Discordant genetic changes in ovarian and endometrial endometrioid carcinomas: a potential pitfall in molecular diagnosis

Guidelines to Aid in the Distinction of Endometrial and Endocervical Carcinomas, and the Distinction of Independent Primary Carcinomas of the Endometrium and Adnexa From Metastatic Spread Between These and Other Sites

In most cases of suspected endometrial neoplasia tumor origin can be correctly assigned according to a combination of clinical, radiologic, and pathologic features, even when the latter are based upon the examination of relatively small biopsy samples. However there are well-recognized exceptions to this rule which continue to create diagnostic difficulty, and sometimes difficulties persist even after the detailed examination of resection specimens. Among the most common problems encountered in practice are the distinction of primary endometrial and primary endocervical adenocarcinomas, and the determination of tumor origin when there is synchronous, multifocal involvement of gynecologic tract sites, for example the endometrium and the ovary. However, accurate diagnosis in these cases is important because this has significant staging, management and prognostic implications. In this review we discuss the value and limitations of key morphologic, immunophenotypic and molecular findings in these diagnostic scenarios.

Potential for Mitochondrial DNA Sequencing in the Differential Diagnosis of Gynaecological Malignancies

In the event of multiple synchronous gynecological lesions, a fundamental piece of information to determine patient management, prognosis, and therapeutic regimen choice is whether the simultaneous malignancies arise independently or as a result of metastatic dissemination. An example of synchronous primary tumors of the female genital tract most frequently described are ovarian and endometrial cancers. Surgical findings and histopathological examination aimed at resolving this conundrum may be aided by molecular analyses, although they are too often inconclusive. High mitochondrial DNA (mtDNA) variability and its propensity to accumulate mutations has been proposed by our group as a tool to define clonality. We showed mtDNA sequencing to be informative in synchronous primary ovarian and endometrial cancer, detecting tumor-specific mutations in both lesions, ruling out independence of the two neoplasms, and indicating clonality. Furthermore, we tested this method in another frequent simultaneously detected gynecological lesion type, borderline ovarian cancer and their peritoneal implants, which may be monoclonal extra-ovarian metastases or polyclonal independent masses. The purpose of this review is to provide an update on the potential use of mtDNA sequencing in distinguishing independent and metastatic lesions in gynecological cancers, and to compare the efficiency of molecular analyses currently in use with this novel method.

Clonality, Heterogeneity, and Evolution of Synchronous Bilateral Ovarian Cancer

Synchronous bilateral ovarian cancer (SBOC) represents a relatively frequent occurrence and clinically relevant diagnostic dilemma. Delineation of its clonal architecture, genetic heterogeneity, and evolutionary trajectories may have important implications for prognosis and management of patients with SBOC. Here, we describe the results of next-generation whole-exome or whole-genome sequencing of specimens from 12 SBOC cases and report that bilateral tumors from each individual display a comparable number of genomic abnormalities and similar mutational signatures of single-nucleotide variations. Clonality indices based on tumor-specific alterations supported monoclonal origins of SBOC. Each of the ovarian lesions was nevertheless oligoclonal, with inferred metastatic tumors harboring more subclones than their primary counterparts. The phylogenetic structure of SBOC indicated that most cancer cell dissemination occurred early, when the primary carcinoma was still relatively small (<100 million cells). Accordingly, the mutation spectra and mutational signatures of somatic variants exhibited pronounced spatiotemporal differences in each patient. Overall, these findings suggest that SBOCs are clonally related and form through pelvic spread rather than independent multifocal oncogenesis. Metastatic dissemination is often an early event, with dynamic mutational processes leading to divergent evolution and intratumor and intertumor heterogeneity, ultimately contributing substantially to phenotypic plasticity and diverse clinical course in SBOC. Cancer Res; 77(23); 6551-61. ©2017 AACR.

Mitochondrial DNA genotyping efficiently reveals clonality of synchronous endometrial and ovarian cancers

Simultaneous independent primary tumors of the female genital tract occur in 1-2% of gynecological cancer patients, 50-70% of which are synchronous tumors of the endometrium and ovary. Recognition of synchrony upon multiple tumors is crucial for correct prognosis, therapeutic choice, and patient management. Current guidelines for determining synchrony, based on surgical and histopathological findings, are often ambiguous and may require further molecular analyses. However, because of the uniqueness of each tumor and of its intrinsic heterogeneity, these analyses may sometimes be inconclusive. A role for mitochondrial DNA genotyping was previously demonstrated in the diagnosis of synchronous endometrial and ovarian carcinoma. We have analyzed 11 sample pairs of simultaneously revealed endometrial and ovarian cancers and have thereby applied conventional histopathological criteria, current molecular analyses (microsatellite instability, β-catenin immunohistochemical staining/CTNNB1 mutation screening), and mitochondrial DNA sequencing to distinguish separate independent tumors from metastases, comparing the performance and the informative potential of such methods. We have demonstrated that in ambiguous interpretations where histopathological criteria and canonical molecular methods fail to be conclusive, mitochondrial DNA analysis may act as a needle of balance and allow to formulate a diagnosis in 45.5% of our cases. Additional advantages of mitochondrial DNA genotyping, besides the high level of information we demonstrated here, are the easy implementation and the need for small amounts of starting material. Our results show that mitochondrial DNA genotyping may provide a substantial contribution to indisputably recognize the metastatic nature of simultaneously detected endometrial and ovarian cancers and may change the final staging and clinical management of these patients.

Preoperative identification of synchronous ovarian and endometrial cancers: the importance of appropriate workup

OBJECTIVE

For treatment of patients with both endometrial and ovarian cancer, it is important to discriminate between 2 primary tumors and metastatic disease. Currently, criteria are based on postoperative findings. The aim of this study was to determine whether clinical parameters can discriminate between these groups preoperatively and whether a practical guideline could improve appropriate workup and treatment.

METHODS

A total of 45 patients with a diagnosis of both endometrium and ovarian cancer between 1998 and 2009 and were included for analysis. Clinical and pathological data were obtained, and initial CA-125 was registered; patients had a diagnosis of 2 primary tumors or tumors with metastasis. All patients were reclassified according to workup and treatment.

RESULTS

Patients with synchronous primary tumors were significantly younger, presented more often with abnormal uterine bleeding, and had a lower initial CA-125 than both metastatic groups (P < 0.05). With age and CA-125 included in a polytomic logistic regression model, 83.3% of diagnoses could be classified correctly. In 15 of 17 patients presented with adnexal mass, workup was incomplete owing to lack on information of the endometrial status. In patients presenting with abnormal uterine bleeding, 13 of 21 patients had an incomplete workup leading to staging laparotomy secondary to initial surgical treatment in 2 patients.

CONCLUSIONS

Patients with synchronous endometrial and ovarian cancers are young, often present with abnormal uterine bleeding and have a low initial CA-125. Adequate workup with attention to both ovarian and endometrial status, especially in young patients with a wish to preserve fertility, is important to make the right decision for treatment.

A gene expression profile test for the differential diagnosis of ovarian versus endometrial cancers

We have developed a gene expression profile test (Pathwork Tissue of Origin Endometrial Test) that distinguishes primary epithelial ovarian and endometrial cancers in formalin-fixed, paraffin-embedded (FFPE) specimens using a 316–gene classification model. The test was validated in a blinded study using a pre-specified algorithm and microarray files for 75 metastatic, poorly differentiated or undifferentiated specimens with a known ovarian or endometrial cancer diagnosis. Measures of test performance include a 94.7% overall agreement with the known diagnosis, an area under the ROC curve (AUC) of 0.997 and a diagnostic odds ratio (DOR) of 406. Ovarian cancers (n=30) gave an agreement of 96.7% with the known diagnosis while endometrial cancers (n=45) gave an agreement of 93.3%. In a precision study, concordance in test results was 100%. Reproducibility in test results between three laboratories was 94.3%. The Tissue of Origin Endometrial Test can aid in resolving important differential diagnostic questions in gynecologic oncology.

Clonality in gynecologic neoplasms: is it time to reevaluate clonality studies in gynecologic neoplasms? Is it possible to confirm multicentricity with clonality studies?

This article reviews issues with clonality applied to gynecologic neoplasms. It is our opinion that the current interpretation of clonality studies in gynecologic neoplasms needs to be reevaluated because multicentricity, probably a common mechanism of tumor development in gynecology, cannot be confirmed with clonality.