels of sensitivity to the Assessment of Different NEoplasias in the adneXa (ADNEX) model and the International Ovarian Tumour Analysis (IOTA) group's simple ultrasound rules, a very low RMI 1 decision threshold (25) would be needed; the summary sensitivity and specificity estimates for the RMI 1 at this threshold were 94.9% (95% CI 91.5% to 97.2%) and 51.1% (95% CI 47.0% to 55.2%), respectively. In the base-case analysis, RMI 1 (threshold of 250) was the least effective [16.926 life-years (LYs), 13.820 QALYs] and the second cheapest (£5669). The IOTA group's simple ultrasound rules (inconclusive, assumed to be malignant) were the cheapest (£5667) and the second most effective [16.954 LYs, 13.841 QALYs], dominating RMI 1. The ADNEX model (threshold of 10%), costing £5699, was the most effective (16.957 LYs, 13.843 QALYs), and compared with the IOTA group's simple ultrasound rules, resulted in an incremental cost-effectiveness ratio of £15,304 per QALY gained. At thresholds of up to £15,304 per QALY gained, the IOTA group's simple ultrasound rules are cost-effective; the ADNEX model (threshold of 10%) is cost-effective for higher thresholds.

LIMITATIONS

Information on the downstream clinical consequences of risk-scoring was limited.

CONCLUSIONS

Both the ADNEX model and the IOTA group's simple ultrasound rules may offer increased sensitivity relative to current practice (RMI 1); that is, more women with malignant tumours would be referred to a specialist multidisciplinary team, although more women with benign tumours would also be referred. The cost-effectiveness model supports prioritisation of sensitivity over specificity. Further research is needed on the clinical consequences of risk-scoring.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016053326.

FUNDING DETAILS

The National Institute for Health Research Health Technology Assessment programme.

MicroRNA expression profiles in non‑epithelial ovarian tumors

Ovarian germ cell tumors (OGCTs) and sex cord stromal tumors (SCSTs) are rare gynecologic tumors that are derived from germ and stromal cells, respectively. Unlike their epithelial counterparts, molecular pathogenesis of these tumor types is still poorly understood. Here, we characterized microRNA (miRNA) expression profiles of 9 OGCTs (2 malignant and 7 benign) and 3 SCSTs using small RNA sequencing. We observed significant miRNA expression variations among the three tumor groups. To further demonstrate the biological relevance of our findings, we selected 12 miRNAs for validation in an extended cohort of 16 OGCTs (9 benign and 7 malignant) and 7 SCSTs by reverse transcription-quantitative polymerase chain reaction. Higher expression of miR‑373‑3p, miR‑372‑3p and miR‑302c‑3p and lower expression of miR‑199a‑5p, miR‑214‑5p and miR‑202‑3p were reproducibly observed in malignant OGCTs as compared to benign OGCTs or SCSTs. Comparing with benign OGCTs, miR‑202c‑3p and miR‑513c‑5p were more abundant in SCSTs. Additionally, we examined Beclin 1 (BECN1), a target of miR‑199a‑5p, in the clinical samples using western blot analysis. Our results show that BECN1 expression was higher in malignant OGCTs than benign OGCTs, which is concordant with their lower miR‑199a‑5p expression. This study suggests that these miRNAs may have potential value as tumor markers and implications for further understanding the molecular basis of these tumor types.

The Effect of Breastfeeding Duration and Parity on the Risk of Epithelial Ovarian Cancer: A Systematic Review and Meta-analysis

Objectives

We conducted a systematic review and meta-analysis to summarize current evidence regarding the association of parity and duration of breastfeeding with the risk of epithelial ovarian cancer (EOC).

Methods

A systematic search of relevant studies published by December 31, 2015 was performed in PubMed and EMBASE. A random-effect model was used to obtain the summary relative risks (RRs) and 95% confidence intervals (CIs).

Results

Thirty-two studies had parity categories of 1, 2, and ≥3. The summary RRs for EOC were 0.72 (95% CI, 0.65 to 0.79), 0.57 (95% CI, 0.49 to 0.65), and 0.46 (95% CI, 0.41 to 0.52), respectively. Small to moderate heterogeneity was observed for one birth (p<0.01; Q=59.46; I²=47.9%). Fifteen studies had breastfeeding categories of <6 months, 6-12 months, and >13 months. The summary RRs were 0.79 (95% CI, 0.72 to 0.87), 0.72 (95% CI, 0.64 to 0.81), and 0.67 (95% CI, 0.56 to 0.79), respectively. Only small heterogeneity was observed for <6 months of breastfeeding (p=0.17; Q=18.79, I²=25.5%). Compared to nulliparous women with no history of breastfeeding, the joint effects of two births and <6 months of breastfeeding resulted in a 0.5-fold reduced risk for EOC.

Conclusions

The first birth and breastfeeding for <6 months were associated with significant reductions in EOC risk.

Cancer genomics: why rare is valuable

Rare conditions are sometimes ignored in biomedical research because of difficulties in obtaining specimens and limited interest from fund raisers. However, the study of rare diseases such as unusual cancers has again and again led to breakthroughs in our understanding of more common diseases. It is therefore unsurprising that with the development and accessibility of next-generation sequencing, much has been learnt from studying cancers that are rare and in particular those with uniform biological and clinical behavior. Herein, we describe how shotgun sequencing of cancers such as granulosa cell tumor, endometrial stromal sarcoma, epithelioid hemangioendothelioma, ameloblastoma, small-cell carcinoma of the ovary, clear-cell carcinoma of the ovary, nonepithelial ovarian tumors, chondroblastoma, and giant cell tumor of the bone has led to rapidly translatable discoveries in diagnostics and tumor taxonomies, as well as providing insights into cancer biology.

Gynecologic Cancer Intergroup (GCIG) consensus review for ovarian germ cell tumors

Most women diagnosed with malignant ovarian germ cell tumors have curable disease and experience excellent survival with manageable treatment-associated morbidity, related both to tumor biology and improvements in treatment over the last 4 decades. Malignant ovarian germ cell tumors occur predominantly in girls, adolescents, and young women and are often unilateral tumors of early stage, although advanced-stage disease occurs in approximately 30% of patients. Tumors are usually chemosensitive, thereby allowing fertility-sparing surgery in most women with high chance of cure. Differences in practice do exist among providers in various subspecialties and geographic areas. In most settings, collaborative efforts among specialties allow the optimal treatment of women with these rare tumors, and implementation of standard guidelines at an international level should translate to effective clinical trial design, rapid accrual to clinical trials, and universally improved patient outcomes. This consensus guideline represents a summary of recommendations for diagnosis and management that has been agreed upon by cooperative groups worldwide. It builds upon individual publications including previously published summary documents and provides the most current practice standards validated worldwide.

Ovarian cancer: genomic analysis

OBJECTIVES

Despite improvements in the management of ovarian cancer patients over the last 30 years, there has been only a minimal improvement in overall survival. While targeted therapeutic approaches for the treatment of cancer have evolved, major challenges in ovarian cancer research persist, including the identification of predictive biomarkers with clinical relevance, so that empirical drug selection can be avoided. In this article, we review published genomic analysis studies including data generated in our laboratory and how they have been incorporated into modern clinical trials in a rational and effective way.

METHODS

Multiple published genomic analysis studies were collected for review and discussion with emphasis on their potential clinical applicability.

RESULTS

Genomic analysis has been shown to be a powerful tool to identify dysregulated genes, aberrantly activated pathways and to uncover uniqueness of subclasses of ovarian tumors. The application of this technology has provided a solid molecular basis for different clinical behaviors associated with tumor histology and grade. Genomic signatures have been obtained to predict clinical end points for patients with cancer, including response rates, progression-free survival, and overall survival. In addition, genomic analysis has provided opportunities to identify biomarkers, which either result in a modification of existing clinical management or to stratification of patients to novel therapeutic approaches designed as clinical trials.

CONCLUSIONS

Genomic analyses have accelerated the identification of relevant biomarkers and extended our understanding of the molecular biology of ovarian cancer. This in turn, will hopefully lead to a paradigm shift from empirical, uniform treatment to a more rational, personalized treatment of ovarian cancers. However, validation of potential biomarkers on both the statistical and biological levels is needed to confirm they are of clinical relevance, in order to increase the likelihood that the desired outcome can be predicted and achieved.

Treatment outcomes of female germ cell tumors: the Egyptian National Cancer Institute experience

INTRODUCTION

Female germ cell tumors (GCTS) are rare tumors that carry a good prognosis.

AIM

To report the experience of the Egyptian National Cancer Institute (ENCI) in managing female GCTs.

METHODS

This retrospective study included 19 females with ovarian GCTs presenting to the ENCI between 2006 and 2010.

RESULTS

The median age was 23years. Ovaries were the primary site in all patients. Dysgerminoma and teratoma were the predominant pathologies followed by mixed GCT in females. Unilateral ovariectomy or ovarian tumorectomy were the classic surgical procedures with R0 resection being feasible in most cases. Surveillance was adopted in six patients with stage I disease. Chemotherapy was administered in 63% of ovarian GCTs with BEP being the commonest regimen with reasonable tolerability and good response rates. The median OS and EFS were not reached. The projected 5-year OS rate was 93.8%. Both OS and EFS were better in patients responding to chemotherapy than non-responders (p<0.002). Stage of disease did not significantly affect OS or EFS.

CONCLUSIONS

Female GCTs rarely affect Egyptian females. They have good prognosis.

BRCA1/2 mutation analysis in 41 ovarian cell lines reveals only one functionally deleterious BRCA1 mutation

Mutations in BRCA1/2 increase the risk of developing breast and ovarian cancer. Germline BRCA1/2 mutations occur in 8.6-13.7% of unselected epithelial ovarian cancers, somatic mutations are also frequent. BRCA1/2 mutated or dysfunctional cells may be sensitive to PARP inhibition by synthetic lethality. The aim of this study is to comprehensively characterise the BRCA1/2 status of a large panel of ovarian cancer cell lines available to the research community to assist in biomarker studies of novel drugs and in particular of PARP inhibitors. The BRCA1/2 genes were sequenced in 41 ovarian cell lines, mRNA expression of BRCA1/2 and gene methylation status of BRCA1 was also examined. The cytotoxicity of PARP inhibitors olaparib and veliparib was examined in 20 cell lines. The cell line SNU-251 has a deleterious BRCA1 mutation at 5564G > A, and is the only deleterious BRCA1/2 mutant in the panel. Two cell lines (UPN-251 and PEO1) had deleterious mutations as well as additional reversion mutations that restored the protein functionality. Heterozygous mutations in BRCA1/2 were relatively common, found in 14.6% of cell lines. BRCA1 was methylated in two cell lines (OVCAR8, A1847) and there was a corresponding decrease in gene expression. The BRCA1 methylated cell lines were more sensitive to PARP inhibition than wild-type cells. The SNU-251 deleterious mutant was more sensitive to PARP inhibition, but only in a long-term exposure to correct for its slow growth rate. Cell lines derived from metastatic disease are significantly more resistant to veliparib (2.0 fold p = 0.03) compared to those derived from primary tumours. Resistance to olaparib and veliparib was correlated Pearsons-R 0.5393, p = 0.0311. The incidence of BRCA1/2 deleterious mutations 1/41 cell lines derived from 33 different patients (3.0%) is much lower than the population incidence. The reversion mutations and high frequency of heterozygous mutations suggest that there is a selective pressure against BRCA1/2 in cell culture similar to the selective pressure seen in the clinic after treatment with chemotherapy. PARP inhibitors may be useful in patients with BRCA1 deleterious mutations or gene methylation.

Major clinical research advances in gynecologic cancer in 2012

Ten topics were chosen among major clinical research achievements in gynecologic oncology in 2012. For ovarian cancer, comprehensive review of the history of bevacizumab studies was followed by poly adenosine diphosphate [ADP]-ribose polymerase (PARP) inhibitors and other molecular targeted agents such as epidermal growth factor receptor tyrosine kinase inhibitor and AMG 386. For the development of genomic study in gynecologic cancers, BRCA and DICER1 mutations were covered in epithelial and nonepithelial ovarian cancer, respectively. For endometrial cancer, targeted agents including mammalian target of rapamycin (mTOR) inhibitors and bevacizumab were discussed. Radiation therapy "sandwiched" between combination chemotherapy schedules for the treatment of uterine papillary serous carcinoma was also reviewed. Preoperative prediction of lymph node metastasis, definition of low-risk group, and recurrence and survival outcomes of laparoscopic approaches were addressed. For cervical cancer, we reviewed long-term benefit of human papillomavirus test and efficacy of paclitaxel/carboplatin versus paclitaxel/cisplatin in stage IVB, persistent or recurrent disease. In addition, the effect of three dimensional image-based high-dose rate brachytherapy was also reviewed. For vulvar cancer, the diagnostic value of sentinel lymph node biopsy was discussed. For breast cancer, positive results of three outstanding phase III randomized clinical trials, CLEOPATRA, EMILIA, and BOLERO-2 were introduced. Lastly, updates of major practice guidelines were summarized.

Outcome and risk factors for recurrence in malignant ovarian germ cell tumors: a MITO-9 retrospective study

AIMS

This study aimed to investigate the outcome of patients with malignant ovarian germ cell tumors (MOGCTs) and to define the risk factors for recurrence.

METHODS

A total of 123 patients with MOGCTs were retrospectively reviewed among MITO centers. Eighty-one patients had primary treatment in a MITO center, whereas the other 42 were referred for adjuvant chemotherapy or recurrence. The clinicopathologic characteristics were evaluated for association with relapse or death.

RESULTS

Median age was 24 years (range, 11-76 years). Forty-nine (39.8%) had dysgerminomas, 35 (28.5%) had immature teratomas, 12 (9.8%) had mixed germ cell tumors, 26 (21.1%) had yolk sac tumors, and 1 (0.8%) had embryonal carcinoma. International Federation of Gynecology and Obstetrics stage distribution was as follows: stage I, 87 (70.7%); stage II, 3 (2.4%); stage III, 29 (23.6%); and stage IV, 4 (3.3%). Fertility-sparing surgery was performed in 92 patients, whereas the remaining 31 received radical surgery; 65.8% of patients received adjuvant chemotherapy. Recurrence rate was 17.8% and the median time to recurrence was 9 months. Univariate and multivariate analyses showed that patient age (>45 years) and treatment outside a referral (MITO) center were the most important predictors of recurrence. The 5-year overall survival rate was 88.8%, with a median follow-up of 61 months. Univariate and multivariate analyses demonstrated that stage greater than I and yolk sac tumors were independent poor prognostic indicators.

CONCLUSIONS

This study confirms that MOGCTs have excellent prognosis, with 5-year overall survival rates of 95.6% and 73.2% in stage I and advanced stages, respectively. Age older than 45 years and treatment not in a referral center are independent risk factors for recurrence, whereas stage greater than I and yolk sac histology are independent poor prognostic indicators.

Recurrent somatic DICER1 mutations in nonepithelial ovarian cancers

BACKGROUND

Germline truncating mutations in DICER1, an endoribonuclease in the RNase III family that is essential for processing microRNAs, have been observed in families with the pleuropulmonary blastoma-family tumor and dysplasia syndrome. Mutation carriers are at risk for nonepithelial ovarian tumors, notably sex cord-stromal tumors.

METHODS

We sequenced the whole transcriptomes or exomes of 14 nonepithelial ovarian tumors and noted closely clustered mutations in the region of DICER1 encoding the RNase IIIb domain of DICER1 in four samples. We then sequenced this region of DICER1 in additional ovarian tumors and in certain other tumors and queried the effect of the mutations on the enzymatic activity of DICER1 using in vitro RNA cleavage assays.

RESULTS

DICER1 mutations in the RNase IIIb domain were found in 30 of 102 nonepithelial ovarian tumors (29%), predominantly in Sertoli-Leydig cell tumors (26 of 43, or 60%), including 4 tumors with additional germline DICER1 mutations. These mutations were restricted to codons encoding metal-binding sites within the RNase IIIb catalytic centers, which are critical for microRNA interaction and cleavage, and were somatic in all 16 samples in which germline DNA was available for testing. We also detected mutations in 1 of 14 nonseminomatous testicular germ-cell tumors, in 2 of 5 embryonal rhabdomyosarcomas, and in 1 of 266 epithelial ovarian and endometrial carcinomas. The mutant DICER1 proteins had reduced RNase IIIb activity but retained RNase IIIa activity.

CONCLUSIONS

Somatic missense mutations affecting the RNase IIIb domain of DICER1 are common in nonepithelial ovarian tumors. These mutations do not obliterate DICER1 function but alter it in specific cell types, a novel mechanism through which perturbation of microRNA processing may be oncogenic. (Funded by the Terry Fox Research Institute and others.).