PLK-3-mediated phosphorylation of BAP1 prevents diabetic retinopathy.

Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus, and its main clinical manifestation is retinal vascular dysfunction. DR causes blindness and is a problem with significant global health implications. However, treating DR is still challenging. In this study, we aimed to explore the role of polo-like kinase-3 (PLK-3) and the potential regulatory mechanism in DR. Sprague-Dawley rats were injected intraperitoneally with streptozotocin (STZ, 60 mg/kg) to induce a rat model of DR, and rat retinal microvascular endothelial cells (RRMECs) were treated with high glucose (HG, 25 mmol/L glucose) to develop a cell model of DR. We found that PLK-3 was significantly downregulated in the retinal tissues of STZ-induced diabetic rats and HG-induced RRMECs. Lentivirus-mediated PLK-3 overexpression alleviated the histological damages in DR rats. After HG stimulation, cell proliferation, migration, and angiogenesis in RRMECs were inhibited after PLK-3 upregulation. By using label-free proteomics, we identified 82 differentially expressed proteins downstream of PLK-3, including BRCA1-associated protein 1 (BAP1), which was significantly upregulated in PLK-3-overexpressed RRMECs compared to control cells under the HG condition. In vivo and in vitro assays indicated that the forced expression of PLK-3 increased the phosphorylation of BAP1 at serine 592 and caspase-8 expression. Detailed evidence showed that BAP1-shRNA-mediated knockdown restored the cell function in HG-treated RRMECs when PLK-3 was overexpressed. Collectively, this study shows that PLK-3 alleviates retinal vascular dysfunction in DR by inhibiting the phosphorylation of BAP1. Thus, PLK-3 may develop as a promising target for the therapy of DR.

An atypical presentation of renal mass associated with BAP-1 tumor predisposition syndrome: Case report and review of literature.

BCRA-associated protein-1 (BAP-1) mutation has been associated with the development of a familiar syndrome that predisposes to tumors with a higher incidence than in general population, including melanoma and renal carcinoma. We report a 47-year-old woman diagnosed with a BAPoma (melanocytic tumor characterized by the loss of BAP-1). Due to her extensive family history with multiple neoplasms, a FDG PET-CT was performed. Consequently, she was diagnosed with an atypical renal mass, which is rarely linked to this syndrome. We review and discuss the available literature on the screening, diagnosis and treatment of renal tumors associated with BAP-1 tumor predisposition syndrome.

Clinical and genetic characteristics of BAP1-mutated non-uveal and uveal melanoma.

Background: Screening for gene mutations has become routine clinical practice across numerous tumor entities, including melanoma. BAP1 gene mutations have been identified in various tumor types and acknowledged as a critical event in metastatic uveal melanoma, but their role in non-uveal melanoma remains inadequately characterized. Methods: A retrospective analysis of all melanomas sequenced in our department from 2014-2022 (n=2650) was conducted to identify BAP1 mutated samples. Assessment of clinical and genetic characteristics was performed as well as correlations with treatment outcome. Results: BAP1 mutations were identified in 129 cases and distributed across the entire gene without any apparent hot spots. Inactivating BAP1 mutations were more prevalent in uveal (55%) compared to non-uveal (17%) melanomas. Non-uveal BAP1 mutated melanomas frequently exhibited UV-signature mutations and had a significantly higher mutation load than uveal melanomas. GNAQ and GNA11 mutations were common in uveal melanomas, while MAP-Kinase mutations were frequent in non-uveal melanomas with NF1, BRAF V600 and NRAS Q61 mutations occurring in decreasing frequency, consistent with a strong UV association. Survival outcomes did not differ among non-uveal melanoma patients based on whether they received targeted or immune checkpoint therapy, or if their tumors harbored inactivating BAP1 mutations. Conclusion: In contrast to uveal melanomas, where BAP1 mutations serve as a significant prognostic indicator of an unfavorable outcome, BAP1 mutations in non-uveal melanomas are primarily considered passenger mutations and do not appear to be relevant from a prognostic or therapeutic perspective.

MiR-31-5p alleviates septic cardiomyopathy by targeting BAP1 to inhibit SLC7A11 deubiquitination and ferroptosis.

Septic cardiomyopathy is one of the most severe and common complications in patients with sepsis and poses a great threat to their prognosis. However, the potential mechanisms and effective therapeutic drugs need to be explored. The control of cardiac cell death by miRNAs has emerged as a prominent area of scientific interest in the diagnosis and treatment of heart disorders in recent times. In the present investigation, we discovered that overexpression of miR-31-5p prevented LPS-induced damage to H9C2 cells and that miR-31-5p could inhibit BAP1 production by binding to its 3'-UTR. BRCA1-Associated Protein 1 (BAP1) is a ubiquitin carboxy-terminal hydrolase. BAP1 upregulation blocked effect of miR-31-5p on H9C2 cell injury. Moreover, BAP1 inhibited the expression of solute carrier family 7 member 11 (SLC7A11) by deubiquitinating histone 2 A (H2Aub) on the promoter of SLC7A11. Furthermore, overexpression of miR-31-5p and downregulation of BAP1 inhibited SLC7A11 mediated ferroptosis. In addition, the downregulation of SLC7A11 reversed the inhibitory effect of miR-31-5p on the expression of myocardial injury and inflammatory factors, and cell apoptosis was reversed. In conclusion, these results indicate that miR-31-5p alleviates malignant development of LPS-induced H9C2 cell injury by targeting BAP1 and regulating SLC7A11 deubiquitination-mediated ferroptosis, which confirmed the protective effect of miR-31-5p on H9C2 cell injury and revealed potential mechanisms that may provide new targets for treatment of septic cardiomyopathy.

BAP1 Deficiency Inflames the Tumor Immune Microenvironment and Is a Candidate Biomarker for Immunotherapy Response in Malignant Pleural Mesothelioma.

Introduction: Malignant pleural mesothelioma (MPM) is a rare and universally lethal malignancy with limited treatment options. Immunotherapy with immune checkpoint inhibitors (ICIs) has recently been approved for unresectable MPM, but response to ICIs is heterogeneous, and reliable biomarkers for prospective selection of appropriate subpopulations likely to benefit from ICIs remain elusive. Methods: We performed multiscale integrative analyses of published primary tumor data set from The Cancer Genome Atlas (TCGA) and the French cohort E-MTAB-1719 to unravel the tumor immune microenvironment of MPM deficient in BAP1, one of the most frequently mutated tumor suppressor genes (TSGs) in the disease. The molecular profiling results were validated in independent cohorts of patients with MPM using immunohistochemistry and multiplex immunohistochemistry. Results: We revealed that BAP1 deficiency enriches immune-associated pathways in MPM, leading to increased mRNA signatures of interferon alfa/gamma response, activating dendritic cells, immune checkpoint receptors, and T-cell inflammation. This finding was confirmed in independent patient cohorts, where MPM tumors with low BAP1 levels are associated with an inflammatory tumor immune microenvironment characterized by increased exhausted precursor T-cells and macrophages but decreased myeloid-derived suppressor cells (MDSCs). In addition, BAP1low MPM cells are in close proximity to T cells and therefore can potentially be targeted with ICIs. Finally, we revealed that BAP1-proficient MPM is associated with a hyperactive mitogen-activated protein kinase (MAPK) pathway and may benefit from treatment with MEK inhibitors (MEKis). Conclusion: Our results suggest that BAP1 plays an immunomodulatory role in MPM and that BAP1-deficient MPM may benefit from immunotherapy, which merits further clinical investigation.

Clinical and Genomic Features of Patients with Renal Cell Carcinoma and Advanced Chronic Kidney Disease: Analysis of a Multi-Institutional Database.

BACKGROUND: Patients with advanced chronic kidney disease (ACKD) are at an increased risk of developing renal cell carcinoma (RCC), but molecular alterations in RCC specimens arising from ACKD and overall survival (OS) in affected patients are not well defined. PATIENTS AND METHODS: Using the Oncology Research Information Exchange Network (ORIEN) Total Cancer Care® protocol, 296 consented adult patients with RCC and somatic tumor whole exome sequencing were included. Patients with ACKD were defined as those with serum creatinine ≥1.5 mg/dL prior to RCC diagnosis. RESULTS: Of 296 patients with RCC, 61 met the criteria for ACKD. The most common somatic mutations in the overall cohort were in VHL (126, 42.6%), PBRM1 (102, 34.5%), and SETD2 (54, 18.2%). BAP1 had a decreased mutational frequency in RCC specimens from patients without ACKD as compared to those with ACKD (10.6% versus 1.6%), but this was not statistically significant in univariable (OR 0.14, p = 0.056) or multivariable (OR 0.15, p = 0.067) analysis. Median OS was not reached in either cohort. CONCLUSIONS: Using the clinicogenomic ORIEN database, our study found lower rates of BAP1 mutations in RCC specimens from patients with ACKD, which may reflect a BAP1-independent mutational driver of RCC in patients with ACKD.

Paired Primary and Recurrent Rhabdoid Meningiomas: Cytogenetic Alterations, BAP1 Gene Expression Profile and Patient Outcome.

Rhabdoid meningiomas (RM) are a rare meningioma subtype with a heterogeneous clinical course which is more frequently associated with recurrence, even among tumors undergoing-complete surgical removal. Here, we retrospectively analyzed the clinical-histopathological and cytogenetic features of 29 tumors, from patients with recurrent (seven primary and 14 recurrent tumors) vs. non-recurrent RM (n = 8). Recurrent RM showed one (29%), two (29%) or three (42%) recurrences. BAP1 loss of expression was found in one third of all RM at diagnosis and increased to 100% in subsequent tumor recurrences. Despite both recurrent and non-recurrent RM shared chromosome 22 losses, non-recurrent tumors more frequently displayed extensive losses of chromosome 19p (62%) and/or 19q (50%), together with gains of chromosomes 20 and 21 (38%, respectively), whereas recurrent RM (at diagnosis) displayed more complex genotypic profiles with extensive losses of chromosomes 1p, 14q, 18p, 18q (67% each) and 21p (50%), together with focal gains at chromosome 17q22 (67%). Compared to paired primary tumors, recurrent RM samples revealed additional losses at chromosomes 16q and 19p (50% each), together with gains at chromosomes 1q and 17q in most recurrent tumors (67%, each). All deceased recurrent RM patients corresponded to women with chromosome 17q gains, although no statistical significant differences were found vs. the other RM patients.

Targeting inflammatory factors for chemoprevention and cancer interception to tackle malignant mesothelioma.

Mesothelioma is an incurable cancer of the mesothelial lining often caused by exposure to asbestos. Asbestos-induced inflammation is a significant contributing factor in the development of mesothelioma, and genetic factors also play a role in the susceptibility to this rapidly progressive and treatment-resistant malignancy. Consequently, novel approaches are urgently needed to treat mesothelioma and prevent or reduce the overall incidence of this fatal disease. In this research perspective, we review the current state of chemoprevention and cancer interception progress in asbestos-induced mesothelioma. We discuss the different preclinical mouse models used for these investigations and the inflammatory factors that may be potential targets for mesothelioma prevention. Preliminary studies with naturally occurring phytochemicals and synthetic agents are reviewed. Results of previous clinical chemoprevention trials in populations exposed to asbestos and considerations regarding future trials are also presented.

The significance of BAP1 and MTAP/CDKN2A expression in well-differentiated papillary mesothelial tumour: a series of 21 cases and a review of the literature.

The nomenclature and diagnostic criteria of well-differentiated papillary mesothelial tumour (WDPMT) have been changed in the 2021 World Health Organization (WHO) classification of thoracic tumours, and a new entity, mesothelioma in situ (MIS), introduced. Histologically these two entities may be similar. However, MIS is regarded as a precursor to invasive mesothelioma and requires demonstration of loss of BAP1 and/or MTAP/CDKN2A for diagnosis, whereas performance of these ancillary tests is desirable but not essential for a diagnosis of WDPMT, in which the significance of BAP1 and/or MTAP/CDKN2A loss is not well understood or well defined. Against this backdrop, we undertook an investigation of 21 cases of WDPMT, identified from our case files and diagnosed according to 2021 WHO criteria, to explore the relationship between histology and BAP1 and MTAP/CDKN2A expression with clinical features including asbestos exposure, focality of tumours and clinical outcome. There were 18 women and three men, with ages ranging from 23-77 years (median 62 years), in which six had a history of asbestos exposure, two had no exposure, and in 13 exposure history was unavailable. Of 20 peritoneal tumours and one pleural tumour, 13 were detected incidentally at the time of surgery for unrelated conditions and eight peritoneal tumours were multifocal at the time of diagnosis. BAP1 immunohistochemistry (IHC) was performed in all 21 tumours, with nine tumours showing BAP1 expression loss. MTAP/CDKN2A testing was performed in 14 tumours, comprising MTAP IHC in 12 and CDKN2A fluorescence in situ hybridisation (FISH) in two, with three tumours showing MTAP/CDKN2A expression loss. Two tumours with MTAP/CDKN2A loss also showed BAP1 expression loss. Four patients progressed to invasive mesothelioma, including one male with a pleural tumour and asbestos exposure, and three females with multifocal peritoneal tumours, two with asbestos exposure and one without exposure. BAP1 expression loss was seen in all tumours from the four patients who progressed to invasive mesothelioma, whilst two of these tumours showed retained MTAP IHC and two were not tested. There was one patient with a tumour with MTAP loss and retained BAP1 who died from unrelated causes 5 months after diagnosis. Eight patients received WDPMT-specific treatment in addition to the initial excision. Survival for all patients ranged from 4-218 months, with one patient dying of mesothelioma at 49 months. Based on our results in this series of 21 patients with WDPMT diagnosed according to 2021 WHO criteria, we propose that WDPMT with BAP1 expression loss may best be regarded as papillary MIS and that a history of asbestos exposure and the presence of multifocal tumours in patients diagnosed with WDPMT should prompt ancillary testing with BAP1 IHC. Further we propose that BAP1 IHC should be essential in the diagnosis of WDPMT, with the diagnosis restricted to those tumours which show retained BAP1 expression. However more studies in larger cohorts of patients are needed to explore the relationship between BAP1 expression and MTAP loss in WDPMT, which will help to define this entity and separate it more clearly from MIS and invasive mesothelioma.

Regulation of Med1 protein by overexpression of BAP1 in breast cancer cells.

Med1 binds to a nuclear receptor and regulates transcription. Elevated Med1 protein expression promotes cancer growth in hormone-dependent breast and prostate cancers. Med1 protein expression was investigated by deubiquitinating enzymes (DUBs) overexpression in breast cancer cell lines. Various DNA constructs of SRT-DUBs were overexpressed in the MCF7 cell line, and Med1 protein expression was investigated by western blotting. The cell growth and in vitro invasion assay were performed in BRCA1-associated protein 1 (BAP1) wild type and mutant (C91A) overexpressed cells. Ubiquitination of the Med1 protein was observed, and Med1 protein expression and transcriptional activity were verified by various DUBs overexpressed. Although Med1 protein expression increased upon the overexpression of BAP1, it was not affected by the overexpression of BAP1 mutant (C91A). BAP1 was increased by the E2 treatment, which has an important effect on the breast cancer growth, and cell growth was decreased by BAP1 C91A overexpression. However, metastatic capacities were decreased by BAP1. In addition, the binding between the Med1 and the BAP1 protein was observed. These data suggested that BAP1 regulated Med1 protein expression in breast cancer cells and involved in cancer cell growth and metastasis by binding to Med1 protein.

Association between Parkinson's Disease and Cancer: New Findings and Possible Mediators.

Epidemiological evidence points to an inverse association between Parkinson's disease (PD) and almost all cancers except melanoma, for which this association is positive. The results of multiple studies have demonstrated that patients with PD are at reduced risk for the majority of neoplasms. Several potential biological explanations exist for the inverse relationship between cancer and PD. Recent results identified several PD-associated proteins and factors mediating cancer development and cancer-associated factors affecting PD. Accumulating data point to the role of genetic traits, members of the synuclein family, neurotrophic factors, the ubiquitin-proteasome system, circulating melatonin, and transcription factors as mediators. Here, we present recent data about shared pathogenetic factors and mediators that might be involved in the association between these two diseases. We discuss how these factors, individually or in combination, may be involved in pathology, serve as links between PD and cancer, and affect the prevalence of these disorders. Identification of these factors and investigation of their mechanisms of action would lead to the discovery of new targets for the treatment of both diseases.

Circ_0087851 suppresses colorectal cancer malignant progression through triggering miR-593-3p/BAP1-mediated ferroptosis.

BACKGROUND: Emerging research has validated that circular RNAs (circRNAs) have indispensable regulatory functions in tumorigenesis, including colorectal cancer (CRC). Ferroptosis is a specific cell death form and implicates in the malignant progression of tumors. Here, this study aimed to investigate the biofunction of circ_0087851 in tumor progression and ferroptosis of CRC, as well as its underlying molecular mechanism. METHODS: The expression pattern of circ_0087851 in CRC was validated by qRT-PCR. The biological characteristics of circ_0087851 in CRC were assessed through CCK-8, colony formation and transwell assays in vitro. The ferroptosis was measured using ferroptosis-related reagents on iron, Fe2+, and lipid ROS detection. Bioinformatics, luciferase reporter, and RNA pulldown assays were employed to reveal the circ_0087851-mediated regulatory network. In addition, the effect of circ_0087851 on tumor growth in vivo was detected using a xenograft model. RESULTS: Circ_0087851 was notably diminished in CRC tissues and cells. Functionally, overexpression of circ_0087851 suppressed CRC cell growth, migration, invasion, and facilitated ferroptosis in vitro. Meanwhile, circ_0087851 upregulation impeded CRC growth in vivo. Mechanistically, circ_0087851 functioned as a molecular sponge for miR-593-3p, and BRCA1 associated protein 1 (BAP1) was identified as a downstream target of miR-593-3p. Besides, rescue experiments revealed that miR-593-3p overexpression or silencing of BAP1 reversed circ_0087851-mediated CRC progression. CONCLUSION: Circ_0087851 performed as a tumor suppressor and ferroptosis promoter by the miR-593-3p/BAP1 axis, providing novel biomarker and therapeutic target for the clinical management of CRC.

BAP1 Loss, Nuclear Grading, and Nonepithelioid Features in the Diagnosis of Mesothelioma in Italy: Nevermore without the Pathology Report.

The pathologic diagnosis of pleural mesothelioma is generally based on international guidelines, but no compulsory points based on different drugs approvals in different European countries are required to be reported. According to the last (2021) edition of the World Health Organization classification of pleural tumors, the nuclear grade of epithelioid-type mesothelioma should be always inserted in the pathologic report, while the presence of BRCA-associated protein-1 (BAP1) (clone C4) loss and a statement on the presence of the sarcomatoid/nonepithelioid component are fundamental for both a screening of patients with suspected BAP1 tumor predisposition syndrome and the eligibility to perform first-line immunotherapy at least in some countries. Several Italian experts on pleural mesothelioma who are deeply involved in national scientific societies or dedicated working groups supported by patient associations agreed that the pathology report of mesothelioma of the pleura should always include the nuclear grade in the epithelioid histology, which is an overt statement on the presence of sarcomatoid components (at least 1%, in agreement with the last classification of pleural mesothelioma) and the presence of BAP1 loss (BAP1-deficient mesothelioma) or not (BAP1-retained mesothelioma) in order to screen patients possibly harboring BAP1 tumor predisposition syndrome. This review aims to summarize the most recent data on these three important elements to provide evidence regarding the possible precision needs for mesothelioma.

Emerging New Targets in Systemic Therapy for Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a heterogeneous cancer composed of distinct molecular and pathologic subtypes. Unfortunately, MPM is aggressive, and current therapies for advanced, unresectable disease remain limited to cytotoxic chemotherapy and immunotherapy. Our understanding of the genomic landscape of MPM is steadily growing, while the discovery of effective targeted therapies in MPM has advanced more slowly than in other solid tumors. Given the prevalence of alterations in tumor suppressor genes in MPM, it has been challenging to identify actionable targets. However, efforts to characterize the genetic signatures in MPM over the last decade have led to a range of novel targeted therapeutics entering early-phase clinical trials. In this review, we discuss the advancements made thus far in targeted systemic therapies in MPM and the future direction of targeted strategies in patients with advanced MPM.

Mesothelioma: morphologic and immunohistochemical findings.

This paper reviews some basic and some new concepts in the diagnosis of mesothelioma. The term "malignant mesothelioma" is no longer recommended; rather, any tumor labeled "mesothelioma" is presumed to be malignant. Clinical and radiologic information is very useful in the diagnosis of mesothelioma; in particular, nodular pleural thickening on CT is usually a marker of malignancy. The literature on markers that separate mesotheliomas from metastatic carcinomas has become very complex and frequently misleading, with many recommended markers actually demonstrating poor specificity. However, newer data show that a combination of HEG1 (clone SKM9-2) and claudin­4 staining provides extremely high accuracy in separating epithelioid mesotheliomas from non-small-cell lung carcinomas with just two immunostains. This combination works at other sites as well, but caution should be used when high-grade serous carcinoma is in the differential, because all "mesothelioma" markers can also stain high-grade serous carcinomas. There are, unfortunately, no sensitive or specific markers for sarcomatoid mesotheliomas. A variety of immunohistochemical and fluorescence in situ hybridization (FISH) markers are useful in separating benign from malignant mesothelial proliferations; immunohistochemal staining for BAP1, MTAP (or CDKN2A FISH), and NF2/Merlin (or NF2 FISH) will enable the diagnosis of most mesotheliomas. Mesothelioma in situ is now recognized as either a single layer of bland cuboidal mesothelial cells that have lost BAP1, and sometimes MTAP, on immunohistochemical staining, or a process that is morphologically identical to a well-differentiated papillary mesothelial tumor that has lost BAP1/MTAP. Mesothelioma in situ probably always progresses to invasive mesothelioma, but this process is often quite slow.

Expression of fibroblast growth factor receptor 2 (FGFR2) in combined hepatocellular-cholangiocarcinoma and intrahepatic cholangiocarcinoma: clinicopathological study.

Genetic alterations including fusions in fibroblast growth factor receptor 2 (FGFR2) are detected in 10-20% of intrahepatic cholangiocarcinoma (iCCA), and FGFR2 inhibitors are effective for the treatment of iCCA. We examined a prevalence of FGFR2 genetic alterations and their clinicopathological significance in combined hepatocellular-cholangiocarcinoma (cHCC-CCA). FGFR2 expression, which is a surrogate marker for FGFR2 genetic alterations, was immunohistochemically assessed in the liver sections from 75 patients with cHCC-CCA, 35 with small duct-type iCCA, 30 with large duct-type iCCA, and 35 with hepatocellular carcinoma (HCC). FGFR2 genetic alterations were detected by reverse transcription-PCR and direct sequence. An association of FGFR2 expression with clinicopathological features was investigated in cHCC-CCAs. FGFR2 expression was detected in significantly more patients with cHCC-CCA (21.3%) and small duct-type iCCA (25.7%), compared to those with large duct-type iCCA (3.3%) and HCC (0%) (p < 0.05). FGFR2-positive cHCC-CCAs were significantly smaller size (p < 0.05), with more predominant cholangiolocarcinoma component (p < 0.01) and less nestin expression (p < 0.05). Genetic alterations of ARID1A and BAP1 and multiple genes were significantly more frequent in FGFR2-positive cHCC-CCAs (p < 0.05). 5'/3' imbalance in FGFR2 genes indicating exon18-truncated FGFR2 was significantly more frequently detected in FGFR2-positive cHCC-CCAs and small duct iCCAs, compared to FGFR2-negative ones (p < 0.05). FGFR2::BICC fusion was detected in a case of cHCC-CCAs. FGFR2 genetic alterations may be prevalent in cHCC-CCAs as well as small duct-type iCCAs, which suggest cHCC-CCAs may also be a possible therapeutic target of FGFR2 inhibitors.

BRCA1-associated protein 1: Tumor predisposition syndrome and Kury-Isidor syndrome, from genotype-phenotype correlation to clinical management.

The BAP1 tumor suppressor gene encodes a deubiquitinase enzyme involved in several cellular activities, including DNA repair and apoptosis. Germline pathogenic variants in BAP1 have been associated with heritable conditions including BAP1 tumor predisposition syndrome 1 (BAP1-TPDS1) and a neurodevelopmental disorder known as Kury-Isidor syndrome (KURIS). Both these conditions are caused by monoallelic, dominant alterations of BAP1 but have never been reported in the same subject or family, suggesting a mutually exclusive genotype-phenotype correlation. This distinction is extremely important considering the early onset and aggressive nature of the types of cancer reported in individuals with TPDS1. Genetic counseling in subjects with germline BAP1 variants is fundamental to predicting the effect of the variant and the expected phenotype, assessing the potential risk of developing cancer for the tested subject and the family members who may carry the same variant and providing the multidisciplinary clinical team with the proper information to establish precise surveillance and management protocols.

Reliably making the primary diagnosis of mesothelioma utilizing serous fluid cytology specimens: an institutional experience.

INTRODUCTION: The diagnosis of mesothelioma has historically been challenging, especially on serous fluid cytology (SFC). Distinguishing between reactive and neoplastic mesothelial cells can be difficult on cytomorphology alone. However, additional ancillary tests, such as BRCA1 associated protein-1 immunohistochemistry and fluorescence in situ hybridization for cyclin-dependent kinase inhibitor 2A deletion, can provide a sensitive and highly specific method of proving malignancy. MATERIALS AND METHODS: SFC specimens diagnosed as mesothelioma, suspicious for mesothelioma (SM), and atypical mesothelial cells (AMCs) since 2012 were identified by querying the laboratory information system. Clinical data and pathologic parameters were gathered. RESULTS: One hundred ten cases of mesothelioma, SM, and AMC were identified. Of these, 61 cases had a definitive diagnosis of mesothelioma on SFC. Average age at SFC diagnosis was 67 years (26-87 years), with most patients being male (67%). Out of the 61 cases, 11 cases (18%) had an initial diagnosis of mesothelioma made on SFC specimens, with 5 of these 11 cases being in patients that never received a histologic diagnosis of mesothelioma. Ancillary studies were utilized in all 11 cases. An initial diagnosis of metastatic mesothelioma was made on SFC in 9 cases (15%). For 6 of these 9 cases, the SFC diagnosis was the sole diagnosis of metastatic mesothelioma without a companion histologic diagnosis. In addition, 15 cases were diagnosed as SM, with 11 of these cases following a definitive mesothelioma diagnosis. Thirty-four cases were diagnosed as AMC, with 27 cases following a definitive mesothelioma diagnosis. CONCLUSIONS: The diagnosis of mesothelioma can be reliably made on SFC with the appropriate cytomorphology criteria and/or confirmatory ancillary testing.

Pleural mesothelioma (PMe): The evolving molecular knowledge of a rare and aggressive cancer.

Mesothelioma is a type of late-onset cancer that develops in cells covering the outer surface of organs. Although it can affect the peritoneum, heart, or testicles, it mainly targets the lining of the lungs, making pleural mesothelioma (PMe) the most common and widely studied mesothelioma type. PMe is caused by exposure to fibres of asbestos, which when inhaled leads to inflammation and scarring of the pleura. Despite the ban on asbestos by most Western countries, the incidence of PMe is on the rise, also facilitated by a lack of specific symptomatology and diagnostic methods. Therapeutic options are also limited to mainly palliative care, making this disease untreatable. Here we present an overview of biological aspects underlying PMe by listing genetic and molecular mechanisms behind its onset, aggressive nature, and fast-paced progression. To this end, we report on the role of deubiquitinase BRCA1-associated protein-1 (BAP1), a tumour suppressor gene with a widely acknowledged role in the corrupted signalling and metabolism of PMe. This review aims to enhance our understanding of this devastating malignancy and propel efforts for its investigation.

Quantification of eosinophilic area and its potential molecular feature in clear cell renal cell carcinoma.

OBJECTIVE: Previous studies have acknowledged the presence of eosinophilic cytoplasm in clear cell renal cell carcinoma, yet the precise quantification method and potential molecular attributes in clear cell renal cell carcinoma remain elusive. This study endeavours to precisely quantify the eosinophilic attribute and probe into the molecular mechanisms governing its presence in clear cell renal cell carcinoma. METHODS: Data from cohorts of clear cell renal cell carcinoma patients who underwent nephrectomy, comprising The Cancer Genome Atlas cohort (n = 475) and Sun Yat-sen University Cancer Center cohort (n = 480), were aggregated to assess the eosinophilic attribute. Additionally, Omics data from Clinical Proteomic Tumor Analysis Consortium (CPTAC) (n = 58) were leveraged to explore the potential molecular features associated with eosinophilic clear cell renal cell carcinoma. Employing receiver operating characteristic curve analysis, the proportion of tumour cells with eosinophilic cytoplasm was determined, leading to the classification of each cohort into distinct groups: a clear group (<5%) and an eosinophilic group (≥5%). RESULTS: In both cohorts, the eosinophilic feature consistently correlated with higher International Society of Urological Pathology (ISUP) grade, elevated tumor stage, and the presence of necrosis. Furthermore, the Kaplan-Meier method demonstrated that patients in the eosinophilic group exhibited shorter overall survival or disease-free survival compared with those in the clear group, a pattern reaffirmed in various stratified survival analyses. Intriguingly, within The Cancer Genome Atlas cohort, the pathological characterization of cell cytoplasm (eosinophilic vs. clear) emerged as an independent risk factor for overall survival (hazard ratio = 2.507 [95% confidence interval: 1.328-4.733], P = 0.005) or disease-free survival (hazard ratio = 1.730 [95% confidence interval: 1.062-2.818], P = 0.028) via Cox regression analysis. Moreover, multi-Omics data unveiled frequent BAP1 mutations and down-regulation of Erythroblast Transformation-Specific-Related Gene associated with the eosinophilic feature in clear cell renal cell carcinoma. Additionally, patients with low expression of Erythroblast Transformation-Specific-Related Gene showed worse overall survival (P < 0.001). CONCLUSIONS: The quantification of the eosinophilic feature serves as a robust predictor of clinical prognosis in clear cell renal cell carcinoma. Furthermore, the manifestation of this feature may be linked to BAP1 mutations and the down-regulation of Erythroblast Transformation-Specific-Related Gene in clear cell renal cell carcinoma. Significantly, the expression levels of Erythroblast Transformation-Specific-Related Gene manifest as an exemplary prognostic marker, providing exceptional predictive accuracy for the clinical prognosis in clear cell renal cell carcinoma.