BAP1 and Claudin-4, But Not MTAP, Reliably Distinguish Borderline and Low-grade Serous Ovarian Tumors From Peritoneal Mesothelioma

Mapping and visualization of global research progress on deubiquitinases in ovarian cancer: a bibliometric analysis

Background

Ovarian cancer is a highly aggressive malignancy with limited therapeutic options and a poor prognosis. Deubiquitinating enzymes (DUBs) have emerged as critical regulators of protein ubiquitination and proteasomal degradation, influencing various cellular processes relevant to cancer pathogenesis. In this study, the research progress between ovarian cancer and DUBs was mapped and visualized using bibliometrics, and the expression patterns and biological roles of DUBs in ovarian cancer were summarized.

Methods

Studies related to DUBs in ovarian cancer were extracted from the Web of Science Core Collection (WoSCC) database. VOSviewer 1.6.20, CiteSpace 6.3.R1, and R4.3.3 were used for bibliometric analysis and visualization.

Results

For analysis 243 articles were included in this study. The number of publications on DUBs in ovarian cancer has gradually increased each year. China, the United States, and the United Kingdom are at the center of this field of research. The Johns Hopkins University, Genentech, and Roche Holding are the main research institutions. David Komander, Zhihua Liu, and Richard Roden are the top authors in this field. The top five journals with the largest publication volumes in this field are Biochemical and Biophysical Research Communications, Journal of Biological Chemistry, PLOS One, Nature Communications, and Oncotarget. Keyword burst analysis identified five research areas: "deubiquitinating enzyme," "expression," "activation," "degradation," and "ubiquitin." In addition, we summarized the expression profiles and biological roles of DUBs in ovarian cancer, highlighting their roles in tumor initiation, growth, chemoresistance, and metastasis.

Conclusion

An overview of the research progress is provided in this study on DUBs in ovarian cancer over the last three decades. It offers insight into the most cited papers and authors, core journals, and identified new trends.

Molecular and Immunohistochemical Testing in Mesothelioma and Other Mesothelial Lesions

CONTEXT.—

Molecular testing has increasingly been utilized in the evaluation of mesothelioma. Diffuse mesothelioma comprises multiple distinct genetic subgroups. While most diffuse mesotheliomas lack oncogenic kinase mutations and instead harbor alterations involving tumor suppressors and chromatin regulators, a minor subset of tumors is characterized by uncommon alterations such as germline mutations, genomic near-haploidization, ALK rearrangement, ATF1 rearrangement, or EWSR1::YY1 fusion.

OBJECTIVE.—

To provide updates on the salient molecular features of diffuse mesothelioma, mesothelioma in situ, and other mesothelial lesions: well-differentiated papillary mesothelial tumor, adenomatoid tumor, peritoneal inclusion cyst, and others. We consider the diagnostic, prognostic, and predictive utility of molecular testing in mesothelial lesions.

DATA SOURCES.—

We performed a literature review of recently described genetic features, molecular approaches, and immunohistochemical tools, including BAP1, MTAP, and merlin in mesothelioma and other mesothelial lesions.

CONCLUSIONS.—

Our evolving understanding of the molecular diversity of diffuse mesothelioma and other mesothelial lesions has led to considerable changes in pathology diagnostic practice, including the application of immunohistochemical markers such as BAP1, MTAP, and merlin (NF2), which are surrogates of mutation status. In young patients and/or those without significant asbestos exposure, unusual mesothelioma genetics such as germline mutations, ALK rearrangement, and ATF1 rearrangement should be considered.

Claudins in Cancer: A Current and Future Therapeutic Target

Claudins are a family of 27 proteins that have an important role in the formation of tight junctions. They also have an important function in ion exchange, cell mobility, and the epithelial-to-mesenchymal transition, the latter being very important in cancer invasion and metastasis. Therapeutic targeting of claudins has been investigated to improve cancer outcomes. Recent evidence shows improved outcomes when combining monoclonal antibodies against claudin 18.2 with chemotherapy for patients with gastroesophageal junction cancer. Currently, chimeric antigen receptor T-cells targeting claudin 18 are under investigation. In this review, we will discuss the major functions of claudins, their distribution in the normal as well as cancerous tissues, and their effect in cancer metastasis, with a special focus on the therapeutic targeting of claudins to improve cancer outcomes.

Peritoneal Mesothelioma-An Update

A remarkable amount of new information has been generated on peritoneal mesothelioma (PeM), ranging from nomenclature changes, including the removal of "malignant" when referring to this neoplasm and the use of the term "tumor" rather than "mesothelioma" to designate the neoplasm formerly known as "well-differentiated papillary mesothelioma", to the acknowledgment that PeMs can be associated with tumor predisposition syndromes or germline mutations. Although the disease is still more frequently seen in caucasian males, PeM is not uncommon in women. In addition, it can represent a diagnostic challenge when it has an uncommon presentation (ie, paraneoplastic syndrome or incidental finding) or when it has confounding histologic features. Ancillary testing, including immunohistochemical stains, in situ hybridization for CDKN2A or NF2 , and molecular studies, in selected cases, allows its correct diagnosis. The molecular landscape of PeM is still a work in progress; however, some findings, such as ALK gene rearrangements and EWSR1/FUS-ATF1 fusions, are specifically seen in PeM of young patients. The biological behavior of PeM is variable; however, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have markedly improved the survival of patients affected by this disease.

Hypothesis: HEG1 and claudin-4 staining will allow a diagnosis of epithelioid and biphasic mesothelioma versus non-small-cell lung carcinoma with only two stains in most cases

Separation of mesothelioma from metastatic carcinoma requires immunohistochemical support, with small batteries of stains recommended as a starting-point, but these numbers commonly expand to 10, 12 or more stains, a process that is not only expensive but frequently generates anomalous or confounding results, leading to even more stains. Here we review data on HEG1 clone SKM9-2, a new (now commercially available) mesothelioma marker and claudin-4, a broad-spectrum carcinoma marker, to ask whether these two stains are sufficient, by themselves, to separate mesotheliomas from non-small-cell lung (NSCLC) as well as other carcinomas. Data for HEG1, derived from four laboratories, showed membrane staining in 393 of 434 (91%) epithelioid/biphasic mesotheliomas and one of 360 (0.3%) NSCLC (sensitivity 91%, specificity 99.7%). Reports from seven laboratories evaluating claudin-4 in NSCLC showed positivity in 469 of 502 (93%) carcinomas and weak positivity in five of 463 (1.0%) epithelioid/biphasic mesotheliomas (sensitivity 93%, specificity 98.9%). Comparable results were found with carcinomas from other sites, except for serous and thyroid carcinomas, some of which react with HEG1 but are also positive for claudin-4. For sarcomatoid mesotheliomas, HEG1 sensitivity is modest and staining sometimes difficult to interpret. We hypothesise that the combination of HEG1 and claudin-4 immunostaining will potentially allow the separation of epithelioid/biphasic mesotheliomas from NSCLC carcinomas with high accuracy using only two immunostains in most cases. This combination will probably also work for carcinomas from most other sites, but more reports on HEG1 SKM9-2 staining of carcinomas other than NSCLC are needed. This approach would greatly simplify the diagnosis of mesothelioma.

Methylthioadenosine Phosphorylase and Breast Cancer 1 Protein-Associated Protein 1 as Biomarkers for the Peritoneal Mesothelioma

OBJECTIVES

Combination of Breast Cancer 1 protein-associated protein 1 (BAP1) and methylthioadenosine phosphorylase (MTAP) in the peritoneal mesothelioma (PeM) has yet to be explored. We aim to assess the diagnostic value of combined BAP1 and MTAP to distinguish biphasic mesothelioma (BM) from epithelioid mesothelioma (EM) with reactive stroma in peritoneum, as well as its prognostic value in PeM.

METHODS

This is a retrospective study from June 2014 to December 2021. This study included 18 cases of BM and 27 cases of EM with reactive stroma, excluded sarcomatoid, and EM without reactive stroma cases, and clinicopathological information was collected. The associations between MTAP and BAP1 levels and clinicopathological features or prognosis were analyzed. Clinical follow-up data were reviewed to correlate with pathological prognostic factors using Kaplan-Meier estimator and univariate/multivariate Cox proportional hazards regression models.

RESULTS

Loss/decrease of BAP1/MTAP was observed in 6 (33.3%) BM cases and 12 (44.4%) EM cases. In 5 (27.8%) cases, loss of or decreased BAP1/MTAP expression was observed in both EC and SC of BM. BAP1/MTAP loss/decrease was observed in 12 (44.4%) cases of only EC of EM but not in reactive stroma. Compared with histology alone, a combination of BAP1 and MTAP immunohistochemistry (IHC) in spindled PeM provides a more objective mean to distinguish BM from EM with reactive stroma. Loss/decrease of BAP1/MTAP was associated with peritoneal cancer index (PCI) score (P = 0.047) and completeness of cytoreduction (CC) score (P = 0.038). BM patients have worse overall survival (OS) than EM with reactive stroma (P = 0 .007).

CONCLUSIONS

Combination of BAP1/MTAP by IHC is helpful for differential diagnosis of peritoneal BM from EM with reactive stroma. Nevertheless, BAP1/MTAP may help to evaluate the biological behavior of PeM.