Ber-EP4 and anti-calretinin antibodies: a useful combination for differential diagnosis of various histological types of ovarian cancer cells and mesothelial cells

Identification of biomarkers for the diagnosis and targets for therapy in patients with clear cell ovarian cancer: a systematic literature review

Clear cell ovarian cancer (CCOC) is a rare type of epithelial cancer often resistant to platinum-based chemotherapy. Biomarkers for the diagnosis of CCOC, and targets for immunotherapy, both have the potential to improve outcomes for patients. Our review aims to determine whether any antigens already identified in the literature could fulfil this remit. PubMed, Medline, Web of Science, Scopus, Cochrane, CINAHL and EMBASE were searched and included all reported studies up until August 2021. Primary research articles on human adult females including at least 10 CCOC patients were included. Quality assurance was carried out using a modified version of the QUADAS-2 tool. Sensitivity, specificity and area under the curve were extracted from each included study by two independent reviewers. Twenty-three articles were included which identified 19 gene transcripts/proteins and one antibody, with reported sensitivities between 21% and 100% and specificities between 0% and 100% for expression in CCOC and differentiation from other epithelial ovarian cancer subtypes, benign gynaecological disease or normal tissue. Twelve studies identified biomarkers with a sensitivity and specificity above 80%. A panel of biomarkers consisting of IMP3, napsin A and hepatocyte nuclear factor 1 beta achieved the highest area under the curve of 0.954. This review demonstrates that there are promising candidate biomarkers for the diagnosis of CCOC, some of which are highly specific, and have the potential to act as targets for therapy. However, larger cohort studies are needed to validate these biomarkers and their potential use in clinical practice.

Malignant Mesothelioma of the Peritoneum in Women: A Clinicopathologic Study of 164 Cases

Malignant mesothelioma of the peritoneum in women is an uncommon tumor. In this study, we present the clinicopathologic features of 164 such cases seen in our institution over a period of 42 years (1974-2016). Clinical information, pathologic findings, immunohistochemical results, and follow-up were recorded. Hematoxylin and eosin-stained slides were reviewed in all cases. Patients ranged in age from 3 to 85 years, median: 49 years. Most patients presented with abdominal/pelvic pain, although some were asymptomatic, presented with paraneoplastic syndromes or cervical lymphadenopathy. Overall, 9% of patients had a history of direct or indirect exposure to asbestos. In total, 31% and 69% of patients had either a personal or family history of other tumors; most of these tumors are currently recognized as part of a syndrome. Genetic testing information was available in 5 patients: BAP-1 germline mutation (1), type 2 neurofibromatosis (1), Lynch syndrome (1), McCune-Albright syndrome (1), no BAP-1 or TP53 mutation (1). Most cases had gross and microscopic features typical of malignant mesothelioma of the peritoneum in women; however, some had confounding features such as gelatinous appearance, signet ring or clear cells, and well-differentiated papillary mesothelioma-like areas. Calretinin and WT-1 were the markers more frequently expressed, and up to 23% of the cases showed PAX-8 expression. Patients' treatments predominantly included: chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy. On multivariate analysis, the predominance of deciduoid cells, nuclear grade 3, and the absence of surgical treatment were associated with worse overall survival (OS). For all patients, the 3- and 5-year OS were 74.3% and 57.4%, respectively. The 3- and 5-year OS for patients treated with cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy were 88.9% and 77.8%, respectively.

Ber-EP4 staining in effusion cytology: A potential source of false positives

The distinction between reactive mesothelium and carcinoma in serous effusions can be very difficult. Immunocytochemistry (ICC) is the most widely used tool to improve the diagnostic accuracy of body fluid cytology, with several ICC markers being proposed. Ber-EP4 antibody has shown high sensitivity and specificity rates for diagnosing metastatic carcinoma. In our department, we have detected Ber-EP4 positivity in mesothelium in some cytological specimens. We reviewed all articles on Ber-EP4 staining in effusion cytology, summarized current findings and analyzed the staining pattern of all cases expressing Ber-EP4. Some cases showing Ber-EP4 positivity in mesothelium have been reported, most of which showed only weak Ber-EP4 staining or staining of less than 50% of mesothelial cells. However, some cases may show strong positivity both in cytological and histological specimens. Clinicians and pathologists should be aware of this source of misdiagnosis, and ICC results in mesothelium should be always interpreted cautiously and correlated with clinical tests, other ICC markers and patient's previous history.

Upregulation of mesothelial genes in ovarian carcinoma cells is associated with an unfavorable clinical outcome and the promotion of cancer cell adhesion

A hallmark of ovarian high‐grade serous carcinoma (HGSC) is its early and massive peritoneal dissemination via the peritoneal fluid. It is generally believed that tumor cells must breach the mesothelium of peritoneal organs to adhere to the underlying extracellular matrix (ECM) and initiate metastatic growth. However, the molecular mechanisms underlying these processes are only partially understood. Here, we have analyzed 52 matched samples of spheroids and solid tumor masses (suspected primary lesions and metastases) from 10 patients by targeted sequencing of 21 loci previously proposed as targets of HGSC driver mutations. This analysis revealed very similar patterns of genetic alterations in all samples. One exception was FAT3 with a strong enrichment of mutations in metastases compared with presumed primary lesions in two cases. FAT3 is a putative tumor suppressor gene that codes for an atypical cadherin, pointing a potential role in peritoneal dissemination in a subgroup of HGSC patients. By contrast, transcriptome data revealed clear and consistent differences between tumor cell spheroids from ascites and metastatic lesions, which were mirrored by the in vitro adherence of ascites‐derived spheroids. The adhesion‐induced transcriptional alterations in metastases and adherent cells resembled epithelial–mesenchymal transition, but surprisingly also included the upregulation of a specific subset of mesothelial genes, such as calretinin (CALB2) and podoplanin (PDPN). Consistent with this finding, calretinin staining was also observed in subsets of tumor cells in HGSC metastases, particularly at the invasive tumor edges. Intriguingly, a high expression of either CALB2 or PDPN was strongly associated with a poor clinical outcome. siRNA‐mediated CALB2 silencing triggered the detachment of adherent HGSC cells in vitro and inhibited the adhesion of detached HGSC cells to collagen type I. Our data suggest that the acquisition of a mesenchymal–mesothelial phenotype contributes to cancer cell adhesion to the ECM of peritoneal organs and HGSC progression.

Conversion of intraperitoneal cytology during laparoscopic surgery of uterine cancer

INTRODUCTION

The laparoscopic surgery of uterine cancer is an oncological safe treatment option in early stage cancer. However, there are no data about whether laparoscopy can lead to intraperitoneal tumor cell dissemination. We aimed in our study to detect a possible cytological conversion during laparoscopic procedures.

METHODS

In this prospective study, we included all patients receiving laparoscopic treatment at the early stage endometrial and cervical cancer in the Department of Obstetrics and Gynecology at the University of the Saarland and obtained peritoneal wash for cytological examination at the beginning and at the end of laparoscopic surgery. All patients received stage-adjusted operative and adjuvant therapy.

RESULTS

We enrolled 43 patients [endometrial cancer (n = 24) and cervical cancer (n = 19)]. At the beginning of the operation, one patient with endometrial cancer and one patient with cervical cancer showed a positive cytology. One tumor cell conversion from negative to positive cytology during surgery was detected in a patient suffering from endometrial cancer stage FIGO Ia. The median duration of surgery was 191.8 ± 79.3 min. The average time of follow-up was 16.5 ± 10.3 month. At the end of data evaluation at December 2014, two patients (8.6 %) are suffering from recurrent disease, two patients died, none of these patients had a positive cytology. All patients with positive cytology are free of cancer.

CONCLUSION

During laparoscopic surgery of early stage endometrial and cervical cancer, only one conversion of cytology was detected, which proves that laparoscopy does not appear to increase the intraoperative tumor cell dissemination or rate of positive cytological results.

Anticancer property of bromelain with therapeutic potential in malignant peritoneal mesothelioma

Bromelain is a mixture of proteolytic enzymes that is capable of hydrolyzing glycosidic linkages in glycoprotein. Glycoprotein's are ubiquitously distributed throughout the body and serve a variety of physiologic functions. Faulty glycosylation of proteins may lead to cancer. Antitumor properties of bromelain have been demonstrated in both, in vitro and in vivo studies, along with scanty anecdotal human studies. Various mechanistic pathways have been proposed to explain the anticancer properties of bromelain. However, proteolysis by bromelain has been suggested as a main pathway by some researchers. MUC1 is a glycoprotein that provides tumor cells with invasive, metastatic, and chemo-resistant properties. To date, there is no study that examines the effect of bromelain on MUC1. However, the viability of MUC1 expressing pancreatic and breast cancer cells are adversely affected by bromelain. Further, the efficacy of cisplatin and 5-FU are enhanced by adjuvant treatment with bromelain, indicating that the barrier function of MUC1 may be affected. Other studies have also indicated that there is a greater accumulation of 5-FU in the cell compartment on treatment with 5-FU and bromelain. Malignant peritoneal mesothelioma (MPM) expresses MUC1 and initial studies have shown that the viability of MPM cells is adversely affected by exposure to bromelain. Further, bromelain in combination with either 5-FU or cisplatin, the efficacy of the chemotherapeutic drug is enhanced. Hence, current evidence indicates that bromelain may have the potential of being developed into an effective anticancer agent for MPM.

Intra-abdominal hyaluronan concentration in peritoneal fluid of horses with sudden signs of severe abdominal pain

OBJECTIVE

To determine hyaluronan concentrations in peritoneal fluid from healthy horses and horses with sudden signs of severe abdominal pain and to identify the cellular sources of hyaluronan within the peritoneal cavity.

ANIMALS

7 client-owned horses that were evaluated for sudden signs of severe abdominal pain, 6 healthy teaching horses, and 13 euthanized horses (11 with no abdominal disease and 2 that had undergone abdominal surgery 2 weeks previously for a different study).

PROCEDURES

Abdominal fluid was collected from the client-owned and teaching horses. Hyaluronan concentrations were determined with an ELISA. Equine mesothelial cells were aseptically harvested from euthanized horses immediately after euthanasia, cultured, and processed for western blot immunoassays to detect expression of the following mesothelial cell markers: cytokeratins 8 and 18, vimentin, calretinin, mesothelin, and CD44. A reverse transcriptase-PCR assay was used to detect genetic expression of hyaluronan synthase-2 (HAS-2) from cultured and native equine tissue.

RESULTS

The mean ± SD abdominal hyaluronan concentration in peritoneal fluid from horses with signs of abdominal pain (1,203.3 ± 46.3 ng/mL) was significantly greater than that in healthy horses (228.4 ± 167.3 ng/mL). Harvested cells were maintained, and immunoblotting analyses confirmed expression of the mesothelial markers. Gene expression of HAS-2 from cultured mesothelial cells and fibroblasts was confirmed.

CONCLUSIONS AND CLINICAL RELEVANCE

Peritoneal hyaluronan concentration was much higher in horses with severe abdominal pain than in healthy horses. Cultured equine mesothelial cells and fibroblasts can produce hyaluronan through HAS-2. Future investigation should focus on establishing the effect of exogenous hyaluronan administration on mesothelial cell function in horses with abdominal disease.

Utility of paired box gene 8 (PAX8) expression in fluid and fine-needle aspiration cytology: an immunohistochemical study of metastatic ovarian serous carcinoma

BACKGROUND

Metastases from ovarian neoplasms are commonly encountered in peritoneal fluids. In addition, reactive mesothelial cells in effusion specimens can mimic ovarian serous carcinoma, making the diagnosis difficult. Calretinin has been recognized as a reliable immunohistochemical marker for mesothelial cells, whereas WT1 has proven useful in the diagnosis of ovarian serous carcinoma. This can present a diagnostic pitfall in effusion cytology, because mesothelial cells can demonstrate immunoreactivity for WT1. Recently, paired box gene 8 (PAX8) has been used in distinguishing ovarian from mammary carcinoma. To the authors' knowledge, no studies using PAX8 have been performed on peritoneal cytology specimens to date, and its expression in metastatic ovarian serous carcinoma has not been studied.

METHODS

These markers, along with BerEP4 and MOC-31, were evaluated in cytology cell block preparations from 30 fluid cytology specimens and 11 fine-needle aspiration specimens.

RESULTS

PAX8 was found to be positive in 37 of 41 (90%) ovarian carcinoma cases studied, and was a sensitive (90%) and specific (100%) marker for the detection of metastatic ovarian carcinoma. In addition, calretinin was found to be useful for identifying mesothelial cells in fluid cytology. Furthermore, although PAX8 and WT1 have demonstrated comparable sensitivity (90% and 93%, respectively) in diagnosing metastatic ovarian carcinoma, PAX8 appears to have superior specificity because staining is not observed in mesothelial cells. BerEP4 and MOC-31 were found to have a lower sensitivity and specificity compared with PAX8.

CONCLUSIONS

PAX8-positive, calretinin-negative staining appears to be highly specific and sensitive for detecting metastatic ovarian serous carcinoma in cytologic preparations and can be useful in distinguishing it from mesothelial cells in fluid cytology.

Catumaxomab--trifunctional anti-EpCAM antibody used to treat malignant ascites

IMPORTANCE OF THE FIELD

Malignant ascites is a sign of advanced tumour growth and is associated with significant morbidity and a poor prognosis with a median survival time of a few months. Paracentesis is a recommended treatment for malignant ascites, but can cause complications, for example infections, injury of abdominal organs, persistent leakage of ascites, and haematoma/haemorrhage. The European Medicines Agency (EMA) approved the use of a trifunctional bispecific antibody, catumaxomab (Removab), for the intraperitoneal (i.p.) treatment of malignant ascites in April 2009.

AREAS COVERED IN THIS REVIEW

This review describes the tailored preclinical and the clinical development of catumaxomab for the i.p. treatment of malignant ascites from 1998 to 2009.

WHAT THE READER WILL GAIN

Relevant toxicology and pharmacokinetic findings are reported as well as main results of a large international Phase II/III study that was pivotal in the EMA approval of catumaxomab.

TAKE HOME MESSAGE

Catumaxomab i.p. treatment results in a significant and clinically relevant improvement of puncture-free survival time and time to first need for puncture compared with paracentesis alone. The related side effects of catumaxomab treatment are predictable and related to the antibody's mode of action.

The trifunctional antibody catumaxomab for the treatment of malignant ascites due to epithelial cancer: Results of a prospective randomized phase II/III trial

Malignant ascites is a common manifestation of advanced cancers, and treatment options are limited. The trifunctional antibody catumaxomab (anti-epithelial cell-adhesion molecule x anti-CD3) represents a targeted immunotherapy for the intraperitoneal (i.p.) treatment of malignant ascites secondary to epithelial cancers. In this phase II/III trial (EudraCT 2004-000723-15; NCT00836654), cancer patients (n = 258) with recurrent symptomatic malignant ascites resistant to conventional chemotherapy were randomized to paracentesis plus catumaxomab (catumaxomab) or paracentesis alone (control) and stratified by cancer type (129 ovarian and 129 nonovarian). Catumaxomab was administered as an i.p. infusion on Days 0, 3, 7 and 10 at doses of 10, 20, 50 and 150 μg, respectively. The primary efficacy endpoint was puncture-free survival. Secondary efficacy parameters included time to next paracentesis, ascites signs and symptoms and overall survival (OS). Puncture-free survival was significantly longer in the catumaxomab group (median 46 days) than the control group (median 11 days) (hazard ratio = 0.254: p < 0.0001) as was median time to next paracentesis (77 versus 13 days; p < 0.0001). In addition, catumaxomab patients had fewer signs and symptoms of ascites than control patients. OS showed a positive trend for the catumaxomab group and, in a prospectively planned analysis, was significantly prolonged in patients with gastric cancer (n = 66; 71 versus 44 days; p = 0.0313). Although adverse events associated with catumaxomab were frequent, they were manageable, generally reversible and mainly related to its immunologic mode of action. Catumaxomab showed a clear clinical benefit in patients with malignant ascites secondary to epithelial cancers, especially gastric cancer, with an acceptable safety profile.

Challenges in the interpretation of peritoneal cytologic specimens

CONTEXT

The presence of malignant cells in peritoneal washings leads to classification as International Federation of Gynecology and Obstetrics stage IC or higher in ovarian carcinomas and at least International Federation of Gynecology and Obstetrics stage IIIA in endometrial carcinomas. Unfortunately, the morphologic examination of cytologic specimens has not proven to be a sensitive or specific diagnostic tool. Malignant cells might be few in number and might be unrecognized among a large population of mesothelial cells and/or macrophages, or reactive mesothelial cells might be misinterpreted as neoplastic cells leading to unnecessary chemotherapy.

OBJECTIVE

To evaluate the main pitfalls in the evaluation of peritoneal washings in patients with gynecologic malignancies and analyze the ancillary studies that might be helpful to achieve the correct diagnosis with an emphasis on immunocytochemistry.

DATA SOURCES

A comprehensive review of the literature was performed.

CONCLUSIONS

Peritoneal effusions may represent major challenges to the pathologist and can have important clinical implications. Immunostains for epithelial markers such as B72.3, MOC-31, and Ber-EP4 represent the best available markers to identify epithelial cells. Caution is advised to not overdiagnose endometriosis or endosalpingiosis as adenocarcinoma.

Calretinin: diagnostic utility in the female genital tract

The utility of calretinin was first described in the diagnosis of mesothelioma. In the female genital tract, calretinin was initially reported in Wolffian remnants and related lesions and later used in the diagnosis of sex cord stromal tumors of the ovary, endometrial stromal tumors with sex cord-like differentiation, and uterine tumors resembling sex cord tumors of the ovary. This review discusses calretinin expression in normal tissues of the female genital tract and highlights its potential utility in the diagnosis of these subsets of neoplasms with emphasis to tumors that may constitute a problem in their differential diagnosis. In particular, the limited utility of calretinin in the diagnosis of sex cord stromal tumors of the ovary, in the differential diagnosis between mesothelioma and serous tumors involving the ovary and/or peritoneum, and in the differential diagnosis between Wolffian lesions and endometrial carcinoma are addressed.

A novel technique for the enrichment of primary ovarian cancer cells

OBJECTIVE

Primary cancer cells that are extracted from ovarian tumors can serve as an optimal substrate to study the biologic characteristics of ovarian cancer. We describe an efficient and effective method of enriching ovarian tumor cells from ascitic fluid using an immunomagnetic-based method.

STUDY DESIGN

Mononuclear cells were isolated from ascites specimens by Ficoll gradient separation. Epithelial ovarian cancer cells were labeled magnetically with monoclonal human epithelial antigen-125 that is conjugated to microbeads. After immunomagnetic separation, the purity of tumor cells before and after purification was quantified by cytologic analysis and confirmed by fluorescence-activated cell sorter analysis.

RESULTS

Peritoneal ascites specimens were obtained from 6 patients with ovarian cancer. The median age of our patients was 61.5 years (range, 46-79 years). Three patients had papillary serous carcinoma; 2 patients had clear cell carcinoma, and 1 patient had an undifferentiated adenocarcinoma. The mean tumor purity was only 22.8% +/- 10% (range, 1%-60%) before separation. After enrichment, the purity improved to 82.3% +/- 4.0% (range, 70%-90%). Our enrichment technique increased the tumor purity by 59.5% +/- 8.4%. The mean percent yield after positive enrichment was 30.1% +/- 14.5%.

CONCLUSION

The immunomagnetic cell separation technique is an efficient and effective method for isolating and purifying ovarian tumor cells from ascites. Results from experiments with fresh tumor cells rather than cancer cell lines may be more relevant for clinical application.

Diagnostic accuracy of cytology and immunocytology in carcinomatous effusions

BACKGROUND

Immunocytology substantially improves the diagnostic accuracy of conventional cytology in the diagnosis of carcinomatous effusions. Due to the unequivocal characterization of the various cell populations, a sensitivity of 92% and specificity of 100% was achieved by immunocytology, examining samples of 1234 serous effusions.

OBJECTIVE

Cytology plays a central role in the aetiological clarification of serous effusions. The sensitivity of this method for the diagnosis of carcinomatous effusions varies between 40% and 80%. The aim of the present study was to investigate whether immunocytology substantially improves the diagnostic quality of the cytological examination in the diagnosis of carcinomatous effusions.

METHOD

Consecutive serous effusions were examined by conventional cytology and by immunocytology. The immunocytological examination was performed on smears, using a standard panel of three antibodies against pancytokeratin, human epithelial antigen 125 and calretinin.

RESULTS

Altogether, 1234 effusion samples were examined. A total of 603 effusions were caused by carcinomas, five by malignant mesotheliomas, 11 by malignant lymphomas and 615 by non-malignant disorders. In conventional cytology, carcinomatous effusions were correctly diagnosed in 314 samples, corresponding to a sensitivity of 52%. In 31 specimens (5%) tumour cells without further specification were described and in 161 samples (27%) the presence of tumour cells was suspected (84% overall sensitivity). A total of 97 carcinomatous effusions (16%) were diagnosed false-negatively and 50 (8%) of the 615 non-malignant effusions false-positively (92% specificity). In immunocytology, 561 carcinomatous samples were correctly diagnosed, representing a sensitivity of 93%. In six cases (1%) the presence of tumour cells was suspected. A total of 36 carcinomatous effusions (6%) were diagnosed false-negatively (94% over-all sensitivity). Out of the 615 non-malignant specimens, there were no false-positive diagnoses (100% specificity).

CONCLUSION

Immunocytology is a simple, cost-effective, routinely practicable method which substantially improves the diagnostic accuracy of conventional cytology in the diagnosis of carcinomatous effusions. Therefore, we recommend the use of immunocytology in all those cases where cytology on its own is not completely unequivocal.

Specific expression of hepatocyte nuclear factor-1beta in the ovarian clear cell adenocarcinoma and its application to cytological diagnosis

Ascitic cytological diagnosis is critical, but ovarian adenocarcinoma cells and reactive mesothelial cells can be difficult to distinguish because they usually have atypical cell nuclei and increased nuclear/cytoplasmic ratios. Previous studies using DNA microarrays have demonstrated that hepatocyte nuclear factor-1beta (HNF-1beta) is expressed specifically in clear cell adenocarcinoma (CCC). Thus, in the present study, we investigated the usefulness of HNF-1beta as an immunocytochemical diagnostic marker of CCC in ascitic specimens. We first confirmed that HNF-1beta expression levels were significantly higher in CCC than in non-CCC (i.e. serous adenocarcinoma, mucinous adenocarcinoma and endometrioid adenocarcinoma) in 55 surgical specimens at both the mRNA (P < 0.05) and protein (P < 0.05) levels by real-time polymerase chain reaction and immunohistochemistry, respectively. Immunocytochemistry of 60 cytological specimens showed significant positivity in CCC cases whereas all non-CCC cells, except for three endometrioid adenocaricnoma cases, and mesothelial cells in the background stained negatively for anti-HNF-1beta antibody (P < 0.05). The sensitivity and specificity were calculated to be 0.955 and 0.921, respectively. Immmunostaining patterns of HNF-1beta on cytological specimens were similar to those observed on histopathological ovarian specimens from the same patients. Double immunohistochemical staining using anti-HNF-1beta antibody and HBME-1, a mesothelium-specific monoclonal antibody, confirmed that anti-HNF-1beta antibody distinguished CCC cells and mesothelial cells. In conclusion, our findings indicate the specific expression of HNF-1beta in ovarian CCC and possible clinical applications of HNF-1beta immunocytochemical staining for the differential cytopathological diagnosis of CCC from non-CCC, as well as from mesothelial cells using cytological specimens from ovarian carcinoma patients.