An allelotype analysis indicating the presence of two distinct ovarian clear-cell carcinogenic pathways: endometriosis-associated pathway vs. clear-cell adenofibroma-associated pathway

Endometriosis, a common but enigmatic disease with many faces: current concept of pathophysiology, and diagnostic strategy

Endometriosis is a benign, common, but controversial disease due to its enigmatic etiopathogenesis and biological behavior. Recent studies suggest multiple genetic, and environmental factors may affect its onset and development. Genomic analysis revealed the presence of cancer-associated gene mutations, which may reflect the neoplastic aspect of endometriosis. The management has changed dramatically with the development of fertility-preserving, minimally invasive therapies. Diagnostic strategies based on these recent basic and clinical findings are reviewed. With a focus on the presentation of clinical cases, we discuss the imaging manifestations of endometriomas, deep endometriosis, less common site and rare site endometriosis, various complications, endometriosis-associated tumor-like lesions, and malignant transformation, with pathophysiologic conditions.

Clear cell carcinoma of the ovary: Clues for radiologists to perform a correct diagnosis

Ovarian clear cell carcinoma (OCCC) is an uncommon high-grade primary epithelial ovarian cancer, covering about 10-12 % of all ovarian malignancies. It has a strong association with endometriosis. OCCC diagnosis, at advanced stages, has an aggressive biological behaviour, and the therapeutic strategies for ovarian OCCC are somehow different from other ovarian carcinomas. Therefore, early diagnosis of these tumours is of extreme importance. As some ovarian tumours subtypes have distinguishing features, it is possible to differentiate them based on their imaging characteristics, which can guide patient management and help the clinicians and pathologists in their diagnosis. A large mass on one side of the ovary that is mostly cystic, with a focal or multifocal irregular eccentric growing solid mural nodules or projections protruding into the cystic space, may suggest clear cell carcinoma of the ovary diagnosis. The solid nodules usually have an intermediate signal on T2-weighted images. The cystic component can be either single or multilocular, and the contents may contain protein or blood. CT scanning is still the preferred method for preoperative staging and postoperative restaging, and radiologists are crucial in identifying this type of tumour. We reviewed the imaging files of patients with surgically proven clear cell carcinoma at the specimens, and our findings agree with previous studies. This paper aims to perform a comprehensive revision of OCCC's radiological and clinic-pathological features and assist radiologists in recognizing OCCC and narrowing down the possibilities of differential diagnosis.

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.

Potential Coagulation Factor-Driven Pro-Inflammatory Responses in Ovarian Cancer Tissues Associated with Insufficient O₂ and Plasma Supply

Tissue factor (TF) is a cell surface receptor for coagulation factor VII (fVII). The TF-activated fVII (fVIIa) complex is an essential initiator of the extrinsic blood coagulation process. Interactions between cancer cells and immune cells via coagulation factors and adhesion molecules can promote progression of cancer, including epithelial ovarian cancer (EOC). This process is not necessarily advantageous, as tumor tissues generally undergo hypoxia due to aberrant vasculature, followed by reduced access to plasma components such as coagulation factors. However, hypoxia can activate TF expression. Expression of fVII, intercellular adhesion molecule-1 (ICAM-1), and multiple pro-inflammatory cytokines can be synergistically induced in EOC cells in response to hypoxia along with serum deprivation. Thus, pro-inflammatory responses associated with the TF-fVIIa-ICAM-1 interaction are expected within hypoxic tissues. Tumor tissue consists of multiple components such as stromal cells, interstitial fluid, albumin, and other micro-factors such as proton and metal ions. These factors, together with metabolism reprogramming in response to hypoxia and followed by functional modification of TF, may contribute to coagulation factor-driven inflammatory responses in EOC tissues. The aim of this review was to describe potential coagulation factor-driven inflammatory responses in hypoxic EOC tissues. Arguments were extended to clinical issues targeting this characteristic tumor environment.

Clear cell carcinoma of the ovary: comparison of MR findings of histological subtypes

PURPOSE

To retrospectively compare the MR findings of histological subtypes of clear cell carcinomas (CCCs) of the ovary.

MATERIALS AND METHODS

This single-center retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Between April 2005 and August 2015, we found 51 consecutive patients with histopathologically proven CCCs. Among them, 44 CCCs in 37 patients who underwent preoperative MR imaging were included. CCCs were pathologically divided into three subgroups: (1) four clear cell adenofibroma-associated CCCs, (2) 21 endometriosis-associated CCCs, and (3) 19 indeterminate CCCs. The statistical tests were used to compare the frequency of qualitative assessments and value of quantitative measurements among the histological subtypes.

RESULTS

On T2-weighted images, hypointense areas within solid components were more frequently observed in clear cell adenofibroma-associated CCCs [3/4 (75%)] than in the remaining CCCs [1/40 (3%)] (p < 0.01), and the signal intensity ratios (SIRs) of solid components were significantly lower in clear cell adenofibroma-associated CCCs (0.27 ± 0.13) than in the remaining CCCs (0.61 ± 0.18) (p < 0.01). On T1-weighted images, hyperintensities of cystic components were more frequently observed in the endometriosis-associated CCCs [17/21 (81%)] than in the remaining CCCs [5/20 (25%)] (p < 0.01), and the SIRs of cystic components were significantly higher in endometriosis-associated CCCs (2.99 ± 1.51) than in the remaining CCCs (1.82 ± 1.10) (p < 0.01).

CONCLUSION

MR features may help differentiate between adenofibroma-associated and endometriosis-associated CCC.

ARID1A expression in ovarian clear cell carcinoma with an adenofibromatous component

AIMS

The carcinogenesis of ovarian clear cell carcinoma (CCC) has been hypothesized to comprise two different pathways: an adenofibroma-carcinoma sequence and an endometriosis-carcinoma sequence. However, the difference in the genetic basis of these two pathways remains unclear. Recent studies have suggested that an ARID1A mutation and the loss of the corresponding protein, BAF250a, are frequent events in CCC. Herein, we investigated the difference in the loss of BAF250a expression in adenofibroma-related CCC and endometriosis-related CCC.

METHODS AND RESULTS

In total, 93 cases of surgically treated CCC were evaluated. The presence of adenofibroma and endometriosis associated with carcinoma was determined by reviewing haematoxylin and eosin-stained slides for each case. BAF250a expression in carcinoma was examined immunohistochemically. The loss of BAF250a expression was detected in carcinomas in 50 of 93 (54%) cases, including five of 18 (28%) with adenofibroma alone, 30 of 45 (67%) with endometriosis alone, eight of 18 (44%) with both conditions and seven of 12 (58%) with neither condition. The loss of BAF250a expression was significantly less frequent in CCC cases with adenofibroma than in cases with endometriosis (P = 0.01, Fisher's exact test).

CONCLUSIONS

The action of ARID1A in carcinogenesis differs between adenofibroma-related CCC and endometriosis-related CCC.

Gene amplification and protein overexpression of MET are common events in ovarian clear-cell adenocarcinoma: their roles in tumor progression and prognostication of the patient

The aim of this study was to assess protein overexpression and gene copy number alterations of MET in ovarian clear-cell adenocarcinoma, and to assess its potential as a novel therapeutic target. Ninety cases of clear-cell adenocarcinoma were analyzed for MET protein overexpression and copy number alterations of the MET gene by immunohistochemistry and brightfield double in situ hybridization, respectively. In addition, 101 cases of the non-clear-cell type ovarian carcinomas at advanced stages were also evaluated for comparison. MET overexpression was assigned when complete membrane staining with moderate or strong intensity was observed in at least 10% of the tumor cells examined. Double in situ hybridization was determined as positive when the tumor exhibited high-level polysomy (≥4 copies in ≥40% of tumor cells) or MET gene amplification. MET overexpression was detected in 20 of 90 clear-cell adenocarcinomas (22%) and none of 111 non-clear-cell type ovarian carcinomas. Double in situ hybridization was positive in 21 of 89 informative clear-cell adenocarcinomas (24%) and only 3 non-clear-cell type ovarian carcinomas (3%). In the whole population, true amplification of the MET gene was detected only in the clear-cell adenocarcinoma histology (five cases, 6%). In clear-cell adenocarcinomas, double in situ hybridization positivity was highly correlated with the presence of MET overexpression and a poorly differentiated histology of tumors (P=0.0105 and 0.00038, respectively). For the patients with clear-cell adenocarcinomas, MET overexpression, as well as advanced clinical stage and the poorly differentiated histology of tumors, was identified as an independent unfavorable prognostic factor for overall survival. In conclusion, among ovarian carcinomas, the amplification of the MET proto-oncogene is highly selective and commonly occurs in clear-cell adenocarcinoma. MET could serve as a biomarker for the prognostication of patients with clear-cell adenocarcinoma and tumor progression, and has potential as a novel therapeutic target for this carcinoma.

Borderline clear cell adenofibroma with extensive hemorrhagic necrosis

Borderline clear cell adenofibroma of the ovary is rather rare since most of clear cell tumors are carcinomas. We report a case of ovarian borderline clear cell adenofibroma in a 52-year-old postmenopausal woman. The tumor had the characteristic histologic features of borderline clear cell adenofibroma except for central extensive hemorrhagic necrosis. The prognosis of borderline clear cell adenofibroma is excellent. Because the invasiveness cannot be assessed in the necrotic areas, our patient needed long-term follow-up.

Pathogenesis of ovarian clear cell adenofibroma, atypical proliferative (borderline) tumor, and carcinoma: clinicopathologic features of tumors with endometriosis or adenofibromatous components support two related pathways of tumor development

The clinicopathologic features of 472 ovarian epithelial clear cell neoplasms (4 adenofibromas [AFs], 41 atypical proliferative [borderline] tumors [APTs], and 427 carcinomas [CAs]) were studied in order to elucidate the morphologic steps involved in the pathogenesis of these tumors and determine whether clear cell CA is a type I or type II tumor in the dualistic model of ovarian carcinogenesis. Thirty-three percent of the CAs had an adenofibromatous background [CA(AF+)], and 67% did not [CA(AF-)]. Endometriosis was found in all types of tumors, but tumors arising in endometriotic cysts were more frequent with CA(AF-)s (p<0.0001). The subset of women with CA(AF-)s with endometriosis were younger (p<0.0001), their tumors were more frequently cystic (p<0.0001), they more commonly had a mixed carcinoma component of non-clear cell type (p=0.006), and they were more frequently oxyphilic (p=0.015) compared with CA(AF+)s. The architecture of the former tumors was more commonly papillary compared to tubulocystic in the latter (p=0.0006). Atypical endometriosis was more common in CA(AF-)s than in AFs, APTs, and CC(AF+)s [p=0.004]. The subset of CA(AF-)s without endometriosis presented more frequently in advanced stage (>I) and were higher grade compared to CA(AF+)s or CA(AF-) with endometriosis (p-values, <0.0001 to 0.0071). All AFs and APTs were stage I compared to 79% of CA(AF+)s. An increase in mean tumor size correlated with each respective tumor category from AF (6.8 cm) to CA(AF+) [12.9 cm]. Notable nuclear atypia was absent in all AFs but was focally present in 27% of APTs and in the adenofibromatous background of 24% of the CA(AF+)s. An increase in the proportion of carcinoma in the CA(AF+)s correlated with an increase in grade and advanced stage. In summary, ovarian clear cell CA appears to develop along two pathways, both of which are related to endometriosis. We speculate that, in one, epithelial atypia arises in an endometriotic cyst and then evolves into clear cell CA, and, in the other, non-cystic endometriosis induces a fibromatous reaction resulting in the formation of AF, which then develops into APT and subsequently a clear cell CA. The absence of endometriosis or adenofibromatous components in CC(AF-)s may be due to overgrowth and obliteration by the invasive carcinoma. Finally, the findings in this study support the view that both types of clear cell CA [CC(AF+) and CC(AF-)] are more closely related to type I tumors.

Sorafenib efficacy in ovarian clear cell carcinoma revealed by transcriptome profiling

The purpose of this study was to investigate a new modality of therapy against ovarian clear cell carcinoma (OCCC), a chemoresistant subtype of ovarian cancer. Microarray datasets of ovarian cancer cell lines and cancer tissues were analyzed using bioinformatic tools. The gene expression profile of OCCC was similar to that of renal cell carcinoma (RCC). This similarity was at least partially due to hepatocyte nuclear factor 1 pathway activation common to both malignancies. In addition, oncogenic pathway alterations were characteristic of OCCC including hypoxia inducible factor 1 alpha subunit and relatively high Ras activities. Therefore, we predicted that the multi-kinase inhibitor sorafenib, which is approved for RCC and suppresses Ras activity, would also be effective against OCCC. Orally administered sorafenib (40 mg/kg per day) significantly inhibited tumor growth in nude mice when it was given after inoculation with the OCCC cell line RMG-2 (P = 0.002). Furthermore, sorafenib significantly reduced tumor size when it was administered to established RMG-2 tumors (P = 0.0002), while intraperitoneal injection of cisplatin (5 mg/kg per week) did not. In conclusion, the prominent anti-tumor effect of sorafenib against OCCC indicates that sorafenib is a promising candidate drug and supports the need for clinical trials using sorafenib against OCCC. This report demonstrates a method to utilize genome-wide information to facilitate translational research for treatments against less common subtypes of cancers.

Ovarian clear cell adenofibromatous tumor of borderline malignancy associated with high levels of carbohydrate antigen 19-9

This report presents a case of ovarian clear cell adenofibromatous tumor of borderline malignancy, which is a rare variant of an ovarian epithelial tumor associated with high levels of carbohydrate antigen 19-9 (CA19-9). A 79-year-old female with a large pelvic tumor underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy; her pre-operative serum CA19-9 level was 780 IU/mL. The diameter of the elastic hard ovarian tumor was 17 cm. Microscopically, many tubular glands lay in an abundant fibrocollagenous stroma. Most of the glands were lined with flattened cells or cuboidal clear cells with large nuclei, but in a small area there were small crowded glands. The epithelium of the glands, in which stratification occurred over three layers, had clear cytoplasmic regions and enlarged nuclei with prominent nucleoli. CA19-9 was immunohistochemically positive in the epithelial cells. The final diagnosis was ovarian clear cell adenofibromatous tumor of borderline malignancy, stage Ia. Postoperatively, her serum CA19-9 level decreased to the normal limit.