Mixed Ovarian Epithelial Carcinomas With Clear Cell and Serous Components are Variants of High-grade Serous Carcinoma: An Interobserver Correlative and Immunohistochemical Study of 32 Cases

Integrated genomic/epigenomic analysis stratifies subtypes of clear cell ovarian carcinoma, highlighting their cellular origin

The cellular origin of clear cell ovarian carcinoma (CCOC), a major histological subtype of ovarian carcinoma remains elusive. Here, we explored the candidate cellular origin and identify molecular subtypes using integrated genomic/epigenomic analysis. We performed whole exome-sequencing, microarray, and DNA methylation array in 78 CCOC samples according to the original diagnosis. The findings revealed that ARID1A and/or PIK3CA mutations were mutually exclusive with DNA repair related genes, including TP53, BRCA1, and ATM. Clustering of CCOC and other ovarian carcinomas (n = 270) with normal tissues from the fallopian tube, ovarian surface epithelium, endometrial epithelium, and pelvic peritoneum mesothelium (PPM) in a methylation array showed that major CCOC subtypes (with ARID1A and/or PIK3CA mutations) were associated with the PPM-lile cluster (n = 64). This cluster was sub-divided into three clusters: (1) mismatch repair (MMR) deficient with tumor mutational burden-high (n = 2), (2) alteration of ARID1A (n = 51), and (3) ARID1A wild-type (n = 11). The remaining samples (n = 14) were subdivided into (4) ovarian surface epithelium-like (n = 11) and (5) fallopian tube-like (considered as high-grade serous histotype; n = 3). Among these, subtypes (1-3) and others (4 and 5) were found to be associated with immunoreactive signatures and epithelial-mesenchymal transition, respectively. These results contribute to the stratification of CCOC into biological subtypes.

Impact of the number of cycles of platinum-based chemotherapy for early stage ovarian clear cell carcinoma on survival: a retrospective study

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is a unique subtype of ovarian epithelial ovarian cancer. The number of chemotherapy cycles for early-stage patients is still debated. This study aimed to evaluate whether at least 4 cycles of adjuvant platinum-based chemotherapy have better prognostic value than 1-3 cycles in early-stage OCCC.

METHODS

We retrospectively retrieved data from 102 patients with stage I-IIA OCCC between 2008 and 2017. All patients underwent complete surgical staging followed by adjuvant platinum-based chemotherapy. Kaplan-Meier curves and Multivariate Cox analysis were performed to estimate 5-year overall survival (OS) and progression-free (PFS) according to the number of chemotherapy cycles.

RESULTS

Among stage I-IIA disease, twenty (19.6%) patients received 1-3 cycles, and eighty-two (80.4%) patients received at least 4 cycles of adjuvant chemotherapy. Univariate analysis revealed that the patients in 1-3cycles group had not significantly improved 5-year OS and PFS than those in the ≥ 4 cycles group (5-year OS: hazard ratio [HR] 1.21; 95% confidence interval [CI] 0.25- 5.78, p = 0.1), and 5-year PFS: HR 0.79; 95% CI 0.26- 2.34, p = 0.1). In the multivariate analysis, there was no impact of 1-3 versus ≥ 4 cycles of chemotherapy on 5-year OS (HR 1.21, 95% CI 0.25-3.89, p = 0.8) or 5-year PFS (HR 0.94, 95% CI 0.32-2.71, p = 0.9). The potential independent risk factors associated with 5-year OS and PFS included the surgery approach and FIGO stage.

CONCLUSION

The number of cycles of platinum-based chemotherapy could not be associated with a survival benefit for patients with early-stage OCCC.

The diverse morphology and immunophenotype of ovarian endometrioid carcinomas

Endometrioid carcinoma (EC) accounts for approximately 10-12% of ovarian epithelial malignancies but compared to its relative frequency, results in a disproportionate number of diagnostically difficult cases with potential for misdiagnosis. In this review the protean and diverse morphologies of ovarian EC are discussed, including 'metaplastic' changes, EC with spindle cell differentiation/corded and hyalinised features and EC with sex cord-like formations. The propensity for 'transdifferentiation' in ovarian ECs is also discussed, one example being the association with a somatically derived yolk sac tumour. Although immunohistochemistry may be extremely useful in diagnosing EC and in distinguishing between EC and other ovarian epithelial malignancies, metastatic neoplasms and sex cord-stromal tumours, this review also discusses the propensity for ovarian EC to exhibit an aberrant immunophenotype which may compound diagnostic uncertainty. The genomic characteristics of these tumours and the recent 'incorporation' of seromucinous carcinoma into the EC category are also discussed.

Nanoparticle-Based Follistatin Messenger RNA Therapy for Reprogramming Metastatic Ovarian Cancer and Ameliorating Cancer-Associated Cachexia

This study presents the first messenger RNA (mRNA) therapy for metastatic ovarian cancer and cachexia-induced muscle wasting based on lipid nanoparticles that deliver follistatin (FST) mRNA predominantly to cancer clusters following intraperitoneal administration. The secreted FST protein, endogenously synthesized from delivered mRNA, efficiently reduces elevated activin A levels associated with aggressive ovarian cancer and associated cachexia. By altering the cancer cell phenotype, mRNA treatment prevents malignant ascites, delays cancer progression, induces the formation of solid tumors, and preserves muscle mass in cancer-bearing mice by inhibiting negative regulators of muscle mass. Finally, mRNA therapy provides synergistic effects in combination with cisplatin, increasing the survival of mice and counteracting muscle atrophy induced by chemotherapy and cancer-associated cachexia. The treated mice develop few nonadherent tumors that are easily resected from the peritoneum. Clinically, this nanomedicine-based mRNA therapy can facilitate complete cytoreduction, target resistance, improve resilience during aggressive chemotherapy, and improve survival in advanced ovarian cancer.

Genomic and Molecular Abnormalities in Gynecologic Clear Cell Carcinoma

Gynecologic clear cell carcinoma is a rare histology, accounting for ~5% of all ovarian and endometrial cancers in the United States. Compared to other types of gynecologic cancer, they are generally less responsive to standard therapy and have an overall worse prognosis. In addition, mounting evidence suggests that the landscape of genetic and molecular abnormalities observed in these tumors is distinct from other cancers that arise from the same sites of origin. On a molecular level, these tumors characteristically display upregulation of the PI3K-AKT-mTOR and RAS-RAF-MAPK signaling axes, frequent loss of ARID1a, and overexpression of MDM2. Evidence also suggests that these tumors are more likely to express programmed death ligand 1 or demonstrate microsatellite instability than other gynecologic cancers. Despite these important differences, there has been relatively little investigation into histology-specific treatment of clear cell gynecologic cancers, representing an opportunity for new drug development. In this article, we review the unique genetic and molecular features of gynecologic clear cell cancers with an emphasis on potential therapeutic targets. The results of completed studies of treatment for clear cell carcinoma are also presented. We conclude with a discussion of ongoing clinical trials and potential avenues for future study.

Molecular subtypes of clear cell carcinoma of the endometrium: Opportunities for prognostic and predictive stratification

OBJECTIVE

Our aim was to characterize the pathological, molecular and clinical outcomes of clear cell carcinoma of the endometrium (CCC).

METHODS

CCC underwent ProMisE (Proactive Molecular Risk Classifier for Endometrial Cancer) classification identifying four molecular subtypes: i) 'POLEmut' for ECs with pathogenic POLE mutations, ii) 'MMRd', if there is loss of mismatch repair proteins by immunohistochemistry (IHC), iii) 'p53wt' or iv) 'p53abn' based on p53 IHC staining. Clinicopathologic parameters, immune markers (CD3, CD8, CD79a, CD138, PD-1), ER, L1CAM, and outcomes were assessed.

RESULTS

52 CCCs were classified, including 1 (2%) POLEmut, 5 (10%) MMRd, 28 (54%) p53wt and 18 (35%) p53abn. Women with p53abn and p53wt CCCs were older than women with MMRd and POLEmut subtypes. p53wt CCC were distinct from typical p53wt endometrioid carcinomas; more likely to arise in older, thinner women, with advanced stage disease, LVSI and lymph node involvement, and a higher proportion ER negative, L1CAM overexpressing tumors with markedly worse outcomes. High levels of immune infiltrates (TIL^high) were observed in 75% of the CCC cohort. L1CAM overexpression was highest within p53abn and p53wt subtypes of CCC.

CONCLUSION

CCC is a heterogeneous disease encompassing all four molecular subtypes and a wide range of clinical outcomes. Outcomes of patients with POLEmut, MMRd and p53abn CCC are not distinguishable from those of other patients with these respective subtypes of EC; p53wt CCC, however, differ from endometrioid p53wt EC in clinical, pathological, molecular features and outcomes. Thus, p53wt CCC of endometrium appear to be a distinct clinicopathological entity within the larger group of p53wt ECs.

Pathology of Endometrioid and Clear Cell Carcinoma of the Ovary

This review is an appraisal of the current state of knowledge of 2 enigmatic histotypes of ovarian carcinoma: endometrioid and clear cell carcinoma. Both show an association endometriosis and the hereditary nonpolyposis colorectal cancer (Lynch) syndrome, and both typically present at an early stage. Pathologic and immunohistochemical features that distinguish these tumors from high-grade serous carcinomas, each other, and other potential mimics are discussed, as are staging, grading, and molecular pathogenesis.

Survival Following Chemotherapy in Ovarian Clear Cell Carcinoma Is Not Associated with Pathological Misclassification of Tumor Histotype

PURPOSE

Although ovarian clear cell carcinomas (OCCC) are commonly resistant to platinum-based chemotherapy, good clinical outcomes are observed in a subset of patients. The explanation for this is unknown but may be due to misclassification of high-grade serous ovarian cancer (HGSOC) as OCCC or mixed histology.

EXPERIMENTAL DESIGN

To discover potential biomarkers of survival benefit following platinum-based chemotherapy, we ascertained a cohort of 68 Japanese and Australian patients in whom progression-free survival (PFS) and overall survival (OS) could be assessed. We performed IHC reclassification of tumors, and targeted sequencing and immunohistochemistry of known driver genes. Exome sequencing was performed in 10 patients who had either unusually long survival (N = 5) or had a very short time to progression (N = 5).

RESULTS

The majority of mixed OCCC (N = 6, 85.7%) and a small proportion of pure OCCC (N = 3, 4.9%) were reclassified as likely HGSOC. However, the PFS and OS of patients with misclassified samples were similar to that of patients with pathologically validated OCCC. Absent HNF1B expression was significantly correlated with longer PFS and OS (P = 0.0194 and 0.0395, respectively). Mutations in ARID1A, PIK3CA, PPP2R1A, and TP53 were frequent, but did not explain length of PFS and OS. An exploratory exome analysis of patients with favorable and unfavorable outcomes did not identify novel outcome-associated driver mutations.

CONCLUSIONS

Survival benefit following chemotherapy in OCCC was not associated with pathological misclassification of tumor histotype. HNF1B loss may help identify the subset of patients with OCCC with a more favorable outcome.

High-grade Endometrial Carcinomas: Morphologic and Immunohistochemical Features, Diagnostic Challenges and Recommendations

This review of challenging diagnostic issues concerning high-grade endometrial carcinomas is derived from the authors' review of the literature followed by discussions at the Endometrial Cancer Workshop sponsored by the International Society of Gynecological Pathologists in 2016. Recommendations presented are evidence-based, insofar as this is possible, given that the levels of evidence are weak or moderate due to small sample sizes and nonuniform diagnostic criteria used in many studies. High-grade endometrioid carcinomas include FIGO grade 3 endometrioid carcinomas, serous carcinomas, clear cell carcinomas, undifferentiated carcinomas, and carcinosarcomas. FIGO grade 3 endometrioid carcinoma is diagnosed when an endometrioid carcinoma exhibits >50% solid architecture (excluding squamous areas), or when an architecturally FIGO grade 2 endometrioid carcinoma exhibits marked cytologic atypia, provided that a glandular variant of serous carcinoma has been excluded. The most useful immunohistochemical studies to make the distinction between these 2 histotypes are p53, p16, DNA mismatch repair proteins, PTEN, and ARID1A. Endometrial clear cell carcinomas must display prototypical architectural and cytologic features for diagnosis. Immunohistochemical stains, including, Napsin A and p504s can be used as ancillary diagnostic tools; p53 expression is aberrant in a minority of clear cell carcinomas. Of note, clear cells are found in all types of high-grade endometrial carcinomas, leading to a tendency to overdiagnose clear cell carcinoma. Undifferentiated carcinoma (which when associated with a component of low-grade endometrioid carcinoma is termed "dedifferentiated carcinoma") is composed of sheets of monotonous, typically dyscohesive cells, which can have a rhabdoid appearance; they often exhibit limited expression of cytokeratins and epithelial membrane antigen, are usually negative for PAX8 and hormone receptors, lack membranous e-cadherin and commonly demonstrate loss of expression of DNA mismatch repair proteins and SWI-SNF chromatin remodeling proteins. Carcinosarcomas must show unequivocal morphologic evidence of malignant epithelial and mesenchymal differentiation.

The expression of IMP3 in 366 cases with ovarian carcinoma of high grade serous, endometrioid and clear cell subtypes

The clear cell (CCC), high grade serous (HGSC) and endometrioid (EC) ovarian carcinomas share overlapping histological features. The oncogene IMP3 is implicated in CCC with an elusive utility in differential diagnosis. We collected 366 cases with ovarian primary carcinomas to detect IMP3, Napsin-A and HNF-1β by immunochemistry. In 351 cases, the positive expression rate of IMP3 in CCC was significantly higher than that either in EC or HGSC (p < 0.01). The sensitivity of IMP3 in CCC was higher than Napsin-A but lower than HNF-1β (p < 0.01). The specificity of IMP3 in CCC was lower than Napsin-A but higher than HNF-1β (p < 0.01). The composite markers Napsin-A+/IMP3+ and the IMP3+/HNF-1β+/Napsin-A+ offered the highest odds ratio (p < 0.001), the highest specificity, the highest positive predictive value and the highest positive likelihood ratio. The ROC analysis showed that the combination of Napsin-A, HNF-1β and IMP3 offered the biggest AUC compared with either the singular marker performances or the other binary combinations (p < 0.001). In 15 cases of EC mixed with CCC, IMP3 showed a better discrimination value than the other two markers. Consequently, adding IMP3 to the diagnostic panel might provide some help with the pathological diagnosis of ovarian CCC.

Ovarian Clear Cell Carcinoma: From Morphology to Molecular Biology

Ovarian clear cell carcinoma (oCCC) is a distinctive subtype of ovarian carcinoma, with peculiar genetic and environmental risk factors, precursor lesions, molecular events during oncogenesis, patterns of spread, and response to treatment. Because of low response to chemotherapy and poor prognosis in advanced stages, there is growing interest in investigating the molecular pathways involved in oCCC development, in order to individualize novel/molecular targeted therapies. Until now, the main molecular genetic changes associated with oCCC remain to be identified, and, although several molecular changes have been reported in clear cell tumors, most studies have analyzed a limited number of cases; therefore, the true prevalence of those changes is not known. The present review will present the clinicopathologic features of oCCC, from morphology to molecular biology, discussing the diagnostic and treatment challenges of this intriguing ovarian carcinoma.

Missed therapeutic and prevention opportunities in women with BRCA-mutated epithelial ovarian cancer and their families due to low referral rates for genetic counseling and BRCA testing: A review of the literature

Answer questions and earn CME/CNE Fifteen percent of women with epithelial ovarian cancer have inherited mutations in the BRCA breast cancer susceptibility genes. Knowledge of her BRCA status has value both for the woman and for her family. A therapeutic benefit exists for the woman with cancer, because a new family of oral drugs, the poly ADP-ribose polymerase (PARP) inhibitors, has recently been approved, and these drugs have the greatest efficacy in women who carry the mutation. For her family, there is the potential to prevent ovarian cancer in those carrying the mutation by using risk-reducing surgery. Such surgery significantly reduces the chance of developing this, for the most part, incurable cancer. Despite these potential benefits, referral rates for genetic counseling and subsequent BRCA testing are low, ranging from 10% to 30%, indicating that these therapeutic and prevention opportunities are being missed. The authors have reviewed the relevant available literature. Topics discussed are BRCA and its relation to ovarian cancer, the rates of referral for genetic counseling/BRCA testing, reasons for these low rates, potential strategies to improve on those rates, lack of effectiveness of current screening strategies, the pros and cons of risk-reducing surgery, other prevention options, and the role and value of PARP inhibitors. CA Cancer J Clin 2017;67:493-506. © 2017 American Cancer Society.

Endometrial Serous Carcinoma With Clear-Cell Change: Frequency and Immunohistochemical Analysis

The diagnostic distinction between endometrial serous carcinoma (ESC) and endometrial clear-cell carcinoma (CCC) may occasionally be problematic, and one potentially contributing factor is the finding of clear cells in otherwise classic cases of ESC. This study aimed to define the frequency of this finding and comparatively assessed the immunophenotype of the clear cells. A review of 56 cases of ESC identified 8 (14.28%) with clear cells, representing 1% to 20% (median 7.5) of tumoral volume in these cases. In only 3 cases were clear cells discernible at low (×20) magnification. There was no significant difference in stage distribution or age between ESC patients with and without clear cells. The immunophenotypes of ESC-associated clear cells (group 1) were compared with foci of conventional ESC on another tissue block within the same case (group 2; n = 8) as well as a randomly selected cohort of CCC cases (group 3; n = 8). Groups 1 and 2 showed no significant differences regarding p53, ER, PR, Napsin-A, p504S, and hepatocyte nuclear factor 1β (HNF1β) expression, or regarding mitotic indices or Ki67 proliferation rate. In contrast, group 1 cases showed an immunophenotypic profile that was notably different from that of group 3 cases, with the former showing statistically significantly higher/more frequent expression of ER, PR, Ki67, and p53 and lower/less frequent expression of Napsin-A, p504S, and HNF1β. We conclude that clear-cell change is seen in 14% of ESCs and is discernible at low magnification in only 5%; these areas show an immunophenotype that is essentially identical to the associated background conventional ESC and are phenotypically dissimilar to CCC.

High-grade serous carcinoma of tubo-ovarian origin: recent developments

Extra-uterine high-grade serous carcinoma (HGSC) accounts for most of the morbidity and mortality associated with ovarian carcinoma, and is one of the leading causes of cancer death in women. Until recently our understanding of HGSC was very limited compared to other common cancers, and it has only been during the last 15 years that we have learned how to diagnose this ovarian carcinoma histotype accurately. Since then, however, there has been rapid progress, with identification of a precursor lesion in the fallopian tube, development of prevention strategies for both those with inherited susceptibility (hereditary breast and ovarian cancer syndrome) and without the syndrome, and elucidation of the molecular events important in oncogenesis. This molecular understanding has led to new treatment strategies for HGSC, with the promise of more to come in the near future. In this review we focus on these recent changes, including diagnostic criteria/differential diagnosis, primary site assignment, precursor lesions and the molecular pathology of HGSC.

Endometrial Carcinomas With Clear Cells: A Study of a Heterogeneous Group of Tumors Including Interobserver Variability, Mutation Analysis, and Immunohistochemistry With HNF-1β

Endometrial clear cell carcinoma (CC) is an uncommon tumor and often carries a poor prognosis. It has histologic features that overlap with other endometrial carcinomas and is frequently misclassified. Accurate classification is crucial, however, to improve treatment options. The objectives of this study were (1) to assess diagnostic interobserver variability among 5 gynecologic pathologists for tumors originally diagnosed as CC or with a component of CC (n=44); (2) to determine the utility of immunohistochemical markers estrogen receptor and HNF-1β; and (3) to detect mutations in select genes. Clinical data and morphologic features were also recorded. Agreement among reviewers was only moderate: only 46% of the original CC remained classified as such. After reclassification, estrogen receptor was positive in 8% of CC, 67% of endometrioid carcinomas (EC), and 47% of serous carcinomas (SC). Sensitivities of HNF-1β in CC, SC, and EC were 62%, 27%, and 17%, respectively, whereas specificity for CC versus EC or SC was 78%. Mutations in PIK3CA, PIK3R1, PTEN, KRAS, and NRAS were detected in 41% of 37 cases that had adequate material for study. At least 1 mutation was identified in 33% of CC, 67% of EC, and 33% of SC. This group of patients had poor outcomes: 72% of the patients with follow-up information had died of disease. In summary, this study suggests that the current pool of CC is a heterogeneous group of tumors from the morphologic, immunophenotypic, and molecular point of views and that only a percentage of them represent true CC.

Molecular Profiling of Clear Cell Ovarian Cancers: Identifying Potential Treatment Targets for Clinical Trials

Background

Advanced stage/recurrent clear cell ovarian cancers (CCOCs) are characterized by a low response to chemotherapy and a poor prognosis. There is growing interest in investigating novel/molecular targeted therapies in patients with CCOC in histotype-specific trials. However, CCOCs are not a uniform entity and comprise a number of molecular subtypes and it is unlikely that a single approach to treatment will be appropriate for all patients. The aim of this study was to analyze the results of a multiplatform profiling panel in CCOCs to identify potential therapeutic targets.

Patients and Methods

Tumor profiling was performed on 521 CCOCs. They were grouped into pure (n = 422) and mixed (n = 99) CCOC for analysis. Testing included a combination of DNA sequencing (including next-generation sequencing) using a 46-gene panel, immunohistochemistry, fluorescent or chromogenic in situ hybridization, and RNA fragment analysis.

Results

The most common findings were in the PIK3CA/Akt/mTOR pathway, with 61% of all CCOCs showing a molecular alteration in one of these pathway components. Next-generation sequencing revealed PIK3CA mutations in 50% of pure CCOCs. Significant differences were observed between pure and mixed CCOCs with respect to hormone receptor expression (9% vs 34.7% for ER, 13.45 vs 26.4% for PR), cMET (24.1% vs 11.6%), PD-1 tumor infiltrating lymphocytes (48.1% vs 100%), expression of PD-L1 (7.4% vs 25%), and TOPO1 (41% vs 27.1%) on immunohistochemistry, whereas next-generation sequencing revealed significant differences in mutation frequency in PIK3CA (50% vs 18.5%), TP53 (18.1% vs 57.7%), KRAS (12.4% vs 3.7%), and cMET (1.9% vs 11.1%).

Conclusions

This large study confirms that the PIK3CA/Akt/mTOR pathway is commonly altered in CCOCs, and highlights the significant differences between pure and mixed CCOCs. Clear cell ovarian cancers are molecularly heterogeneous and there are a number of potential therapeutic targets which could be tested in clinical trials.

Radiation Therapy for Recurrent Clear-Cell Cancer of the Ovary

Objective

Given the relative chemo-resistant nature of clear-cell gynecologic cancers, we investigated the utility of radiation therapy (RT) to treat recurrent clear-cell carcinoma (CCC) of the ovary.

Methods

A retrospective chart review of patients with recurrent CCC managed from 1994–2012 was conducted at 2 academic medical centers. Demographic and clinicopathologic factors were abstracted and evaluated using Pearson χ2 or t tests, Kaplan-Meier and Cox regression analyses.

Results

Fifty-three patients had recurrent CCC, and 24 (45.3%) of these patients received RT. There were no significant differences in age, stage, optimal cytoreduction, platinum response, or the percentage of patients that received more than 3 regimens of chemotherapy between the 2 groups. Patients who received RT for recurrent CCC were more likely to have had a focal recurrence (62.5% vs 10.3%, P ≤ 0.001) and to have undergone secondary cytoreduction (70.8% vs 10.3%, P ≤ 0.001). Of patients who received RT, 73.9% underwent surgery with or before their treatment. Five-year survival after recurrence was significantly higher in the group that received RT, 62.9% versus 18.8% (P = 0.002). In a multivariate analysis, platinum-sensitive disease and RT were associated with improved survival from recurrence, (hazard ratio, 0.26; 95% confidence interval, 0.08-0.81; P = 0.02 and hazard ratio, 0.28; 95% confidence interval, 0.09–0.90, P = 0.03, respectively).

Conclusions

In this cohort of patients with recurrent CCC, platinum-sensitive disease and RT are associated with improved survival. However, it is important to note that the majority of these patients underwent surgery along with RT, and it may be that the benefit of RT is limited to those who undergo secondary cytoreduction.

Clear cell carcinomas of the ovary: a mono-institutional study of 73 cases in China with an analysis of the prognostic significance of clinicopathological parameters and IMP3 expression

Background

Ovarian clear cell carcinoma (CCC) is an uncommon subtype of ovarian epithelial tumor. The prognostic significance of its clinicopathological parameters is discordant, with the exception of stage as the adverse prognostic factor. The present study aimed to evaluate the prognostic significance of its clinicopathological characteristics and the expression of IMP3 (Insulin-like growth factor-II mRNA-binding protein 3, IMP3 or IGF2BP3) in Chinese patients with primary pure CCC.

Methods

We collected clinicopathological data from 73 cases with a minimum of 5 years of follow-up and evaluated the expression of IMP3 by immunohistochemistry.

Results

In total, 49.3 % of the patients were in stage I. Advanced stages were closely related to poor prognosis of disease-free survival (DFS) and overall survival (OS) (P < 0.005). Patients with CCC coexisting with endometriosis tended to be younger and to have unilateral involvement but did not exhibit differences in prognosis compared with patients with CCC without endometriosis. Other histological features such as growth pattern, mitosis, and necrosis did not have prognostic significance. IMP3 was positive in 63 % of patients (46 of 73 cases); Thus, positive expression of IMP3 is an adverse prognostic marker in terms of OS (P = 0.012), even in stage I patients (P = 0.038).

Conclusions

The present study demonstrates that IMP3 expression is a prognostic marker, with the exception of stage. IMP3 represents a biomarker of unfavorable prognosis even in stage I patients.

Morphologic and Molecular Characteristics of Mixed Epithelial Ovarian Cancers

Epithelial ovarian cancer (EOC) consists of 5 major histotypes: high-grade serous carcinoma (HGSC), endometrioid carcinoma (EC), clear cell carcinoma (CCC), mucinous carcinoma (MC), and low-grade serous carcinoma (LGSC). Each can have a broad spectrum of morphologic appearances, and 1 histotype can closely mimic histopathologic features more typical of another. Historically, there has been a relatively high frequency of mixed, defined by 2 or more distinct histotypes present on the basis of routine histopathologic assessment, histotype carcinoma diagnoses (3% to 11%); however, recent immunohistochemical (IHC) studies identifying histotype-specific markers and allowing more refined histotype diagnoses suggest a much lower incidence. We reviewed hematoxylin and eosin-stained slides from 871 cases of EOC and found the frequency of mixed carcinomas to be 1.7% when modern diagnostic criteria are applied. Through international collaboration, we established a cohort totaling 22 mixed EOCs, consisting of 9 EC/CCC, 4 EC/LGSC, 3 HGSC/CCC, 2 CCC/MC, and 4 other combinations. We interrogated the molecular differences between the different components of each case using IHC, gene expression, and hotspot sequencing analyses. IHC data alone suggested that 9 of the 22 cases were not mixed tumors, as they presented a uniform immuno-phenotype throughout, and these cases most probably represent morphologic mimicry and variation within tumors of a single histotype. Synthesis of molecular data further reduces the incidence of mixed carcinomas. On the basis of these results, true mixed carcinomas with both morphologic and molecular support for the presence of >1 histotype within a given tumor represent <1% of EOCs.

Immunohistochemical Comparison of Ovarian and Uterine Endometrioid Carcinoma, Endometrioid Carcinoma With Clear Cell Change, and Clear Cell Carcinoma

Accurate distinction of clear cell carcinoma (CCC) from endometrioid carcinoma (EC) has important clinical implications, but, not infrequently, EC demonstrates clear cell change (EC-CC), mimicking CCC. We examined whether a panel of immunomarkers can help distinguish between these tumors. Sixty-four CCCs (40 ovarian and 24 uterine), 34 ECs (21 ovarian and 13 uterine), and 34 EC-CCs (6 ovarian and 28 uterine) were stained for HNF1β, BAF250a, Napsin A, ER, and PR. Intensity and extent of immunoreactivity was assessed. Fifty-seven of 64 (89%) CCCs, 14/34 (41%) EC-CCs, and 16/34 (47%) ECs expressed HNF1β, and 56/64 (88%) CCCs, 4/34 (12%) EC-CCs, and 1/34 (3%) ECs stained for Napsin A. Most CCCs demonstrated at least moderate and diffuse staining for both markers, whereas only focal and weak expression was identified in most EC-CC/EC. Compared to HNF1β, Napsin A showed increased specificity (93.0% vs. 55.9%, P<0.0001) and similar sensitivity (87.5% vs. 89.1%) in distinguishing CCC from EC-CC/EC. Thirteen of 64 (20%) CCCs, 6/34 (18%) EC-CCs, and 2/34 (6%) ECs showed loss of BAF250a. ER was expressed by 10/64 (16%) CCCs, 30/34 (88%) EC-CCs, and 33/34 (97%) ECs, whereas PR positivity was identified in 9/64 (14%) CCCs, 26/34 (77%) EC-CCs, and 33/34 (97%) ECs. The majority of EC and EC-CC demonstrated diffuse staining for ER/PR, whereas most CCCs showed very focal positivity. There is a statistically significant difference in HNF1β, Napsin A, ER, and PR immunoexpression between CCC and EC/EC-CC, with Napsin A being a more specific marker for CCC than HNF1β. Overall, the immunoprofile of EC-CC is more comparable to that of EC than CCC. The use of a panel of immunostains can help distinguish EC-CC from CCC.

Comparison of pure and mixed-type clear cell carcinoma of the ovary: a clinicopathological analysis of 341 Chinese patients

OBJECTIVE

This study aimed to analyze the clinicopathological features of pure and mixed-type ovarian clear cell carcinoma (CCC) in Chinese patients.

METHODS

Patients with ovarian CCC treated in our institution between 1982 and 2012 were identified by reviewing the database and medical charts. Patients were assigned into 2 groups based on histology (pure or mixed). Comparison of clinicopathological parameters was performed to determine the similarities and/or differences between pure and mixed CCC. Kaplan-Meier model was used in survival analysis.

RESULTS

Of 341 patients with ovarian CCC, 46 (13.5%) mixed tumors were identified, and the most common combination was clear cell/endometrioid, accounting for 56.5%. Patients with mixed-type CCC tended to have higher level of serum cancer antigen 125 (P = 0.023) and advanced tumor stage (P = 0.001). No difference was observed in other features including age, tumor size, residual disease, lymph node metastasis, and coexisting endometriosis. Tumor recurrence occurred in 47.8% and 58.1% in patients with pure and mixed histology, respectively (P = 0.209). Two groups had comparable platinum-sensitive disease (42.1% in pure and 44.0% in mixed type, P = 0.860). Patients with pure CCC had an improved median survival (105 vs 56 months), although statistical significance was not achieved. Histology subclassification of mixed tumor revealed that patients with clear cell/endometrioid histology had better survival outcome than those with clear cell/serous type (median survival, 140 vs 43 months, P = 0.004; median progression-free survival, 49 vs 12 months, P = 0.001).

CONCLUSIONS

Patients with mixed CCC tended to have elevated serum cancer antigen 125 and advanced tumor stage. However, no significant difference was observed between the pure and mixed tumors regarding prognosis.

Specimen quality evaluation in Canadian biobanks participating in the COEUR repository

Human biological specimens are important for translational research programs such as the Canadian Ovarian Experimental Unified Resource (COEUR) funded by the Terry Fox Research Institute. Sample quality is an important consideration, as it directly impacts the quality of ensuing research. The aim of the present study was to determine the quality of tissues collected from different sites contributing to the COEUR cohort. Samples from high-grade serous ovarian tumors (fresh frozen and corresponding paraffin-embedded tissues) were provided by nine participating Canadian biobanks. All samples were shipped to a central site using a Standard Operating Protocol (SOP). DNA and RNA extraction was conducted by the quality control division of the Canadian Tumor Repository Network (CTRNet). DNA quality was determined by ß-globin gene PCR amplification, and RNA quality by the RNA integrity number (RIN), as measured by the Agilent BioAnalyzer. DNA of acceptable quality had at least three bands of ß-globin amplified from DNA (n=115/135), and a RIN number ≥7 was considered very good for RNA (n=80/135). Sample preparation and storage time had little effect on RNA or DNA quality. Protein expression was assessed on tissue microarray by immunohistochemistry with antibodies against p53, WT1, E-cadherin, CK-7, and Ki67 from formalin fixed-paraffin embedded (FFPE) tissues. As seen with a nonhierarchical clustering statistical method, there was no significant difference in immunostaining of paraffin tissues among specimens from different biobanks. Interestingly, patients with worse outcome were highly positive for p53 and weak for WT1. In conclusion, while there was no common SOP for retrospectively collected material across Canadian biobanks, these results indicate that specimens collected at these multiple sites are of comparable quality, and can serve as an adequate resource to create a national cohort for the validation of molecular biomarkers in ovarian cancer.

Clinicopathological heterogeneity in ovarian clear cell adenocarcinoma: a study on individual therapy practice

Ovarian clear cell adenocarcinoma (CCA) has been believed to be a lethal histological subtype of an epithelial ovarian adenocarcinoma (EOA); its precursor has been assumed to be endometriosis. However, it has been reported that CCAs occasionally exhibit different clinical behaviors, suggesting that CCAs might not belong to a single category. We focused on CCAs combined with other histological types of EOAs; we re-evaluated the pathology of 46 CCAs and divided them into two subgroups: 35 CCAs alone (pure-type CCAs); and 11 CCAs with other histological types, endometrioid adenocarcinomas (EAs) or/and serous adenocarcinomas (SAs) (mixed-type CCAs). Immunohistochemical analysis for expression of ARID1A, p53, PTEN, Annexin 4, hepatocyte nuclear factor-1β (HNF-1β), and WT-1 was employed. We identified that patients with endometriosis were younger than those without endometriosis in pure-type CCAs (P < 0.005). In mixed-type CCAs, the immunohistochemical-staining patterns revealed internal transition of each histological component. In pure-type CCAs, expressions of ARID1A and p53 were mutually altered, and altered expression of p53 was associated with worse prognosis than that of ARID1A (P < 0.001). Our results provide evidence that CCAs would have clinicopathological heterogeneity, determining the patient's prognosis. Furthermore, immunohistochemical analysis may shed light on the selection of appropriate treatment, including chemotherapy.

Metastatic ovarian carcinoma to the brain: an approach to identification and classification for neuropathologists

Brain metastasis is an uncommon but increasing manifestation of ovarian epithelial carcinoma and neuropathologists' collective experience with these tumors is limited. We present clinicopathological characteristics of 13 cases of brain metastases from ovarian epithelial carcinoma diagnosed at two academic institutions. The mean ages at diagnosis of the ovarian carcinoma and their subsequent brain metastases were 58.7 and 62.8 years, respectively. At the time of initial diagnosis of ovarian carcinoma the majority of patients had an advanced stage and none had brain metastases as their first manifestation of malignancy. Brain metastases tended to be multiple with ring-enhancing features on neuroimaging. Primary tumors and their brain metastases were all high-grade histologically and the histologic subtypes were: nine high-grade serous carcinoma (HGSC) cases, two clear cell carcinoma (CCC) cases and a single case each of carcinosarcoma and high-grade adenocarcinoma. A recommended histo- and immunopathological approach to these tumours are provided to aid neuropathologists in the recognition and classification of metastatic ovarian carcinoma to the brain.

HNF-1β in ovarian carcinomas with serous and clear cell change

Many ovarian tumors, including high-grade serous carcinoma (HGSC), show clear cell change. Accurate diagnosis is important, however, as ovarian clear cell carcinoma (OCCC) is known to be less responsive to traditional types of ovarian cancer chemotherapies. In a previous study, the clinical, morphologic, and immunohistochemical features of 32 ovarian carcinomas, which had been previously diagnosed as pure OCCC (n=11), pure HGSC (n=11), and mixed serous and clear cell (MSC) (n=10), were analyzed. The immunoreactivities of WT1, ER, and p53, as well as the mitotic indices and stages of presentation of the MSC, were similar to those of HGSC. It was consequently concluded that MSC represented HGSC with clear cell change. Hepatocyte nuclear factor-1β (HNF-1β) is a relatively new immunohistochemical marker that has been shown to be rather sensitive and specific for OCCC. We thus sought to evaluate this marker in this specific group of tumors. One block each of pure HGSC and pure OCCC were stained with HNF-1β. In the cases of MSC, 2 blocks were stained when the serous and clear cell components were not present on the same slide. None (0/11) of the pure HGSC showed immunoreactivity for HNF-1β, whereas all (11/11) of the pure OCCC were positive. In the cases of MSC, both the serous and clear cell components were negative for HNF-1β. HNF-1β seems to be a sensitive and specific marker for OCCC and is not expressed in HGSC with clear cell change. The pattern of immunoreactivity of HNF-1β in tumors with both serous and clear cell change supports the conclusion that MSC are HGSC with clear cells.

Genome-wide association study of subtype-specific epithelial ovarian cancer risk alleles using pooled DNA

Epithelial ovarian cancer (EOC) is a heterogeneous cancer with both genetic and environmental risk factors. Variants influencing the risk of developing the less-common EOC subtypes have not been fully investigated. We performed a genome-wide association study (GWAS) of EOC according to subtype by pooling genomic DNA from 545 cases and 398 controls of European descent, and testing for allelic associations. We evaluated for replication 188 variants from the GWAS [56 variants for mucinous, 55 for endometrioid and clear cell, 53 for low-malignant potential (LMP) serous, and 24 for invasive serous EOC], selected using pre-defined criteria. Genotypes from 13,188 cases and 23,164 controls of European descent were used to perform unconditional logistic regression under the log-additive genetic model; odds ratios (OR) and 95 % confidence intervals are reported. Nine variants tagging six loci were associated with subtype-specific EOC risk at P < 0.05, and had an OR that agreed in direction of effect with the GWAS results. Several of these variants are in or near genes with a biological rationale for conferring EOC risk, including ZFP36L1 and RAD51B for mucinous EOC (rs17106154, OR = 1.17, P = 0.029, n = 1,483 cases), GRB10 for endometrioid and clear cell EOC (rs2190503, P = 0.014, n = 2,903 cases), and C22orf26/BPIL2 for LMP serous EOC (rs9609538, OR = 0.86, P = 0.0043, n = 892 cases). In analyses that included the 75 GWAS samples, the association between rs9609538 (OR = 0.84, P = 0.0007) and LMP serous EOC risk remained statistically significant at P < 0.0012 adjusted for multiple testing. Replication in additional samples will be important to verify these results for the less-common EOC subtypes.

Clear cell histology as a poor prognostic factor for advanced epithelial ovarian cancer: a single institutional case series through central pathologic review

Objective

Compared with serous adenocarcinoma (SAC), clear cell carcinoma (CCC) often shows chemo-resistance, which would potentially lead to a poor prognosis. On the other hand, there have been arguments over prognoses of CCC and SAC disease. In the present study, multivariate analysis to compare prognosis of CCC patients with that of SAC was aimed for the patients selected from central pathologic review.

Methods

Between 1984 and 2009, a total of 500 ovarian cancer patients were treated at our university hospital. Among them, 111 patients with CCC and 199 patients with SAC were identified through central pathological review. Overall survival and progression-free survival were compared using Kaplan-Meier method, and prognostic factors were investigated by multiple regression analyses.

Results

Median age was 52 years for CCC and 55 years for SAC (p=0.03). The ratio of stage I patients were significantly higher in CCC compared with SAC (55% vs. 13%, p<0.01). Among evaluable cases, response rate was significantly lower in CCC than that in SAC (32% vs. 78%, p<0.01). No significant differences of progression-free survival and overall survival were observed in stage I patients; however, prognoses of CCC were significantly poorer than those of SAC in advanced-stage disease. In stage II-IV patients, not only residual tumors and clinical stages, but also clear cell histology were identified as predictors for poor prognosis.

Conclusion

Clear cell histology was identified as a prognostic factor for advanced-stage ovarian cancers. Histologic subtypes should be considered in further clinical studies, especially for advanced epithelial ovarian cancers.

Architectural patterns of ovarian/pelvic high-grade serous carcinoma

We describe the architectural patterns of advanced ovarian/pelvic high-grade serous carcinomas that have been treated with upfront surgery, followed by adjuvant chemotherapy or neoadjuvant chemotherapy, followed by interval debulking to explore the association with the chemotherapeutic response. For 70 cases of advanced (i.e. stage III/IV) high-grade serous carcinomas (33 platinum resistant/intermediate, 37 platinum sensitive; 24 neoadjuvantly treated, 44 primary surgery), all tumor-containing histologic slides were reviewed by 1 of 3 pathologists. Histologic type was confirmed and the following features were assessed: major architectural pattern and the presence of any of 8 predefined minor architectural patterns (papillary, transitional cell carcinoma-like, micropapillary, microcystic, nested papillary, slit-like, glandular, solid). A semiquantitative assessment of psammoma bodies, histiocytic response, necrosis, nuclear atypia, and single-cell invasion was performed. Mitotic count was performed in 10 HPF and 1 HPF was counted for intraepithelial lymphocytes. The morphologic features were tested for an association with previous neoadjuvant chemotherapy and response to chemotherapy (resistant/intermediate versus chemotherapy-sensitive cases stratified by neoadjuvant chemotherapy), which was carried out using χ tests for categorical variables and analysis of variance for continuous data. Combinations of features were analyzed using unsupervised clustering (Wald). Although 8 of 18 features were significantly different when samples from neoadjuvantly treated patients were compared with those not previously treated, no individual histomorphologic feature or a combination of features was associated with response to chemotherapy. Further subtyping of high-grade serous carcinomas will likely need ancillary molecular markers that may have a greater potential to identify cases that will not respond to platinum-based chemotherapy.

Clear cell carcinoma of the female genital tract (not everything is as clear as it seems)

Clear cell carcinoma has a storied history in the female genital tract. From the initial designation of ovarian clear cell adenocarcinoma as "mesonephroma" to the linkage between vaginal clear cell carcinoma and diethylstilbestrol exposure in utero, gynecologic tract clear cell tumors have puzzled investigators, posed therapeutic dilemmas for oncologists, and otherwise presented major differential diagnostic challenges for pathologists. One of the most common errors in gynecologic pathology is misdiagnosis of clear cell carcinoma, on both frozen section and permanent section. Given the poor response to platinum-based chemotherapy for advanced-stage disease and increased risk of thromboembolism, accurate diagnosis of clear cell carcinoma is important in the female genital tract. This review (1) presents the clinical and pathologic features of female genital tract clear cell carcinomas; (2) highlights recent molecular developments; (3) identifies areas of potential diagnostic confusion; and (4) presents solutions for these diagnostic problems where they exist.

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.

BRCA mutation frequency and patterns of treatment response in BRCA mutation-positive women with ovarian cancer: a report from the Australian Ovarian Cancer Study Group

PURPOSE

The frequency of BRCA1 and BRCA2 germ-line mutations in women with ovarian cancer is unclear; reports vary from 3% to 27%. The impact of germ-line mutation on response requires further investigation to understand its impact on treatment planning and clinical trial design.

PATIENTS AND METHODS

Women with nonmucinous ovarian carcinoma (n = 1,001) enrolled onto a population-based, case-control study were screened for point mutations and large deletions in both genes. Survival outcomes and responses to multiple lines of chemotherapy were assessed.

RESULTS

Germ-line mutations were found in 14.1% of patients overall, including 16.6% of serous cancer patients (high-gradeserous, 17.1%); [corrected] 44% had no reported family history of breast orovarian cancer.Patients carrying germ-line mutations had improved rates of progression-free and overall survival. In the relapse setting, patients carrying mutations more frequently responded to both platin- and nonplatin-based regimens than mutation-negative patients, even in patients with early relapse after primary treatment. Mutation-negative patients who responded to multiple cycles of platin-based treatment were more likely to carry somatic BRCA1/2 mutations.

CONCLUSION

BRCA mutation status has a major influence on survival in ovarian cancer patients and should be an additional stratification factor in clinical trials. Treatment outcomes in BRCA1/2 carriers challenge conventional definitions of platin resistance, and mutation status may be able to contribute to decision making and systemic therapy selection in the relapse setting. Our data, together with the advent of poly(ADP-ribose) polymerase inhibitor trials, supports the recommendation that germ-line BRCA1/2 testing should be offered to all women diagnosed with nonmucinous, ovarian carcinoma, regardless of family history.

Clear cell carcinoma of the ovary: a review of the literature

OBJECTIVE

Different histologic types of epithelial ovarian cancer may represent different diseases with unique clinical and molecular characteristics. Clear cell carcinoma (CCC) of the ovary has been reported as having a worse prognosis than high grade serous epithelial ovarian cancer (EOC). This article critically reviews the literature pertinent to the pathology, pathogenesis, diagnosis, management, and outcome of patients with ovarian CCC.

METHODS

MEDLINE was searched for all research articles published in English between January 01, 1977 and January 30, 2012 which reported on patients diagnosed with ovarian CCC. Given the rarity of this tumor, studies were not limited by design or number of reported patients.

RESULTS

Ovarian CCC tumors represent 5-25% of ovarian cancers. Its histologic diagnosis can be challenging, resulting often times in misclassification of these tumors. Ovarian CCC tends to present at earlier stages and has been associated with endometriosis, ARID1A and PIK3CA mutations. When compared to stage-matched controls, patients with early-stage ovarian CCCs may have a better prognosis than patients with high-grade serous tumors. For those with advanced stage disease, high-grade serous histology confers a better prognosis than ovarian CCC. Patients with Stage IC-IV have a relatively poor prognosis and efforts should center in discovery of more effective treatment strategies.

CONCLUSIONS

Ovarian CCC is a biologically distinct entity, different from high-grade serous EOC. Future studies should explore the role of targeted therapies in the management of ovarian CCC.

Endometrial carcinomas: a review emphasizing overlapping and distinctive morphological and immunohistochemical features

This review focuses on the most common diagnostic pitfalls and helpful morphologic and immunohistochemical markers in the differential diagnosis between the different subtypes of endometrial carcinomas, including: (1) endometrioid versus serous glandular carcinoma, (2) papillary endometrioid (not otherwise specified, villoglandular and nonvillous variants) versus serous carcinoma, (3) endometrioid carcinoma with spindle cells, hyalinization, and heterologous components versus malignant mixed müllerian tumor, (4) high-grade endometrioid versus serous carcinoma, (5) high-grade endometrioid carcinoma versus dedifferentiated or undifferentiated carcinoma, (6) endometrioid carcinoma with clear cells versus clear cell carcinoma, (7) clear cell versus serous carcinoma, (8) undifferentiated versus neuroendocrine carcinoma, (9) carcinoma of mixed cell types versus carcinoma with ambiguous features or variant morphology, (10) Lynch syndrome-related endometrial carcinomas, (11) high-grade or undifferentiated carcinoma versus nonepithelial uterine tumors. As carcinomas in the endometrium are not always primary, this review also discusses the differential diagnosis between endometrial carcinomas and other gynecological malignancies such as endocervical (glandular) and ovarian/peritoneal serous carcinoma, as well as with extra-gynecologic metastases (mainly breast and colon).

Nonserous Ovarian Epithelial Tumors

This review covers the group of relatively uncommon nonserous ovarian epithelial tumors. The authors focus on the group's distinctiveness from the much more common serous tumors and show the similarities across entities. Diagnostic criteria that separate the different entities are currently being debated. Particular problems include the reproducible diagnosis of high-grade endometrioid, transitional cell, mixed epithelial and undifferentiated carcinomas. Furthermore, despite recognition that most malignant mucinous tumors involving ovary represent metastases from extraovarian primary sites, many misdiagnoses still occur. The authors discuss their rationale behind their opinions about these problematic topics.

High-Grade Serous Carcinoma Involving Fallopian Tube, Ovary and Peritoneum

The focus of this review is high-grade serous carcinoma (HGSC); for the purposes of this review, the term "pelvic SC" is used for HGSC that could be considered, based on historical definitions, to have arisen from ovary, fallopian tube, or peritoneum. These assignments of primary site are arbitrary and there is evidence that the distal fallopian tube is the site of origin of many pelvic HGSCs. The diagnosis of HGSC can be made readily based on routine histomorphologic examination in most cases; however, a variety of neoplasms can resemble HGSC. Thus, we review the key features of pelvic SC, current concepts of its pathogenesis, histopathological diagnostic criteria, discuss differential diagnosis, and review diagnostic ancillary studies that can be used in practice.

Benign and Low Grade Serous Epithelial Tumors: Recent Developments and Diagnostic Problems

This review focuses on recent advances in the area of low-grade ovarian serous neoplasia with emphasis on key diagnostic criteria, differential diagnosis, and disease classification based on current understanding of low-grade serous carcinogenesis. Despite considerable controversy surrounding serous tumors of low malignant potential (S-LMP) or borderline tumors, there have been great strides in our understanding of the serous group of borderline and malignant pelvic epithelial neoplasms in the past decade. Most S-LMP have a favorable prognosis, but recurrences and progression to carcinoma occur, sometimes following a protracted clinical course. Pathologic risk factors vary, but the extraovarian implant status is the most important predictor for progressive disease. Progression of S-LMP usually takes the form of low-grade serous carcinoma, although transformation to high-grade carcinoma is occasionally seen. A pelvic S-LMP - low-grade serous carcinoma pathway has been proposed based on global gene expression profiling, shared mutations in KRAS and/or BRAF, and in most cases, the presence of S-LMP in de novo low-grade serous carcinoma. Unlike high-grade serous carcinoma, low-grade serous carcinoma responds poorly to standard platinum-based chemotherapy. Development of more tailored therapy for S-LMP with invasive implants and low-grade serous carcinoma, ideally based on a relative risk model for disease progression, is under active clinical investigation.

Clear cell carcinoma of the ovary: a report from the first Ovarian Clear Cell Symposium, June 24th, 2010

OBJECTIVES

Recent literature has highlighted histological types of ovarian carcinoma as distinct diseases, each with unique clinical and molecular features. Historically, the diagnosis of ovarian clear cell carcinoma (CCC) has been of concern to both patients and physicians due to reports that CCC is associated with a worse prognosis than the more common serous type of ovarian carcinoma (HGSC). This review discusses the unique features of ovarian CCC.

METHODS

In June of 2010, a group of researchers and clinicians convened in Vancouver to review and discuss the clinical, pathological, molecular, and treatment-related features of CCC.

RESULTS

CCC is the second most common type of ovarian epithelial cancer, representing 5-25% of ovarian carcinomas. It is characterised by its association with endometriosis, and frequent mutations of ARID1A and PIK3CA. Low-stage CCC appears to have a better outcome than stage matched HGSC, while the opposite is true for high-stage disease, suggesting that the current standard treatments applied to HGSC are ineffective for CCC.

CONCLUSIONS

Ovarian CCC is highly distinct from HGSC, and a clearer understanding of the basic biology of this disease is needed. Alternative therapies should be explored: irradiation and targeting disease-specific molecular markers should be examined in greater detail. Finally, novel approaches to clinical trial design are needed due to the smaller numbers of patients affected.

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.