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 (TILhigh) 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.

Time trends in the incidence of hysterectomy-corrected overall, type 1 and type 2 endometrial cancer in Denmark 1978-2014.

OBJECTIVE: To investigate time trends in the incidence of overall, type 1 and type 2 endometrial cancer in Denmark 1978-2014, correcting for hysterectomy. METHODS: Based on the Danish Cancer Registry and the Danish National Patient Registry we calculated hysterectomy-corrected incidence rates of overall, type 1 and type 2 endometrial cancer. Separate analyses for women <55years (defined as pre- and perimenopausal age) and women aged ≥55years (defined as postmenopausal age) and analyses allowing for different time trends before and after the study period midyear 1996 were performed. Log-linear Poisson models were used to estimate annual percentage change (APC) in incidence with 95% confidence intervals (CI). RESULTS: The overall incidence of endometrial cancer decreased slightly from 1978 to 1995, but in the last two decades of the study period the incidence has been stable (APC=0.16; 95% CI: -0.19; 0.50). In the study period (1978-2014) type 1 endometrial cancer incidence decreased slightly (APC=-0.67; 95% CI:-0.83; -0.52), whereas the incidence of type 2 endometrial cancer increased substantially (APC=4.85; 95% CI: 4.47; 5.23). The decrease in type 1 endometrial cancer was most pronounced before 1996 in women younger than 55 years (APC=-2.79; 95% CI: -3.65; -1.91), while the largest increase in type 2 endometrial cancer was observed after 1996 (APC=6.42; 95% CI: 5.72; 7.12). CONCLUSIONS: Over a period of more than 35 years, the incidence of type 1 endometrial cancer decreased, mainly in pre- and perimenopausal women, while type 2 endometrial cancer incidence increased.

[New features in the 2014 WHO classification of uterine neoplasms]. / Neues in der WHO-Klassifikation 2014 der Tumoren des Corpus uteri.

The 2014 World Health Organization (WHO) classification of uterine tumors revealed simplification of the classification by fusion of several entities and the introduction of novel entities. Among the multitude of alterations, the following are named: a simplified classification for precursor lesions of endometrial carcinoma now distinguishes between hyperplasia without atypia and atypical hyperplasia, the latter also known as endometrioid intraepithelial neoplasia (EIN). For endometrial carcinoma a differentiation is made between type 1 (endometrioid carcinoma with variants and mucinous carcinoma) and type 2 (serous and clear cell carcinoma). Besides a papillary architecture serous carcinomas may show solid and glandular features and TP53 immunohistochemistry with an "all or null pattern" assists in the diagnosis of serous carcinoma with ambiguous features. Neuroendocrine neoplasms are categorized in a similar way to the gastrointestinal tract into well differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas (small cell and large cell types). Leiomyosarcomas of the uterus are typically high grade and characterized by marked nuclear atypia and lively mitotic activity. Low grade stromal neoplasms frequently show gene fusions, such as JAZF1/SUZ12. High grade endometrial stromal sarcoma is newly defined by cyclin D1 overexpression and the presence of the fusion gene YWHAE/FAM22 and must be distinguished from undifferentiated uterine sarcoma. Carcinosarcomas (malignant mixed Mullerian tumors MMMT) show biological and molecular similarities to high-grade carcinomas.

Molecular classification of high grade endometrioid and clear cell ovarian cancer using TCGA gene expression signatures.

BACKGROUND: It is unclear whether the transcriptional subtypes of high grade serous ovarian cancer (HGSOC) apply to high grade clear cell (HGCCOC) or high grade endometrioid ovarian cancer (HGEOC). We aim to delineate transcriptional profiles of HGCCOCs and HGEOCs. METHODS: We used Agilent microarrays to determine gene expression profiles of 276 well annotated ovarian cancers (OCs) including 37 HGCCOCs and 66 HGEOCs. We excluded low grade OCs as these are known to be distinct molecular entities. We applied the prespecified TCGA and CLOVAR gene signatures using consensus non-negative matrix factorization (NMF). RESULTS: We confirm the presence of four TCGA transcriptional subtypes and their significant prognostic relevance (p<0.001) across all three histological subtypes (HGSOC, HGCCOC and HGEOCs). However, we also demonstrate that 22/37 (59%) HGCCOCs and 30/67 (45%) HGEOCs form 2 additional separate clusters with distinct gene signatures. Importantly, of the HGCCOC and HGEOCs that clustered separately 62% and 65% were early stage (FIGO I/II), respectively. These finding were confirmed using the reduced CLOVAR gene set for classification where most early stage HGCCOCs and HGEOCs formed a distinct cluster of their own. When restricting the analysis to the four TCGA signatures (ssGSEA or NMF with CLOVAR genes) most early stage HGCCOCs and HGEOC were assigned to the differentiated subtype. CONCLUSIONS: Using transcriptional profiling the current study suggests that HGCCOCs and HGEOCs of advanced stage group together with HGSOCs. However, HGCCOCs and HGEOCs of early disease stages may have distinct transcriptional signatures similar to those seen in their low grade counterparts.

The new WHO classification of ovarian, fallopian tube, and primary peritoneal cancer and its clinical implications.

INTRODUCTION: Molecular pathological research has contributed to improving the knowledge of different subtypes of ovarian cancer. In parallel with the implementation of the new FIGO staging classification, the WHO classification was revised. The latter is mainly based on the histopathological findings and defines the actual type of tumor. It has, therefore, also an important impact on prognosis and therapy of the patient. MATERIALS AND METHODS: The new WHO Classification of Ovarian Cancer published 2014 by Robert Kurman and co-authors is summarized. The major changes compared to the hitherto existing classification are presented. RESULTS: The new classification eliminates the previous focus of mesothelial origin of ovarian cancer. Instead, it features a discussion of tubal carcinogenesis of hereditary and some other high-grade serous carcinomas. The previously assumed pathogenesis pathway may be correct for some, but not for all, serous cancers. The new classification was established to classify ovarian cancer in a more consistent way. The earlier transitional cell type of ovarian cancer has been removed while seromucinous tumors have been added as a new entity. The role of some borderline tumors as one possible step in the progression from benign to invasive lesions is incorporated. The article summarizes the essential updates concerning serous, mucinous, seromucinous, endometrioid, clear-cell, and Brenner tumors. CONCLUSION: The new WHO classification takes into account the recent findings on the origin, pathogenesis, and prognosis of different ovarian cancer subtypes. The tubal origin of hereditary and some non-hereditary high-grade serous cancers is mentioned in contrast to the hitherto theory of mesothelial origin of tumors. Seromucinous tumors represent a new entity.

Low-Stage High-Grade Serous Ovarian Carcinomas: Support for an Extraovarian Origin.

Many adnexal high-grade serous carcinomas (HGSCs) may derive from microscopic precursors in the fallopian tube. By studying a series of low-stage ovarian carcinomas, we anticipated that HGSCs would be distributed in a pattern suggesting secondary involvement, helping to indirectly validate the fallopian tube origin theory, and that most ovarian carcinomas other than serous carcinomas would demonstrate features consistent with derivation from precursors located in or transplanted to the ovary. Seventy-six patients with low-stage (FIGO I/II) sporadic ovarian carcinoma who underwent primary surgical management at Memorial Sloan Kettering Cancer Center from 1980 to 2000 were included in the study. Histologic type was assigned using Gilks' criteria. Similar to the approach taken when distinguishing primary and metastatic mucinous or endometrioid carcinoma involving ovary, cases interpreted as showing a "primary" pattern of ovarian involvement had ≥3 of the following features: unilateral tumor, size >12 cm, no surface involvement, no multinodularity, and no destructive stromal invasion. All other cases were considered to show a "metastatic" pattern of ovarian involvement. Cases were evaluated for p53 and WT-1 expression, using standard techniques on a tissue microarray. TP53 gene sequencing was also performed. Cases comprised HGSC (n=22), endometrioid carcinoma (n=30), clear cell carcinoma (n=13), and mucinous carcinoma (n=11). HGSCs displayed substantially more "metastatic features" than the non-HGSC group and a mean overall size that was smaller (8.85 vs. 14.1 cm). Statistically significant differences were found for bilaterality (63% vs. 7.3%), P=0.0001; multinodularity (55% vs. 7.3%), P=0.0001; tumor size, P=0.003; and surface involvement (50% vs. 13%), P=0.002. Five of 22 (23%) of HGSCs showed a "primary pattern" of ovarian involvement. There were no significant differences between these cases and "metastatic pattern" HGSCs when comparing morphology, immunophenotype, TP53 mutational status, and clinical outcomes. Most low-stage HGSCs demonstrate patterns of ovarian involvement that suggest metastasis from another source, such as the fallopian tube. Both metastatic pattern HGSCs and unilateral, low-stage HGSCs can behave aggressively.

Molecular Alterations of TP53 are a Defining Feature of Ovarian High-Grade Serous Carcinoma: A Rereview of Cases Lacking TP53 Mutations in The Cancer Genome Atlas Ovarian Study.

The Cancer Genome Atlas has reported that 96% of ovarian high-grade serous carcinomas (HGSCs) have TP53 somatic mutations suggesting that mutation of this gene is a defining feature of this neoplasm. In the current study, 5 gynecologic pathologists independently evaluated hematoxylin and eosin slides of 14 available cases from The Cancer Genome Atlas classified as HGSC that lacked a TP53 mutation. The histologic diagnoses rendered by these pathologists and the accompanying molecular genetic data are the subject of this report. Only 1 case (Case 5), which contained a homozygous deletion of TP53, had unanimous interobserver agreement for a diagnosis of pure HGSC. In 1 case (Case 3), all 5 observers (100%) rendered a diagnosis of HGSC; however, 3 observers (60%) noted that the histologic features were not classic for HGSC and suggested this case may have arisen from a low-grade serous carcinoma (arisen from an alternate pathway compared with the usual HGSC). In 2 cases (Cases 4 and 12), only 3 observers (60%) in each case, respectively, interpreted it as having a component of HGSC. In the remaining 10 (71%) of tumors (Cases 1, 2, 6-11, 13, and 14), the consensus diagnosis was not HGSC, with individual diagnoses including low-grade serous carcinoma, high-grade endometrioid carcinoma, HGSC, metastatic carcinoma, clear cell carcinoma, atypical proliferative (borderline) serous tumor, and adenocarcinoma, not otherwise specified. Therefore, 13 (93%) of the tumors (Cases 1-4 and 6-14) were either not a pure HGSC or represented a diagnosis other than HGSC, all with molecular results not characteristic of HGSC. Accordingly, our review of the TP53 wild-type HGSCs reported in The Cancer Genome Atlas suggests that 100% of de novo HGSCs contain TP53 somatic mutations or deletions, with the exception of the rare HGSCs that develop from a low-grade serous tumor precursor. We, therefore, propose that lack of molecular alterations of TP53 are essentially inconsistent with the diagnosis of ovarian HGSC and that tumors diagnosed as such should be rigorously reassessed to achieve correct classification.

Are clear cell carcinomas of the ovary and endometrium phenotypically identical? A proteomic analysis.

Phenotypic differences between otherwise similar tumors arising from different gynecologic locations may be highly significant in understanding the underlying driver molecular events at each site and may potentially offer insights into differential responses to treatment. In this study, the authors sought to identify and quantify phenotypic differences between ovarian clear cell carcinoma (OCCC) and endometrial clear cell carcinoma (ECCC) using a proteomic approach. Tissue microarrays were constructed from tumor samples of 108 patients (54 ECCCs and 54 OCCCs). Formalin-fixed samples on microarray slides were analyzed by matrix-assisted laser desorption/ionization mass spectrometry, and 730 spectral peaks were generated from the combined data set. A linear mixed-effect model with random intercept was used to generate 93 (12.7%) peaks that were significantly different between OCCCs and ECCCs at the fold cutoffs of 1.5 and 0.667 and an adjusted P value cutoff of 1.0 × 10(-10). Liquid chromatography-tandem mass spectrometry was performed on selected cores from each group, and peptides identified therefrom were compared with lists of statistically significant peaks from the aforementioned linear mixed-effects model to find matches within 0.2 Da. A total of 53 candidate proteins were thus identified as being differentially expressed in OCCCs and ECCCs, 45 (85%) of which were expressed at higher levels in ECCCs than OCCCs. These proteins were functionally diverse and did not highlight a clearly dominant cellular theme or molecular pathway. Although ECCCs and OCCCs are very similar, some phenotypic differences are demonstrable. Additional studies of these differentially expressed proteins may ultimately clarify the significance of these differences.

Should All Cases of High-Grade Serous Ovarian, Tubal, and Primary Peritoneal Carcinomas Be Reclassified as Tubo-Ovarian Serous Carcinoma?

INTRODUCTION: The dualistic theory of ovarian carcinogenesis proposes that epithelial "ovarian" cancer is not one entity with several histological subtypes but a collection of different diseases arising from cells of different origin, some of which may not originate in the ovarian surface epithelium. METHODS: All cases referred to the Pan-Birmingham Gynaecological Cancer Centre with an ovarian, tubal, or primary peritoneal cancer between April 2006 and April 2012 were identified from the West Midlands Cancer Registry. Tumors were classified into type I (low-grade endometrioid, clear cell, mucinous, and low-grade serous) and type II (high-grade serous, high-grade endometrioid, carcinosarcoma, and undifferentiated) cancers. RESULTS: Ovarian (83.5%), tubal (4.3%), or primary peritoneal carcinoma (12.2%) were diagnosed in a total of 583 woman. The ovarian tumors were type I in 134 cases (27.5%), type II in 325 cases (66.7%), and contained elements of both type I and type II tumors in 28 cases (5.7%). Most tubal and primary peritoneal cases, however, were type II tumors: 24 (96.0%) and 64 (90.1%), respectively. Only 16 (5.8%) of the ovarian high-grade serous carcinomas were stage I at diagnosis, whereas 240 (86.6%) were stage III+. Overall survival varied between the subtypes when matched for stage. Stage III low-grade serous and high-grade serous carcinomas had a significantly better survival compared to clear cell and mucinous cases, P = 0.0134. There was no significant difference in overall survival between the high-grade serous ovarian, tubal, or peritoneal carcinomas when matched for stage (stage III, P = 0.3758; stage IV, P = 0.4820). CONCLUSIONS: Type II tumors are more common than type I and account for most tubal and peritoneal cancers. High-grade serous carcinomas, whether classified as ovarian/tubal/peritoneal, seem to behave as one disease entity with no significant difference in survival outcomes, therefore supporting the proposition of a separate classification of "tubo-ovarian serous carcinoma".

New insights in the pathophysiology of ovarian cancer and implications for screening and prevention.

Despite advances in medicine, ovarian cancer remains the deadliest of the gynecological malignancies. Herein we present the latest information on the pathophysiology of ovarian cancer and its significance for ovarian cancer screening and prevention. A new paradigm for ovarian cancer pathogenesis presupposes 2 distinct types of ovarian epithelial carcinoma with distinct molecular profiles: type I and type II carcinomas. Type I tumors include endometrioid, clear-cell carcinoma, and low-grade serous carcinoma and mostly arise via defined sequence either from endometriosis or from borderline serous tumors, mostly presenting in an early stage. More frequent type II carcinomas are usually high-grade serous tumors, and recent evidence suggests that the majority arise from the fimbriated end of the fallopian tube. Subsequently, high-grade serous carcinomas usually present at advanced stages, likely as a consequence of the rapid peritoneal seeding from the open ends of the fallopian tubes. On the other hand, careful clinical evaluation should be performed along with risk stratification and targeted treatment of women with premalignant conditions leading to type I cancers, most notably endometriosis and endometriomas. Although the chance of malignant transformation is low, an understanding of this link offers a possibility of prevention and early intervention. This new evidence explains difficulties in ovarian cancer screening and helps in forming new recommendations for ovarian cancer risk evaluation and prophylactic treatments.

Should endometrial clear cell carcinoma be classified as Type II endometrial carcinoma?

Endometrial clear cell carcinomas (ECCCs) are considered to be Type II endometrial carcinomas, like uterine serous adenocarcinoma (SCA), and therefore aggressive clinical management is indicated. However, according to the limited clinical, immunohistochemical, and molecular data available in the literature, ECCCs show overlapping features of SCA and endometrioid adenocarcinomas. Therefore, questions regarding their designation as the Type II carcinomas have been raised. We performed immunohistochemical staining for hepatocyte nuclear factor-1ß and napsin A for the histologic confirmation of clear cell carcinoma (CCC), and analyzed immunohistochemical findings for estrogen receptor, progesterone receptor, HER2/neu, p53, p16, ARID1A, PTEN, DNA mismatch-repair proteins along with other prognostic factors. We performed DNA sequencing for the K-RAS, BRAF, PIK3CA, and PTEN genes for 16 pure CCCs. No patients with pure CCC experienced recurrent disease or died of the disease (0/16, 0%). ECCCs had SCA-like features with rare expression of estrogen receptor/progesterone receptor (18.8%/6.3%) and no K-RAS mutations, intermediate features regarding expressions of p53 (37.5%) and p16 (25%), and endometrioid adenocarcinoma-like features regarding losses of PTEN (81.3%), ARID1A (25%) and mismatch-repair protein (68.8%), expression of microsatellite instability-high (25%), HER2/neu (12.5%), and PIK3CA mutations (18.8%). Pure ECCC should not be regarded as Type II carcinoma, because it shares the immunohistochemical and molecular characteristics of Type I endometrioid adenocarcinoma and Type II SCA.

Dualistic classification of epithelial ovarian cancer: surgical and survival outcomes in a large retrospective series.

BACKGROUND: Ovarian cancers have been recently categorized into types I and II according to a dualistic model of tumorigenesis. Data on the correlation between this classification and clinical outcome are still scarce and controversial. METHODS: A retrospective analysis of patients with ovarian cancer treated from 1998 to 2013 and operated by the same surgeon was conducted. Patients were classified into two groups: type I (125 patients), including low-grade serous, mucinous, endometrioid, and clear cell tumors; and type II (286 patients), including high-grade serous tumors, unspecified adenocarcinomas, and undifferentiated carcinomas. RESULTS: Type II patients had a significantly higher incidence of advanced disease than type I (88.4 vs. 65.6 %, P = 0.0001) and required more aggressive surgical procedures. Rates of optimal tumor debulking were almost similar between groups (92.6 vs. 91.7 %, type I vs. II, P = NS). After a median follow-up of 41 months, 207 patients (50.4 %) were alive and 204 (49.6 %) were dead; 79 type I patients (63.8 %) and 237 type II patients (82.7 %) experienced relapse (P = 0.02). Progression-free survival was significantly different between groups: 25 months for type I vs. 17 months for type II (P = 0.023). Overall survival was not significantly different between groups, with a median overall survival of 75 months for type I vs. 62 months for type II (P = 0.116). CONCLUSIONS: The dualistic histotype-based classification into types I and II of ovarian cancer does not seem to correlate with prognosis. Different molecular characteristics of type I and II tumors may have therapeutic implications and should be deeply investigated.

A suggested modification to FIGO stage I endometrial cancer.

OBJECTIVE: FIGO stage I endometrial cancers are divided into two substages, regardless of the presence or absence of lymphovascular space invasion (LVSI). The aim of this study was to investigate whether stratification based on the LVSI status would better predict mortality. METHODS: Using a multicentric database, we identified patients who underwent endometrial cancer operations between 2000 and 2010. The staging performance was quantified with respect to discrimination. RESULTS: The study cohort included 508 patients (198 with LVSI-positive tumors and 310 with LVSI-negative tumors). The survival difference between the stage I patients with LVSI-positive and LVSI-negative tumors was highly significant (81% and 97%, respectively P=.009), whereas the difference between the stage I patients with tumors invading greater or less than half of the myometrium was not (87% and 96%, respectively P=0.09). The 5-year OS rates for the patients with LVSI-negative tumors invading less than half of the myometrium, with LVSI-negative tumors invading more than half of the myometrium and with LVSI-positive invading more than or less than half of the myometrium were 98%, 95%, and 81%, respectively (P=.03). Separating the LVSI-negative and LVSI-positive tumors would improve discrimination (concordance index, 77% vs. 75%, respectively, using the actual staging system). CONCLUSION: A LVSI-positive status has a significantly worse prognosis. In this study, the distinction by LVSI status appears to be more relevant than the distinction between stages IA and IB for predicting survival in stage I endometrial cancer. This difference in prognosis would favor restaging these two entities.

Immunohistochemical and molecular characterization of clear cell carcinoma of the lung.

The diagnostic entity of clear cell carcinoma of the lung (CCCL) is controversial, with many investigators arguing against its inclusion in the World Health Organization classification of lung carcinoma. Because of its rarity and questions regarding its histogenesis, I studied 3 groups of carcinomas with immunohistochemical and molecular assays, including 6 cases of CCCL, 7 cases of adenocarcinoma with clear cell change, and 11 cases of squamous carcinomas with prominent clear cell change. CCCL tended to be present in older individuals with an adenocarcinoma immunophenotype (cytokeratin 7 and TTF1 positivity). Molecular analysis by Sanger sequencing revealed KRAS mutations in 5 of 6 cases of CCCL, 2 of 7 adenocarcinomas with clear cell change, and 2 of 11 squamous carcinomas with clear cell change. Although perhaps not a distinct pathologic entity, in this pilot study, CCCL has an immunophenotype similar to solid-type adenocarcinoma with clear cell change and displays more frequent and unusual KRAS mutations than expected in most adenocarcinomas of the lung.

What the EWSR1-ATF1 fusion has taught us about hyalinizing clear cell carcinoma.

Hyalinizing clear cell carcinoma (HCCC) is a unique low-grade tumor composed of cords and nests of clear cells in a hyalinized stroma that was first reported by Milchgrub et al. It was recognized as a separate entity from clear cell variants of epithelial-myoepithelial carcinoma, myoepithelial carcinoma and mucoepidermoid carcinoma. HCCC is included in a long list of clear cell-containing tumors of salivary gland, as well as odontogenic tumors and metastases (renal cell carcinoma). Up until now, it has been considered a diagnosis of exclusion, despite its very distinctive appearance, and labeled as "not otherwise specified" by the World Health Organization. The emergence of molecular data in salivary gland tumors, including HCCC now allow for a more rigorous appraisal of its spectrum. The EWSR1-ATF1 fusion has proven the concept of a "mucinous HCCC" and removes mucin as an exclusion criterion for this tumor. It has also proven a genetic link between clear cell odontogenic carcinoma and HCCC. Molecularly-proven cases have also highlighted variant morphologies and shown that cases with overt squamous differentiation are true HCCC. This gives further weight to the classification of this tumor as squamous or adenosquamous in differentiation and as a specific entity rather than an "NOS" tumor.