[Research progress on pathogenesis of malignant mesothelioma].

The occurrence of malignant mesothelioma is related to exposure of asbestos. And many researchers have conducted in-depth analysis of the molecular changes of mesothelioma, showed that its molecular characteristics were chromosome changes, including chromosome rearrangement, gene mutation and gene deletion. Recent studies have strengthened our understanding of molecular characterization of mesothelioma, such as targeted mutations of tumor suppressor genes, differential gene expression, changes of miRNA and signal pathways. It is of great significance for the early diagnosis, clinical treatment and prognosis of malignant mesothelioma to explore the pathogenesis and development of malignant mesothelioma. This article reviews the research progress on the pathogenesis and carcinogenesis-related molecules of malignant mesothelioma.

Effects of tumor-infiltrating CD8+ T cells, PD1/PD-L1 axis, and expression patterns of HLA class I on the prognosis of patients with malignant pleural mesothelioma who underwent extra-pleural pneumonectomy.

Programmed cell death protein-1 (PD1), PD1 ligand 1 (PD-L1), and human leukocyte antigen (HLA) class I molecule play pivotal roles in T cell-induced anti-tumor immunity; however, the clinical impact of these parameters in resected malignant pleural mesothelioma (MPM) cases is unknown. We immunohistochemically evaluated the tumor infiltrated lymphocytes (TILs), PD1/PD-L1 axis, and expression of HLA class I in resected specimens from 58 patients with MPM who underwent extra-pleural pneumonectomy (EPP). Higher infiltration of CD3-TIL, CD8-TIL, and PD1-TIL, loss of HLA class I, and overexpression of PD-L1 by tumor cells (PD-L1 TC) or immune cells (PD-L1 IC) were observed in 34 (58.6%), 27 (46.6%), 41 (70.7%), 45 (77.6%), 29 (50.0%), and 33 (56.4%) of 58 cases, respectively. Interestingly, the CD3-TIL score positively correlated with PD-L1 TC and PD1-TIL scores. HLA class I expression level was inversely correlated with the expression levels of PD-L1 TC and PD-L1 IC. Multivariate analysis showed that age, histology, and node metastasis were independent prognostic factors for 5-year overall survival (OS) and loss of HLA class I coincided with a positive prognosis (p = 0.011). The concomitant lack of infiltrating CD8+ T cells with no loss of HLA class I predicted worse 5-year OS (p = 0.007). Moreover, cluster classifications among multiple immunoparameters showed that categories among CD3/PD-L1 TC/HLA class I (p = 0.043), CD8/PD1/HLA class I (p = 0.032), CD8/PD-L1 TC/HLA class I (p = 0.011), and PD1/PD-L1 TC/HLA class I (p = 0.032) predicted 5-year OS in EPP cases for MPM. These immunoparameters could guide surgical indications for patients with MPM.

[Research progress on immunohistochemical diagnostic markers for malignant pleural mesothelioma].

Malignant pleural mesothelioma (MPM) is a malignant tumor originating from the pleura, characterized by insidious onset, strong local invasiveness, short survival period, and poor prognosis. Clinical diagnosis is of paramount importance for the treatment and prognosis of MPM. Currently, the gold standard for diagnosing MPM is the results of histopathological examinations. Immunohistochemistry (IHC) is an effective auxiliary method in pathological diagnosis. Preliminary examinations can use two positive markers and two negative markers to distinguish pleural metastatic tumors, with additional antibodies selected based on differential diagnosis. The combined use of IHC markers plays a crucial role in the differential diagnosis between MPM and other tumors. This article primarily introduces commonly used IHC markers in MPM and the research progress of novel IHC markers in screening and differential diagnosis, aiming to provide reference for the clinical diagnosis and treatment of MPM.

[Prognostic significance and immune cell infiltration analysis of differentially expressed genes in malignant pleural mesothelioma].

Objective: To explore and analyze differential expressed genes in malignant pleural mesothelioma (MPM) by bioinformatics method, and to study their prognostic value in MPM and their potential role in immunotherapy. Methods: In January 2022, the dataset GSE51024 was downloaded from the GEO database, and MPM (55 cases) and normal tissue (41 cases) samples were obtained. Using R software and HMDD and miRNet database, MPM-related differential genes were screened and co-expressed genes were identified. Co-expressed genes were enriched and functionally annotated, and protein-protein interaction (PPI) networks were constructed and key genes were identified using the STRING database and Cytoscape software. TRRUST and GEPIA databases were used to predict transcription factors of key genes and to analyze prognosis and survival. The correlation between key genes and the degree of infiltration of immune cells was analyzed using TIMER. Results: A total of 435 co-expressed genes were obtained, which were mainly concentrated in the extracellular matrix tissue and the signaling pathways of cell adhesion molecules. Combined with PPI and TRRUST database, seven key MPM prognostic genes were identified. Among them, cyclin 20 (CDC20) , cell cycle checkpoint kinase 1 (CHEK1) , enhancer of Zeste homolog 2 (EZH2) , ribonucleotide reductase subunit M2 (RRM2) , topoisomerase 2A (TOP2A) , ubiquitin like plant homeodomain and ring finger domain 1 (UHRF1) were significantly up-regulated in MPM, while cyclin A1 (CCNA1) was significantly down-regulated. The expressions of CCNA1, CDC20, CHEK1, EZH2, RRM2, TOP2A and UHRF1 genes were significantly associated with MPM overall survival (P<0.05) . The expressions of CDC20, CHEK1, EZH2, RRM2 and TOP2A genes were positively correlated with B cells and dendritic cells (P<0.05) , and negatively correlated with neutrophils (P<0.05) . Conclusion: CCNA1, CDC20, CHEK1, EZH2, RRM2, TOP2A and UHRF1 may be potential prognostic markers in MPM patients, and their expressions may be related to MPM tumor immunity.

Emerging biological therapies for the treatment of malignant pleural mesothelioma.

Introduction: Malignant pleural mesothelioma (MPM) has limited treatment options with minimal new therapy approvals for unresectable disease in the past 15 years. However, considerable work has occurred to develop immunotherapies and biomarker driven therapy to improve patient outcomes over this period.Areas covered: This review examines current standard of care systemic therapy in the first- and second line setting. The last 12 months has seen 2 significant trials (Checkmate 743 and CONFIRM) which provide evidence supporting the role of immunotherapy in the management of MPM. Further trials are underway to assess the role of combination chemoimmunotherapy and personalized therapy. Additionally, a large number of clinical trials are ongoing to assess the efficacy of oncoviral, dendritic cell, anti-mesothelin and chimeric antigen receptor T cell therapy in the treatment of MPM.Expert opinion: Recent Phase III trial results have established a role for immunotherapy in the management of MPM. The optimal sequencing and combination of chemotherapy and immunotherapy remains to be determined. Novel therapies for MPM are promising however efficacy remains to be determined and issues remain regarding access to and delivery of these therapies.

The Role of E-Cadherin and microRNA on FAK Inhibitor Response in Malignant Pleural Mesothelioma (MPM).

Malignant pleural mesothelioma (MPM) is an aggressive malignancy with limited effective treatment options. Focal adhesion kinase (FAK) inhibitors have been shown to efficiently suppress MPM cell growth initially, with limited utility in the current clinical setting. In this study, we utilised a large collection of MPM cell lines and MPM tissue samples to study the role of E-cadherin (CDH1) and microRNA on the efficacy of FAK inhibitors in MPM. The immunohistochemistry (IHC) results showed that the majority of MPM FFPE samples exhibited either the absence of, or very low, E-cadherin protein expression in MPM tissue. We showed that MPM cells with high CDH1 mRNA levels exhibited resistance to the FAK inhibitor PND-1186. In summary, MPM cells that did not express CDH1 mRNA were sensitive to PND-1186, and MPM cells that retained CDH1 mRNA were resistant. A cell cycle analysis showed that PND-1186 induced cell cycle disruption by inducing the G2/M arrest of MPM cells. A protein-protein interaction study showed that EGFR is linked to the FAK pathway, and a target scan of the microRNAs revealed that microRNAs (miR-17, miR221, miR-222, miR137, and miR148) interact with EGFR 3'UTR. Transfection of MPM cells with these microRNAs sensitised the CHD1-expressing FAK-inhibitor-resistant MPM cells to the FAK inhibitor.

Tissue expression of lactate transporters (MCT1 and MCT4) and prognosis of malignant pleural mesothelioma (brief report).

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm of the pleura, mainly related to asbestos exposure. As in other solid tumors, malignant cells exhibit high glucose uptake and glycolytic rates with increased lactic acid efflux into the interstitial space. Lactate transport into and out of cells, crucial to maintaining intracellular pH homeostasis and glycolysis, is carried out by monocarboxylate transporters (MCTs) and the chaperone basigin (CD147). We set out to examine the clinical significance of basigin, MCT1 and MCT4 in the context of MPM and to evaluate their expression in relation to the evolution of the disease. METHODS: We used immunohistochemistry to measure the expression of basigin, MCT1 and MCT4 in a cohort of 135 individuals with MPM compared to a series of 15 non-MPM pleura specimens. Moreover, by Kaplan-Meier and Cox analyses we evaluated whether an expression over the average of these markers could be associated with the patients' overall survival (OS). RESULTS: We detected positive staining of basigin, MCT1, and MCT4 in most MPM specimens. In particular, MCT4 was always positive in malignant tissues but undetectable in the 4 normal pleural specimens incorporated within the tissue microarray. This was confirmed in the additional series of 15 normal pleural samples. Moreover, MCT4 expression was significantly associated with reduced OS. CONCLUSION: In this study, the tissue expression of basigin did not prove to be exploitable as a diagnostic or prognostic marker for MPM patients. The expression of MCT1 was not informative either, being tightly correlated with that of basigin. However, the expression of MCT4 showed promise as a diagnostic/therapeutic and prognostic biomarker.

Heterogeneous Contributing Factors in MPM Disease Development and Progression: Biological Advances and Clinical Implications.

Malignant pleural mesothelioma (MPM) tumors are remarkably aggressive and most patients only survive for 5-12 months; irrespective of stage; after primary symptoms appear. Compounding matters is that MPM remains unresponsive to conventional standards of care; including radiation and chemotherapy. Currently; instead of relying on molecular signatures and histological typing; MPM treatment options are guided by clinical stage and patient characteristics because the mechanism of carcinogenesis has not been fully elucidated; although about 80% of cases can be linked to asbestos exposure. Several molecular pathways have been implicated in the MPM tumor microenvironment; such as angiogenesis; apoptosis; cell-cycle regulation and several growth factor-related pathways predicted to be amenable to therapeutic intervention. Furthermore, the availability of genomic data has improved our understanding of the pathobiology of MPM. The MPM genomic landscape is dominated by inactivating mutations in several tumor suppressor genes; such as CDKN2A; BAP1 and NF2. Given the complex heterogeneity of the tumor microenvironment in MPM; a better understanding of the interplay between stromal; endothelial and immune cells at the molecular level is required; to chaperone the development of improved personalized therapeutics. Many recent advances at the molecular level have been reported and several exciting new treatment options are under investigation. Here; we review the challenges and the most up-to-date biological advances in MPM pertaining to the molecular pathways implicated; progress at the genomic level; immunological progression of this fatal disease; and its link with developmental cell pathways; with an emphasis on prognostic and therapeutic treatment strategies.

Heterogeneity in Immune Cell Content in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with limited therapy options and dismal prognosis. In recent years, the role of immune cells within the tumor microenvironment (TME) has become a major area of interest. In this review, we discuss the current knowledge of heterogeneity in immune cell content and checkpoint expression in MPM in relation to prognosis and prediction of treatment efficacy. Generally, immune-suppressive cells such as M2 macrophages, myeloid-derived suppressor cells and regulatory T cells are present within the TME, with extensive heterogeneity in cell numbers. Infiltration of effector cells such as cytotoxic T cells, natural killer cells and T helper cells is commonly found, also with substantial patient to patient heterogeneity. PD-L1 expression also varied greatly (16-65%). The infiltration of immune cells in tumor and associated stroma holds key prognostic and predictive implications. As such, there is a strong rationale for thoroughly mapping the TME to better target therapy in mesothelioma. Researchers should be aware of the extensive possibilities that exist for a tumor to evade the cytotoxic killing from the immune system. Therefore, no "one size fits all" treatment is likely to be found and focus should lie on the heterogeneity of the tumors and TME.

Targeting glucosylceramide synthase induction of cell surface globotriaosylceramide (Gb3) in acquired cisplatin-resistance of lung cancer and malignant pleural mesothelioma cells.

BACKGROUND: Acquired resistance to cisplatin treatment is a caveat when treating patients with non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma (MPM). Ceramide increases in response to chemotherapy, leading to proliferation arrest and apoptosis. However, a tumour stress activation of glucosylceramide synthase (GCS) follows to eliminate ceramide by formation of glycosphingolipids (GSLs) such as globotriaosylceramide (Gb3), the functional receptor of verotoxin-1. Ceramide elimination enhances cell proliferation and apoptosis blockade, thus stimulating tumor progression. GSLs transactivate multidrug resistance 1/P-glycoprotein (MDR1) and multidrug resistance-associated protein 1 (MRP1) expression which further prevents ceramide accumulation and stimulates drug efflux. We investigated the expression of Gb3, MDR1 and MRP1 in NSCLC and MPM cells with acquired cisplatin resistance, and if GCS activity or MDR1 pump inhibitors would reduce their expression and reverse cisplatin-resistance. METHODS: Cell surface expression of Gb3, MDR1 and MRP1 and intracellular expression of MDR1 and MRP1 was analyzed by flow cytometry and confocal microscopy on P31 MPM and H1299 NSCLC cells and subline cells with acquired cisplatin resistance. The effect of GCS inhibitor PPMP and MDR1 pump inhibitor cyclosporin A for 72h on expression and cisplatin cytotoxicity was tested. RESULTS: The cisplatin-resistant cells expressed increased cell surface Gb3. Cell surface Gb3 expression of resistant cells was annihilated by PPMP whereas cyclosporin A decreased Gb3 and MDR1 expression in H1299 cells. No decrease of MDR1 by PPMP was noted in using flow cytometry, whereas a decrease of MDR1 in H1299 and H1299res was indicated with confocal microscopy. No certain co-localization of Gb3 and MDR1 was noted. PPMP, but not cyclosporin A, potentiated cisplatin cytotoxicity in all cells. CONCLUSIONS: Cell surface Gb3 expression is a likely tumour biomarker for acquired cisplatin resistance of NSCLC and MPM cells. Tumour cell resistance to MDR1 inhibitors of cell surface MDR1 and Gb3 could explain the aggressiveness of NSCLC and MPM. Therapy with GCS activity inhibitors or toxin targeting of the Gb3 receptor may substantially reduce acquired cisplatin drug resistance of NSCLC and MPM cells.

Nivolumab and ipilimumab in the real-world setting in patients with mesothelioma.

OBJECTIVES: Nivolumab (anti-PD-1) plus ipilimumab (anti-CTLA-4) is a new first-line treatment combination for patients with pleural mesothelioma. Nivolumab-ipilimumab improved the survival, however, 30.3% of the patients suffered from grade 3-4 treatment related adverse events (TRAE's) and TRAE's led to discontinuation in 23.0% of all patients. Here, we present the first real-world data of nivolumab plus ipilimumab in patients with malignant mesothelioma treated in two mesothelioma expert centers. METHODS: Clinical data of patients with mesothelioma treated with nivolumab and ipilimumab were prospectively collected. Clinical parameters were obtained every visit, CT scans were evaluated every 12 weeks and adverse events were assessed continuously during the treatment. Data on grade 2-5 TRAE's and activity (overall response rate (ORR), duration of response (DOR), disease control rate (DCR), median progression-free survival (mPFS) and median overall survival (mOS) were reported. RESULTS: Between January 2021 and August 2022, 184 patients were treated with nivolumab plus ipilimumab. The median follow-up was 12.1 months (95 %CI 11.1 - 13.1). Grade 3-4 TRAEs were seen in 27.7 % of the patients and 25.0 % discontinued immunotherapy treatment early because of TRAE's. ORR was 21.7 % (95 % CI 15.7-27.7), median DOR was 5.7 months (IQR 3.2-8.7) and DCR at 12 weeks 56.0 % (95 % CI 48.8-63.2). The mPFS was 5.5 months (95 %CI 4.1-6.9), mOS was 14.1 months (95 % CI 11.1-18.2). CONCLUSIONS: Nivolumab plus ipilimumab had an equal efficacy in a real-world comparable population but also a high risk of TRAE's, leading to discontinuation of treatment in 25% of the patients.

Major pathological response obtained after neoadjuvant chemotherapy combined with dual immunotherapy for malignant pleural mesothelioma: a case report.

Background: Malignant pleural mesothelioma (MPM) is a rare thoracic malignancy with high morbidity and mortality. A combination of systemic therapy and surgery may be a promising modality for the treatment of MPM, but evidence-based medicine is still lacking. Case Description: Here we report a case of MPM. The patient presented to hospital with cough and sputum. After ineffective symptomatic treatment, computed tomography (CT) examination suggested a malignant tumor of pleural origin. Positron emission tomography/computed tomography (PET/CT) examination suggested no lymph node metastasis or distant metastasis. The pathologic diagnosis of MPM was confirmed after CT-guided puncture biopsy. Next, she underwent 3 courses of neoadjuvant chemotherapy combined with dual immunotherapy (carboplatin and pemetrexed combined with anti-CTLA4 and anti-PD-1), resulting in significant tumor shrinkage. After obtaining the patient's consent and completing a preoperative evaluation, we modified the extrapleural pneumonectomy (EPP) and pleurectomy/decortication (P/D) by performing a lower lobe resection and partial pleurectomy of the left lung. Intraoperative rapid frozen pathology suggested that the margins of the tumor were negative and complete resection was achieved. The postoperative pathology report showed 10% residual viable tumor, so the major pathological response (MPR) was achieved after treatment. Conclusions: MPM might respond well to neoadjuvant chemotherapy and dual immunotherapy, improving the probability of complete surgical resection and attaining an encouraging pathologic response.

Malignant Mesothelioma: Overcoming Diagnostic Hurdles.

Malignant pleural mesothelioma, an aggressive neoplasm frequently linked to asbestos exposure, is often detected at an advanced stage. This report details the case of a 58-year-old mason who presented with left-sided chest pain, and shortness of breath, accompanied by weight loss for a month. A positron emission tomography (PET) scan revealed increased uptake along the pleural surface, as well as in several mediastinal lymph nodes and the left supraclavicular lymph node. Thoracoscopy revealed the presence of multiple nodules on the costal pleura. Despite repeated negative results from pleural effusion cytology, cell block analysis, and pleural biopsies, the diagnosis of malignant mesothelioma (MM) was ultimately established through an ultrasound-guided (USG) biopsy of the left supraclavicular lymph node, with immunohistochemical confirmation using calretinin.

The genetic susceptibility in the development of malignant pleural mesothelioma: somatic and germline variants, clinicopathological features and implication in practical medical/surgical care: a narrative review.

Background and Objective: Malignant pleural mesothelioma (MPM) is a very aggressive primary tumor of the pleura whose main risk factor is exposure to asbestos. However, only a minority of exposed people develops MPM and the incidence of MPM cases without an apparent association with asbestos exposure has been increasing in recent years, suggesting that genetic predisposing factors may play a crucial role. In addition, several studies reported familial cases of MPM, suggesting that heredity may be an important and underestimated feature in MPM development. Several candidate genes have been associated with a predisposition to MPM and most of them play a role in DNA repair mechanisms: overall, approximately 20% of MPM cases may be related to genetic predisposition. A particular category of patients with high susceptibility to MPM is represented by carriers of pathogenic variants in the BAP1 gene. Germline variants in BAP1 predispose to the development of MPM following an autosomal dominant pattern of inheritance in the familial cases. MPMs in these patients are significantly less aggressive, and patients require a multidisciplinary approach that involves genetic counseling, medical genetics, pathology, surgical, medical, and radiation oncology expertise. In the present narrative review, we presented a comprehensive overview of genetic susceptibility in the development of MPM. Methods: The narrative review is based on a selective literature carried out in PubMed in 2023. Inclusion criteria were original articles in English language, and clinical trials (randomized, prospective, or retrospective). Key Content and Findings: We summarized the somatic and germline variants and the differences in terms of clinicopathological features and prognosis between gene-related MPM (GR-MPM) and asbestos-related MPM (AR-MPM). We also discussed the indications for screening, genetic testing, and surveillance of patients with BAP1 germline variants. Conclusions: In this narrative review, we have emphasized that the BAP1 gene's harmful germline variations are inherited in an autosomal dominant manner in familial cases. MPMs in individuals with these variations are less severe, and their medical care necessitates a collaborative effort. Additionally, we have outlined the current therapeutic prospects for MPM, including the possibility of gene-specific therapy, which is currently promising but still requires clinical validation.

Challenging the Norm: Occurrence of Synchronous Pleural and Peritoneal Mesothelioma in a Female Patient.

Here, we present a unique case involving a female patient in her 40s with synchronous malignant pleural and peritoneal mesothelioma, despite lacking a history of asbestos exposure. The patient's initial symptoms included dyspnoea, chest pain, cough, fever, appetite loss, and weight loss over a month. Clinical evaluation led to the identification of right-sided pleural effusion, prompting consideration of differential diagnoses, such as tubercular or malignant pleural effusion. A thoracoscopy-guided biopsy, followed by histopathological examination and immunohistochemical staining, confirmed the diagnosis of mesothelioma. Chemotherapy was initiated as part of the treatment plan. The prognosis for this condition is generally bad; however, unusual cases of extended survival have been documented. The complexities of our case underscore the critical necessity for a thorough and aggressive evaluation of pleural effusion cases to unveil rare underlying causes, such as mesothelioma.

A deep learning-based model (DeepMPM) to help predict survival in patients with malignant pleural mesothelioma.

Background: Malignant pleural mesothelioma (MPM) is a rare disease with limited treatment and poor prognosis, and a precise and reliable means to predicting MPM remains lacking for clinical use. Methods: In the population-based cohort study, we collected clinical characteristics from the Surveillance, Epidemiology, and End Results (SEER) database. According to the time of diagnosis, the SEER data were divided into 2 cohorts: the training cohort (from 2010 to 2016) and the test cohort (from 2017 to 2019). The training cohort was used to train a deep learning-based predictive model derived from DeepSurv theory, which was validated by both the training and the test cohorts. All clinical characteristics were included and analyzed using Cox proportional risk regression or Kaplan-Meier curve to determine the risk factors and protective factors of MPM. Results: The survival model included 3,130 cases (2,208 in the training cohort and 922 in the test cohort). As for model's performance, the area under the receiver operating characteristics curve (AUC) was 0.7037 [95% confidence interval (CI): 0.7030-0.7045] in the training cohort and 0.7076 (95% CI: 0.7067-0.7086) in the test cohort. Older age; male sex, sarcomatoid mesothelioma; and T4, N2, and M1 stage tended to be the risk factors for survival. Meanwhile, epithelioid mesothelioma, surgery, radiotherapy, and chemotherapy tended to be the protective factors. The median overall survival (OS) of patients who underwent surgery combined with radiotherapy was the longest, followed by those who underwent a combination of surgery, radiotherapy, and chemotherapy. Conclusions: Our deep learning-based model precisely could predict the survival of patients with MPM; moreover, multimode combination therapy might provide more meaningful survival benefits.

Induction of metallothionein expression by supplementation of zinc induces resistance against platinum-based treatment in malignant pleural mesothelioma.

Background: Malignant pleural mesothelioma (MPM) is an aggressive tumor with a dismal prognosis. Currently, multimodality treatment including chemotherapy with cisplatin or carboplatin in combination with pemetrexed offers the best options. Detoxification of heavy metals in the cell by metallothioneins (MT) is associated with early failure to platin-based chemotherapy. The induction of MTs gene expression or its enzyme results in saturation by exposure to metal ions such as zinc or cadmium. Its therapeutically effect is still not analyzed in depth. Methods: In our study, we investigated three MPM cell lines and one fibroblast cell line in the course of cisplatin treatment and supplementation of zinc. Cell state analyses via an enzyme-activity based assay were performed. With this, we were able to analyze apoptosis, necrosis and viability of cells. Additionally, we tested treated cells for changes in metallothionein IIA (MT2A) expression by using quantitative realtime polymerase chain reaction. Results: Zinc supplementation induces gene expression of MT2A. Overall, a zinc dose-dependent induction of apoptosis under platin-based treatment could be observed. This effect could be verified in all analyzed cell lines in varying intensity. Conclusions: MT expression is induced by zinc in a dose-dependent manner and inhibits a successful cisplatin therapy. Therefore, heavy metal exposure during cisplatin therapy, e.g., via cigarette smoke, might be an important factor. This should be considered in further therapeutic approaches.

Modern Malignant Mesothelioma Manifestation.

Malignant pleural mesothelioma (MPM) involves the uncontrolled growth of mesothelial cells that form the lining of pleural serous layers. MPM has been linked with asbestos exposure in mining and manufacturing occupations with an unforgiving prognosis of 4-18 months. In this case report, we present a 56-year-old male with a significant past medical history of hypertension, hyperlipidemia, hepatic steatosis, and ulcerative colitis who presented to the emergency department for worsening cough, eight-pound weight loss over the previous year, night sweats, and fatigue. The patient was admitted due to right pleural effusion with lower lobe collapse seen on imaging; upon diagnostic workup including pleural biopsy, results were consistent with malignant mesothelioma of the epithelioid type. Over the course of six months post-diagnosis, the patient underwent multiple hospital admissions due to acute hypoxic respiratory failure from the segmental left upper lobe and subsegmental right upper lobe pulmonary emboli, recurrent pleural effusion, and anemia. Given the aggressive nature of MPM, the patient was determined not to be a surgical candidate and underwent palliative chemotherapy sessions until his passing. As the patient worked in heating/ventilation/air conditioning with asbestos exposure, taking a full occupational history was crucial. MPM is relatively rare; however, the incidence has increased over the last decade due to tumor development lag time post-asbestos exposure and an increase in do-it-yourself projects. There is no cure for MPM. Multimodal treatment approaches with surgery, chemotherapy, radiotherapy, and immunotherapy have been noted in the literature.

Pleural Mesothelioma: A Rapid Evolution of an Indolent Disease.

Mesothelioma is a rare and insidious neoplasm and is characterized by its highly malignant and aggressive nature. The most common etiology is asbestos exposure, but there are some reports without known asbestos exposure and other factors leading to malignant pleural mesothelioma (MPM). Here, we present the case of a 58-year-old woman with pleuritic chest pain, dyspnea, and fever on presentation to the emergency department (ED), which caused several admissions to the ED in 20 days. The patient was then admitted to the internal medicine department with a diagnosis of community-acquired pneumonia with parapneumonic effusion. During hospitalization, a positron emission tomography (PET) scan, thoracic computed tomography (CT), and pleural biopsy were performed and a final diagnosis of malignant epithelioid pleural mesothelioma was made. Six weeks after the onset of symptoms, the patient presented with an exponential disease progression, dying two months after the diagnosis, despite the initiation of chemotherapy. MPM remains a diagnostic and therapeutic challenge with a very poor prognosis. However, studies show that mesothelioma patients who undergo treatment live at least twice as long as patients who do not receive treatment. This case report is particularly significant because, although it was epithelioid mesothelioma, multiple solid masses were noted on CT and the patient exhibited rapid disease progression, dying a few weeks after starting treatment.

Does hyperthermic povidone-iodine lavage increase the apoptotic rate of residual cancer cell in patients with malignant pleural mesothelioma?-a prospective pilot study.

Background: Malignant pleural mesothelioma (MPM) is an incurable, late presenting primary cancer, conferring a survival of 8-14 months. Different intrapleural treatments have been tested as part of a multimodality approach to treat a select group of patients with limited disease, increasing survival. Recently, povidone-iodine has been shown to induce apoptosis in microscopic tumour cells in vitro, with no reported complications. This is the first in vivo study assessing the apoptotic rate caused by intraoperative hyperthermic betadine lavage using routine immunohistochemistry combined with transmission electron microscopy (TEM). Methods: We included surgically fit patients aged >18, undergoing minimally invasive video-assisted thoracoscopic surgery (VATS) pleural biopsy between December 2016 and February 2018, for confirmed or presumed pleural malignancy. Parietal pleural biopsies were obtained at 7.5, 15 and 30 minutes after hyperthermic betadine lavage, and compared to pre-lavage biopsy samples, for apoptotic changes. Viable tumour samples underwent histological, immunohistochemical and ultrastructural analysis as well as TEM for features of apoptosis. Results: N=6. Median age was 76 years. Median overall survival was 26.7 months. There was no statistical impact on survival of side of disease (left vs. right). There was no significant difference in expressions of markers of apoptotic index pre and post betadine treatment upon immunohistochemical analysis. There was no discernible effect on morphological features of apoptosis seen with betadine treatment, on TEM analysis. No side effects were identified post betadine lavage. Conclusions: Although hyperthermic betadine lavage is a safe antiseptic solution with no toxicity when performed intraoperatively, it confers no effect on apoptotic rate or necrosis. It is therefore unlikely that hyperthermic betadine lavage will have an impact on reducing the microscopic residual disease after pleurectomy decortication and enhancing survival.