Consensus Report of the 2015 Weinman International Conference on Mesothelioma

DHEA-S, Androstenedione, 17-β-estradiol signature as novel biomarkers for early prediction of risk of malignant pleural mesothelioma linked to asbestos-exposure: A preliminary investigation

17-β-estradiol, involved in mesothelioma pathogenesis, and its precursors were explored as potential biomarkers for the early diagnosis of mesothelioma. Using enzyme-linked immunosorbent assay(ELISA) for 17-β-estradiol and ultra-high performance liquid chromatography/tandem mass spectrometry(UHPLC-MS/MS) for 19 17-β-estradiol precursors, a comprehensive analysis of 20steroid hormones was conducted in the serum of mesothelioma patients(n=67), asbestos-exposed healthy subjects(n=39), and non-asbestos-exposed healthy subjects(n=35). Bioinformatics analysis explored three potential serum biomarkers: 17-β-estradiol, DHEA-S, and androstenedione. The results revealed significant differences in 17-β-estradiol levels between mesothelioma patients and both non-asbestos-exposed and asbestos-exposed healthy subjects. No significant variations in serum 17-β-estradiol levels were observed among mesothelioma patients at different stages, suggesting its potential as an early diagnostic marker. 17-β-estradiol levels were similar in mesothelioma patients with environmental and occupational asbestos exposure, while males with occupational asbestos exposure exhibited significantly higher levels of 17-β-estradiol compared to females. Significant reduction in androstenedione and an increase in DHEA-S were observed in asbestos-exposed individuals compared to non-asbestos-exposed individuals. The analysis of DHEA-S-androstenedione-17-β-estradiol signature score showed an increase in asbestos-exposed individuals and mesothelioma patients compared to non-asbestos-exposed individuals, and this score effectively distinguished between the groups. The Cancer Genome Atlas data was utilized to analyze the expression of 5-α-reductase1 and hydroxysteroid-17β-dehydrogenase2 genes. The findings indicated that mesothelioma patients with elevated gene values for 5-α-reductase1 and hydroxysteroid-17β-dehydrogenase2 have a worse or better prognosis on overall survival, respectively. In conclusion, this study suggests 17-β-estradiol, DHEA-S, and androstenedione as biomarkers for mesothelioma risk and early diagnosis of mesothelioma in asbestos-exposed individuals, aiding timely intervention and improved care.

Asbestos ban policies and mesothelioma mortality in Greece

BACKGROUND

Malignant mesothelioma is a rare form of cancer that mostly affects the pleura and has a strong link to asbestos exposure. Greece banned the use of asbestos in 2005, however, the public was already aware of this substance in the 1980s. This research aims to present an overview of Greece's mesothelioma age-standardized mortality rates (ASMR) from 1983 to 2019 by age, gender, and geographic region and to determine whether the actions to ban asbestos impacted these rates.

METHODS

Data were retrieved by the Hellenic Statistical Authority (HSA) from death certificates that mentioned mesothelioma as the cause of death from 1983 to 2019 with details on the residence, gender, and age. Statistical analysis was performed using PRISM 6.0 software, a two-way ANOVA test, Trend analysis was conducted using Joinpoint Regression Program 5.0 software. The linear and non-linear model was used to calculate the age-standardized rates of annual percentage change (APC) and its 95% confidential interval (95% CI).

RESULTS

From 1983 to 2019, 850 total mesothelioma deaths were recorded, the majority of whom were males (634). A rate of 74.6% accounts for males and 25.4% for females, and the ratio of Males: Females was 3:1. Males' ASMR and the whole population's ASMR reached their highest levels in 2011 (0.93/100000person-years and 0.53/100000person-years, respectively). To look for potential changes between the first two decades of the 21st century, we compared the mean ASMR of each geographic region in Greece between two different 10-year subperiods (2000-2009 and 2010-2019). Except for Epirus, all regions of Greece had elevated regional ASMRs, particularly in those with the highest asbestos deposits. Notably, the ASMR in Epirus decreased from 0.54/100000person-years (2000-2009) to 0.31/100000person-years (2010-2019). After 2011, the ASMR for men and the general population stabilized. This stability is important since mesothelioma in men is associated with occupational asbestos exposure. The intriguing discovery of a lower ASMR in Epirus emphasizes the need to raise awareness of the condition and implement effective public health measures.

CONCLUSIONS

In Greece, the annual ASMR for males and the whole population reached its highest level in 2011, which is positive and encouraging and may be a sign that the rate will stabilize during the following years. Moreover, this study showed that the actions made in the 1980s regarding public awareness and surveillance directly impacted the decrease in Epirus rates. Future research, continual awareness, information, and recording are needed to monitor the mesothelioma epidemic. The possible benefit of a mesothelioma registry and the epidemiological surveillance of asbestos-related diseases, particularly mesothelioma mortality, need to be addressed.

TRIAL REGISTRATION

Not applicable.

Diffuse Pleural Mesothelioma: Advances in Molecular Pathogenesis, Diagnosis, and Treatment

Diffuse pleural mesothelioma (DPM) is a highly aggressive malignant neoplasm arising from the mesothelial cells lining the pleural surfaces. While DPM is a well-recognized disease linked to asbestos exposure, recent advances have expanded our understanding of molecular pathogenesis and transformed our clinical practice. This comprehensive review explores the current concepts and emerging trends in DPM, including risk factors, pathobiology, histologic subtyping, and therapeutic management, with an emphasis on a multidisciplinary approach to this complex disease.

Expression of stathmin in asbestos-like fibers-induced mesothelioma: A preliminary report

BACKGROUND

Mesothelioma is strongly associated with exposure to asbestos fibers, however, recent studies have also linked exposure to "naturally occurring asbestos" fibers with this disease. Fluoro-edenite, a silicate mineral found in the southeast of Biancavilla (Sicily, Italy), has been identified as a potential risk factor for mesothelioma. Unfortunately, this cancer often has a poor prognosis, and current diagnostic and prognostic biomarkers are inadequate. Histological subtype, gender, and age at diagnosis are the most significant parameters for mesothelioma. Stathmin, a cytosolic protein that regulates cell growth and migration and is overexpressed in many human malignancies, has not yet been linked to mesothelioma survival or clinical-pathological variables.

AIM

The aim of this study was to investigate the immunohistochemical expression of stathmin in ten mesothelioma tissue samples with available clinical and follow-up data.

MATERIAL AND METHODS

Paraffin-embedded tissue samples from ten mesothelioma patients were processed for immunohistochemical analyses to evaluate stathmin expression.

RESULTS

Our findings suggest that stathmin overexpression is associated with shorter overall survival in patients with mesothelioma. Furthermore, stathmin expression was significantly correlated with the survival time of mesothelioma patients.

CONCLUSION

Our results suggest that stathmin expression may serve as a potential prognostic biomarker for mesothelioma. This biomarker could be used to promptly identify patients with poor prognosis and to guide clinicians in the selection of treatment options.

CAMK2D: a novel molecular target for BAP1-deficient malignant mesothelioma

Malignant mesothelioma (MMe) is a rare but aggressive malignancy. Although the molecular genetics of MMe is known, including BRCA1-associated protein-1 (BAP1) gene alterations, the prognosis of MMe patients remains poor. Here, we generated BAP1 knockout (BAP1-KO) human mesothelial cell clones to develop molecular-targeted therapeutics based on genetic alterations in MMe. cDNA microarray and quantitative RT-PCR (qRT-PCR) analyses revealed high expression of a calcium/calmodulin-dependent protein kinase type II subunit delta (CAMK2D) gene in the BAP1-KO cells. CAMK2D was highly expressed in 70% of the human MMe tissues (56/80) and correlated with the loss of BAP1 expression, making it a potential diagnostic and therapeutic target for BAP1-deficient MMe. We screened an anticancer drugs library using BAP1-KO cells and successfully identified a CaMKII inhibitor, KN-93, which displayed a more potent and selective antiproliferative effect against BAP1-deficient cells than cisplatin or pemetrexed. KN-93 significantly suppressed the tumor growth in mice xenografted with BAP1-deficient MMe cells. This study is the first to provide a potential molecular-targeted therapeutic approach for BAP1-deficient MMe.

Asbestos accelerates disease onset in a genetic model of malignant pleural mesothelioma

Hypothesis: Asbestos-driven inflammation contributes to malignant pleural mesothelioma beyond the acquisition of rate-limiting mutations. Methods: Genetically modified conditional allelic mice that were previously shown to develop mesothelioma in the absence of exposure to asbestos were induced with lentiviral vector expressing Cre recombinase with and without intrapleural injection of amosite asbestos and monitored until symptoms required euthanasia. Resulting tumours were examined histologically and by immunohistochemistry for expression of lineage markers and immune cell infiltration. Results: Injection of asbestos dramatically accelerated disease onset and end-stage tumour burden. Tumours developed in the presence of asbestos showed increased macrophage infiltration. Pharmacological suppression of macrophages in mice with established tumours failed to extend survival or to enhance response to chemotherapy. Conclusion: Asbestos-driven inflammation contributes to the severity of mesothelioma beyond the acquisition of rate-limiting mutations, however, targeted suppression of macrophages in established epithelioid mesothelioma showed no therapeutic benefit.

Incidence and mortality from malignant mesothelioma 1982-2020 and relationship with asbestos exposure: the Australian Mesothelioma Registry

OBJECTIVES

Malignant mesothelioma is an uncommon cancer associated with asbestos exposure, predominantly occupational. Asbestos has been banned in Australia since 2003 but mesothelioma has a long latency and incident cases continue to present. The Australian Mesothelioma Registry was incepted to collect systematic data about incidence and mortality alongside asbestos exposure.

METHODS

Benefiting from the Australian national system of cancer notification, all incident cases of mesothelioma in all states and territories are fast-tracked and notified regularly. Notified patients are contacted asking for consent to collect exposure information, initially by postal questionnaire and subsequently by telephone interview. Age-standardised annual incidence rates and mortality rates were calculated. Asbestos exposure was categorised as occupational, non-occupational, neither or, both; and as low, or high, probability of exposure.

RESULTS

Mesothelioma incidence appears to have peaked. The age-standardised incidence rates have declined steadily since the early 2000s (peaking in males at 5.9/100 000 and in all-persons at 3.2/100 000), driven by rates in males, who comprise the majority of diagnosed cases. Rates in women have remained fairly stable since that time. Age-standardised mortality rates have followed similar trends. Mesothelioma remains the most common in those aged over 80 years. Nearly all (94%) cases were linked with asbestos exposure (78% occupational in men; 6.8% in women).

CONCLUSIONS

With effective control of occupational asbestos use, the decline in age-standardised incidence and death rates has occurred. Incidence rates among women, in whom occupational asbestos exposure is rarely detectable, remain unchanged, pointing to the role of household and /or environmental asbestos exposure.

The Rocky Road from Preclinical Findings to Successful Targeted Therapy in Pleural Mesothelioma

Pleural mesothelioma (PM) is a rare and aggressive disease that arises from the mesothelial cells lining the pleural cavity. Approximately 80% of PM patients have a history of asbestos exposure. The long latency period of 20-40 years from the time of asbestos exposure to diagnosis, suggests that multiple somatic genetic alterations are required for the tumorigenesis of PM. The genomic landscape of PM has been characterized by inter- and intratumor heterogeneity associated with the impairment of tumor suppressor genes such as CDKN2A, NF2, and BAP1. Current systemic therapies have shown only limited efficacy, and none is approved for patients with relapsed PM. Advances in understanding of the molecular landscape of PM has facilitated several biomarker-driven clinical trials but so far, no predictive biomarkers for targeted therapies are in clinical use. Recent advances in the PM genetics have provided optimism for successful molecular strategies in the future. Here, we summarize the molecular mechanism underlying PM pathogenesis and review potential therapeutic targets.

Malignant Pleural Mesothelioma: Current Understanding of the Immune Microenvironment and Treatments of a Rare Disease

Simple Summary

Malignant pleural mesothelioma is a rare disease with an annual incidence of around 3000 cases a year in the United States. Most cases are caused by asbestos exposure, with a latency period of up to 40 years but overall survival of approximately only 6–12 months after the time of diagnosis. Often, the treatment is multimodal and consists of surgery, chemotherapy, and radiation. While the survival benefit of treatment is impactful, overall prolongation remains marginal. Nevertheless, the advent of new treatment approaches involving the interactions of targeted immune therapies and the tumor microenvironment appear to offer some promise. Furthering our understanding of these complex interactions in conjunction with the host immune system will likely prove to be pivotal in advancing current treatment options for malignant pleural mesothelioma.

Abstract

Malignant pleural mesothelioma is a rare disease with an annual incidence of around 3000 cases a year in the United States. Most cases are caused by asbestos exposure, with a latency period of up to 40 years. Pleural mesothelioma is an aggressive disease process with overall survival of roughly 6–12 months after the time of diagnosis. It is divided into three subtypes: epithelioid, mixed type, and sarcomatoid type, with the epithelioid subtype having the best overall survival. Often, the treatment is multimodality with surgery, chemotherapy, and radiation. The survival benefit is improved but remains marginal. New treatment options involving targeted immune therapies appear to offer some promise. The tumor microenvironment is the ecosystem within the tumor that interacts and influences the host immune system. Understanding this complex interaction and how the host immune system is involved in the progression of the disease process is important to define and guide potential treatment options for this devastating and rare disease.

Tumor suppressor effect of an antibody on xenotransplanted sarcomatoid mesothelioma cells

BACKGROUND

As mesothelioma generally has an unfavorable prognosis, further advances are needed to improve the outcomes in patients with mesothelioma. In the present study, we generated and characterized a monoclonal antibody that could inhibit mesothelioma cell proliferation in a xenotransplantation mouse model.

METHODS

We generated monoclonal antibodies by immunizing mice with cultured mesothelioma cells. These antibodies were then characterized by immunofluorescence staining, immunohistochemical staining, secondary antibody-drug conjugate assay, antibody inoculation in a xenotransplantation mesothelioma mouse model, and mass spectrometry followed by small interfering RNA (siRNA) analysis. 5' rapid amplification of complementary DNA ends followed by sequencing was performed to deduce the amino acid sequences of the variable regions of the light and heavy chains of AX10.

RESULTS

An IgG2b κ-type AX10 antibody against the cell surface membrane of sarcomatoid mesothelioma cells was generated. AX10 immunoreactivity was detected in 12 out of 22 different mesothelioma tissue specimens, but there was little AX10 immunoreactivity in a normal human tissue array. AX10 decreased Matrigel invasion by MPM-1 cells but did not affect cell proliferation. Notably, AX10 significantly inhibited the proliferation of MPM-1 cells xenotransplanted into Severe combined immunodeficiency-Nonobese diabetic mice. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry followed by siRNA silencing indicated that AX10 reacted to a unique alternatively spliced isoform of sarcolemma-associated protein. AX10 is composed of as yet unregistered amino acid sequences in its variable region.

CONCLUSIONS

AX10 could have therapeutic potential for patients with sarcomatoid mesothelioma.

Fibrous Ferrierite from Northern Italy: Mineralogical Characterization, Surface Properties, and Assessment of Potential Toxicity

Nowadays, fibrous minerals pose as significant health hazards to humans, and exposure to these fibers can lead to the development of severe pulmonary diseases. This work investigated the morphology, crystal structure, chemistry, and surface activity of fibrous ferrierite recently found in northern Italy through an integrated approach using scanning electron microscopy–energy dispersive spectroscopy, electron microprobe, inductively coupled plasma atomic emission spectrometry, X-ray powder diffraction, and electron paramagnetic resonance. Our results show that a notable amount of ferrierite fibers are breathable (average length ~22 µm, average diameter 0.9 µm, diameter-length ratio >> 1:3) and able to reach the alveolar space (average Dae value 2.5 μm). The prevailing extra-framework cations are in the Mg > (Ca ≈ K) relationship, R is from 0.81 to 0.83, and the Si/Al ratio is high (4.2–4.8). The <T-O> bond distances suggest the occurrence of some degree of Si,Al ordering, with Al showing a site-specific occupation preference T1 > T2 > T3 > T4. Ferrierite fibers show high amounts of adsorbed EPR probes, suggesting a high ability to adsorb and interact with related chemicals. According to these results, fibrous ferrierite can be considered a potential health hazard, and a precautionary approach should be applied when this material is handled. Future in vitro and in vivo tests are necessary to provide further experimental confirmation of the outcome of this work.

Aurora Kinase A as a Diagnostic and Prognostic Marker of Malignant Mesothelioma

Background

Malignant mesothelioma (MM) is a highly aggressive cancer with a poor prognosis. Despite the use of several well-known markers, the diagnosis of MM is still challenging in some cases. we applied bioinformatics to identify key genes and screen for diagnostic and prognostic markers of MM.

Methods

The expression profiles of GSE2549 and GSE112154 microarray datasets from the Gene Expression Omnibus database contained 87 cases of MM tissue and 8 cases of normal mesothelial tissue in total. The GEO2R tool was used to detect differentially expressed genes (DEGs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs were performed using DAVID Bioinformatics Resources. The DEGs protein-protein interaction networks were constructed from the STRING database. Cytoscape was used to identify significant modules and hub genes. The GEPIA database was used to explore relationships between hub genes and prognosis of MM. Immunohistochemistry was used to analyze protein expression in tissue microarrays with 47 Chinese MM tissues. Statistical analyses diagnostic and prognostic values.

Results

346 DEGs were identified: 111 genes upregulated, and 235 downregulated. GO analysis showed that the primary biological processes of these DEGs were cell adhesion, leukocyte migration, and angiogenesis. The main cellular components included the extracellular space, extracellular exosome, and extracellular region. The molecular functions were integrin binding, heparin binding, and calcium ion binding. KEGG pathway analysis showed that DEGs are primarily involved in PPAR signaling pathway, extracellular matrix–receptor interactions, and regulation of lipolysis in adipocytes. Survival analysis showed that seven genes—AURKA, GAPDH, TOP2A, PPARG, SCD, FABP4, and CEBPA—may be potential prognostic markers for MM. Immunohistochemical studies showed that Aurora kinase A (AURKA gene encode, Aurora-A) and GAPDH were highly expressed in MM tissue in comparison with normal mesothelial tissue. Kaplan-Meier analysis confirmed a correlation between Aurora-A protein expression and overall survival but did not confirm a correlation with GAPDH. The receiver operating characteristic curves of Aurora-A protein expression suggested acceptable accuracy (AUC = 0.827; 95% CI [0.6686 to 0.9535]; p = 0.04). The sensitivity and specificity of Aurora-A were 83.33% and 77.78%, respectively.

Conclusion

Aurora-A could be an optimal diagnostic biomarker and a potential prognostic marker for MM.

Incidence, mortality and survival in malignant pleural mesothelioma before and after asbestos in Denmark, Finland, Norway and Sweden

Background

Malignant pleural mesothelioma (MPM) is a rare but fatal cancer, which is largely caused by exposure to asbestos. Reliable information about the incidence of MPM prior the influence of asbestos is lacking. The nationwide regional incidence trends for MPM remain poorly characterized. We use nationwide MPM data for Denmark (DK), Finland (FI), Norway (NO) and Sweden (SE) to assess incidence, mortality and survival trends for MPM in these countries.

Methods

We use the NORDCAN database for the analyses: incidence data were available from 1943 in DK, 1953 in FI and NO and 1958 in SE, through 2016. Survival data were available from 1967 through 2016. World standard population was used in age standardization.

Results

The lowest incidence that we recorded for MPM was 0.02/100,000 for NO women and 0.05/100,000 for FI men in 1953–57, marking the incidence before the influence of asbestos. The highest rate of 1.9/100,000 was recorded for DK in 1997. Female incidence was much lower than male incidence. In each country, the male incidence trend for MPM culminated, first in SE around 1990. The regional incidence trends matched with earlier asbestos-related industrial activity, shipbuilding in FI and SE, cement manufacturing and shipbuilding in DK and seafaring in NO. Relative 1-year survival increased from about 20 to 50% but 5-year survival remained at or below 10%.

Conclusion

In the Nordic countries, the male incidence trends for MPM climaxed and started to decrease, indicating that the prevention of exposure was beneficial. Survival in MPM has improved for both sexes but long-term survival remains dismal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08913-2.

Current evidence and future perspectives of immune-checkpoint inhibitors in unresectable malignant pleural mesothelioma

Platinum-based chemotherapy is commonly used as the standard first-line treatment for unresectable malignant pleural mesothelioma (MPM). However, in recent times, immune-checkpoint inhibitors (ICIs) have led to a paradigm shift. Herein, we review relevant literature and ongoing trials of ICIs used as both first-line and salvage therapies. Specifically, in the Japanese single-arm, phase II trial, the MERIT trial, nivolumab, an antiprogrammed cell death 1 (PD-1) antibody showed favorable efficacy when used as a salvage therapy. Currently, multiple ICI monotherapy or combination therapy trials have been conducted, which could provide further evidence. Among available ICIs, the anti-PD-1 antibody is promising for unresectable MPM, despite the limited efficacy of anti-CTLA4 monotherapy. Ongoing studies will further confirm the potential efficacy of ICIs for MPM, as observed across other malignancies. It is also crucial to identify any clinically useful predictive biomarkers that could reveal ICIs with maximal effects in MPM.

Histologically Diverse BAP1-Deficient Melanocytic Tumors in a Patient With BAP1 Tumor Predisposition Syndrome

BRCA1-associated protein-1 (BAP1)-deficient cutaneous tumors are common in patients with BAP1 tumor predisposition syndrome, frequently presenting before other associated neoplasms, and can serve as an early marker to identify individuals with this disease. The typical lesions are dermal based and composed of a combination of larger epithelioid melanocytes with abundant glassy cytoplasm and smaller cells resembling those of a conventional nevus. There is often a component of interspersed lymphocytes. However, BAP1-deficient melanocytic tumors can show a spectrum of histologic appearances, ranging from lesions with pure epithelioid, pure conventional nevus, or rhabdoid cells and tumors with an intraepidermal component. To demonstrate such morphologic variation, we present a case of a 50-year-old woman with multiple histologically diverse BAP1-deficient melanocytic tumors and germline BAP1 mutation, identified after a diagnosis of pleural mesothelioma. We also discuss the pathogenesis and potential histopathological and clinical indications of germline versus sporadic etiology in the assessment of BAP1-deficient melanocytic tumors.

The Updating of Biological Functions of Methyltransferase SETDB1 and Its Relevance in Lung Cancer and Mesothelioma

SET domain bifurcated 1 (SETDB1) is a histone H3 lysine 9 (H3K9) methyltransferase that exerts important effects on epigenetic gene regulation. SETDB1 complexes (SETDB1-KRAB-KAP1, SETDB1-DNMT3A, SETDB1-PML, SETDB1-ATF7IP-MBD1) play crucial roles in the processes of histone methylation, transcriptional suppression and chromatin remodelling. Therefore, aberrant trimethylation at H3K9 due to amplification, mutation or deletion of SETDB1 may lead to transcriptional repression of various tumour-suppressing genes and other related genes in cancer cells. Lung cancer is the most common type of cancer worldwide in which SETDB1 amplification and H3K9 hypermethylation have been indicated as potential tumourigenesis markers. In contrast, frequent inactivation mutations of SETDB1 have been revealed in mesothelioma, an asbestos-associated, locally aggressive, highly lethal, and notoriously chemotherapy-resistant cancer. Above all, the different statuses of SETDB1 indicate that it may have different biological functions and be a potential diagnostic biomarker and therapeutic target in lung cancer and mesothelioma.

When the Diagnosis of Mesothelioma Challenges Textbooks and Guidelines

The diagnosis of malignant mesothelioma (MPM) does not pose difficulties when presenting with usual clinico-radiologic features and morphology. Pathology textbooks and national/international guidelines generally describe the findings of classic MPM, underlining common clinical presentation, the gold standard of sampling techniques, usual morphologic variants, immunohistochemical results of several positive and negative primary antibodies in the differential diagnosis, and the role of novel molecular markers. Nevertheless, MPM often does not follow the golden rules in routine practice, while the literature generally does not sufficiently emphasize unusual features of its manifestation. This gap may potentially create problems for patients in sustaining a difficult diagnosis of MPM in clinical practice and during legal disputes. Indeed, the guidelines accidentally tend to favor the job of lawyers and pathologists defending asbestos-producing industries against patients suffering from MPM characterized by uncommon features. The current review is aimed at underlining the wide spectrum of clinical and radiological presentation of MPM, the possibility to consistently use cytology for diagnostic intent, the aberrant immunohistochemical expression using so-called specific negative and positive primary antibodies, and finally proposing some alternative and more unbiased approaches to the diagnosis of MPM.

Epidemiology, diagnosis and treatment of the malignant pleural mesothelioma, a narrative review of literature

The malignant pleural mesothelioma is a very aggressive tumor which is arising from mesothelial cells and is associated with asbestos exposure. It is a heterogeneous cancer that shows a complex pattern of molecular changes, including genetic, chromosomic, and epigenetic abnormalities. The malignant pleural mesothelioma is characterized by a silent and slow clinical progression with an average period of 20–40 years from the asbestos exposure phase to the start of the symptoms. Unfortunately, to date, the therapeutic options are very limited, especially if the tumor is detected late. This narrative review provides an extended overview of the present evidence in the literature regarding the epidemiology, diagnostic pathways and treatment approaches of the malignant pleural mesothelioma. The treatment of mesothelioma has evolved slowly over the last 20 years not only from a surgical point of view but also radiotherapy, chemotherapy and immunotherapy play nowadays a key role. Several surgical strategies are available ranging from extrapleural pneumonectomy to cytoreductive surgery but a multidisciplinary approach seems to be mandatory because a single approach has not proved to date to be resolutive. New non-surgical treatment options appear to be promising but the results have to be taken in account with caution because clear evidence with high-quality studies is still lacking

In vitro toxicity of fibrous glaucophane

The health hazard represented by the exposure to asbestos may also concern other minerals with asbestos-like crystal habit. One of these potentially hazardous minerals is fibrous glaucophane. Fibrous glaucophane is a major component of blueschist rocks of California (USA) currently mined for construction purposes. Dust generated by the excavation activities might potentially expose workers and the general public. The aim of this study was to determine whether fibrous glaucophane induces in vitro toxicity effects on lung cells by assessing the biological responses of cultured human pleural mesothelial cells (Met-5A) and THP-1 derived macrophages exposed for 24 h and 48 h to glaucophane fibres. Crocidolite asbestos was tested for comparison. The experimental configuration of the in vitro tests included a cell culture without fibres (i.e., control), cell cultures treated with 50 μg/mL (i.e., 15.6 μg/cm²) of crocidolite fibres and 25-50-100 μg/mL (i.e., 7.8-15.6-31.2 μg/cm²) of glaucophane fibres. Results showed that fibrous glaucophane may induce a decrease in cell viability and an increase in extra-cellular lactate dehydrogenase release in the tested cell cultures in a concentration dependent mode. Moreover, it was found that fibrous glaucophane has a potency to cause oxidative stress. The biological reactivity of fibrous glaucophane confirms that it is a toxic agent and, although it apparently induces lower toxic effects compared to crocidolite, exposure to this fibre may be responsible for the development of lung diseases in exposed unprotected workers and population.

Bridging the gap between toxicity and carcinogenicity of mineral fibres by connecting the fibre crystal-chemical and physical parameters to the key characteristics of cancer

Airborne fibres and particularly asbestos represent hazards of great concern for human health because exposure to these peculiar particulates may cause malignancies such as lung cancer and mesothelioma. Currently, many researchers worldwide are focussed on fully understanding the patho-biological mechanisms leading to carcinogenesis prompted by pathogenic fibres. Along this line, the present work introduces a novel approach to correlate how and to what extent the physical/crystal-chemical and morphological parameters (including length, chemistry, biodurability, and surface properties) of mineral fibres cause major adverse effects with an emphasis on asbestos. The model described below conceptually attempts to bridge the gap between toxicity and carcinogenicity of mineral fibres and has several implications: 1) it provides a tool to measure the toxicity and pathogenic potential of asbestos minerals, allowing a quantitative rank of the different types (e.g. chrysotile vs. crocidolite); 2) it can predict the toxicity and pathogenicity of "unregulated" or unclassified fibres; 3) it reveals the parameters of a mineral fibre that are active in stimulating key characteristics of cancer, thus offering a strategy for developing specific cancer prevention strategies and therapies. Chrysotile, crocidolite and fibrous glaucophane are described here as mineral fibres of interest.

Expression of Calretinin, Marker of Mesothelial Differentiation, in Pancreatic Ductal Adenocarcinoma: A Potential Diagnostic Pitfall

OBJECTIVE

Pancreatic ductal adenocarcinoma is one of the most common causes of "peritoneal carcinomatosis" and has an insidious growth pattern. Thus, it falls into the differential diagnosis of other peritoneal malignancies including malignant mesothelioma. Recently, we have encountered an undifferentiated pancreatic carcinoma presenting with peritoneal disease and exhibiting immunoreactivity to calretinin, mimicking mesothelioma. In this study, we explored the incidence of calretinin expression in pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Calretinin immunohistochemical staining was performed on the tissue microarrays (TMAs), which were created using three 0.6 mm diameter punches per tumor (n=113). Distribution and intensity of expression were evaluated.

RESULTS

The TMAs contained 86 well/moderately differentiated and 27 poorly differentiated/undifferentiated carcinomas. Calretinin was positive in nine tumors (8%); six with diffuse and strong staining, three with focal and/or weak staining. The incidence of calretinin expression was 15% in poorly differentiated/undifferentiated carcinomas (vs. 6% in well/moderately differentiated carcinomas, p=0.03).

CONCLUSIONS

Pancreatic ductal adenocarcinomas, especially when poorly differentiated/undifferentiated, may be diffusely and strongly positive for calretinin creating a potential diagnostic challenge with malignant mesothelioma. Therefore, caution should be exercised when using this marker to explore a diagnosis of malignant mesothelioma. Tumors expressing calretinin without other mesothelial markers should prompt a careful evaluation of the morphologic and immunohistochemical features to exclude other malignancies. If the diagnosis of pancreatic ductal adenocarcinoma is considered, ductal differentiation can be demonstrated by using additional immunohistochemical markers such as mucin-related glycoproteins (MUC1, MUC5AC) and/or oncoproteins (CEA, B72.3, CA125).

Challenges in lung and thoracic pathology: molecular advances in the classification of pleural mesotheliomas

The diagnosis and classification of malignant pleural mesothelioma (MPM) is extremely challenging; obtaining an accurate histopathological diagnosis of the different types and subtypes requires expert assessment and suitable biopsies that are not always available, which can leave doctors uncertain about the patient's diagnosis, sometimes resulting in a delay in the start of treatment. In this review, we discuss recent major advances in the molecular characterisation of MPM and their implications for histological classification. We detail what is known of the molecular landscape of MPM at the genomic, transcriptomic, and epigenomic levels, describe the similarities and dissimilarities of the multiple molecular classifications that have been proposed, and provide an overview of the current state of knowledge regarding inter- and intra-tumour heterogeneity. We also highlight the current gaps in knowledge and how addressing them would benefit classification, as well as the patients in general.

Identification of CD24 as a potential diagnostic and therapeutic target for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive malignancy of the pleura that is currently incurable due to the lack of an effective early diagnostic method and specific medication. The CDKN2A (p16) and NF2 genes are both frequently mutated in MPM. To understand how these mutations contribute to MPM tumor growth, we generated NF2/p16 double-knockout (DKO) cell clones using human MeT-5A and HOMC-B1 mesothelial cell lines. Cell growth and migration activities were significantly increased in DKO compared with parental cells. cDNA microarray analysis revealed differences in global gene expression profiles between DKO and parental cells. Quantitative PCR and western blot analyses showed upregulation of CD24 concomitant with increased phosphorylation of AKT, p70S6K, and c-Jun in DKO clones. This upregulation was abrogated by exogenous expression of NF2 and p16. CD24 knockdown in DKO cells significantly decreased TGF-β1 expression and increased expression of E-cadherin, an epithelial-mesenchymal transition marker. CD24 was highly expressed in human mesothelioma tissues (28/45 cases, 62%) and associated with the loss of NF2 and p16. Public data analysis revealed a significantly shorter survival time in MPM patients with high CD24 gene expression levels. These results strongly indicate the potential use of CD24 as a prognostic marker as well as a novel diagnostic and therapeutic target for MPM.

CDKN2A and MTAP Are Useful Biomarkers Detectable by Droplet Digital PCR in Malignant Pleural Mesothelioma: A Potential Alternative Method in Diagnosis Compared to Fluorescence In Situ Hybridisation

Background

The diagnosis of malignant pleural mesothelioma (MPM) can be difficult, in part due to the difficulty in distinguishing between MPM and reactive mesothelial hyperplasia (RMH). The tumor suppressor gene, CDKN2A, is frequently silenced by epigenetic mechanisms in many cancers; in the case of MPM it is mostly silenced via genomic deletion. Co-deletion of the CDKN2A and methylthioadenosine phosphorylase (MTAP) genes has been researched extensively and discovered to be a highly specific characteristic of MPM. Most studies have used FISH to detect the deletion of CDKN2A and IHC for MTAP as a surrogate for this. In this study, we aim to investigate and validate droplet digital PCR (ddPCR) as an emerging alternative and efficient testing method in diagnosing MPM, by particularly emphasizing on the loss of MTAP and CDKN2A.

Methods

This study included 75 formalin fixed paraffin embedded (FFPE) MPM tissue, and 12 normal pleural tissue and 10 RMH as control. Additionally, primary MPM cell lines and normal pleural samples were used as biomarker detection controls, as established in our previous publication. All FFPE specimens were processed to isolate the DNA, that was subsequently used for ddPCR detection of CDKN2A and MTAP. FFPE samples were also analyzed by fluorescence in situ hybridization (FISH) for CDKN2A and MTAP deletion, and for MTAP IHC expression. Concordance of IHC and ddPCR with FISH were studied in these samples.

Results

95% and 82% of cases showed co-deletion of both MTAP and CDKN2A when determined by FISH and ddPCR respectively. ddPCR has a sensitivity of 72% and specificity of 100% in detecting CDKN2A homozygous loss in MPM. ddPCR also has a concordance rate of 92% with FISH in detecting homozygous loss of CDKN2A. MTAP IHC was 68% sensitive and 100% specific for detecting CDKN2A homozygous loss in MPM when these losses were determined by ddPCR.

Conclusion

Our study confirms that MTAP is often co-deleted with CDKN2A in MPM. Our in-house designed ddPCR assays for MTAP and CDKN2A are useful in differentiating MPM from RMH, and is highly concordant with FISH that is currently used in diagnosing MPM. ddPCR detection of these genetic losses can potentially be utilized as an alternative method in the diagnosis of MPM and for the future development of a less-invasive MPM-specific detection technique on MPM tumor tissue DNA.

Update of in vitro, in vivo and ex vivo fluoro-edenite effects on malignant mesothelioma: A systematic review (Review)

Fluoro-edenite (FE), asbestiform fiber found in Biancavilla (Sicily, Italy), presents various characteristics similar to the asbestos group, in particular two fibrous phases tremolite and actinolite. Indeed, epidemiological studies have shown that FE fibers have similar effects to those of asbestos fibers. Such studies have reported a high incidence of malignant mesothelioma (MM), an aggressive neoplasm of the serosal membranes lining the pleural cavity, in individuals residing there due to FE exposure in Biancavilla related to environmental contamination. Evidence has led to the classification of FE as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC). The aim of this systematic review is to compare the results achieved in in vitro, in vivo and ex vivo experimental studies involving FE in order to update the current knowledge on the pathogenesis and molecular mechanisms responsible for FE-mediated MM development as well as the availability of effective biomarkers for MM prevention and diagnosis. This review is focused on the pathophysiological mechanisms mediated by inflammation induced by FE fiber exposure and which are responsible for MM development. This review also discusses the discovery of new diagnostic and prognostic biomarkers for the management of this pathology. It is known that the risk of cancer development increases with chronic inflammation, arising from enhanced reactive oxygen species (ROS) and NO^• production stimulated by the body to remove exogenous agents, causing DNA damage and enhanced signal transduction that may lead to activation of oncogenes. Studies concerning MM biomarker discovery indicate that several biomarkers have been proposed for MM, but mesothelin is the only Food and Drug Administration (FDA)-approved biomarker for MM, with limitations. In recent studies, in silico analysis to identify selected miRNAs highly deregulated in cancer samples when compared with normal control have been developed. This in silico approach could represent an effort in the field of biomarker discovery for MM.

Mutational Profile of Malignant Pleural Mesothelioma (MPM) in the Phase II RAMES Study

Simple Summary

Malignant pleura Mesothelioma (MPM) is an aggressive cancer arising from the mesothelial cells of the pleura. About 80% of mesothelioma cases are linked to asbestos exposure; the remainder may be related to prior chest radiation, genetic predisposition or spontaneous occurrence. Understanding the genetic alterations that drive MPM is critical for successful development of diagnostics, prognostics and personalized therapeutic modalities. Because MPM is rare, genomic studies are limited and have typically involved a small number of samples. The aim of our study was to understand the mutational landscape of MPM. Our analysis identified significantly mutated genes. This study on a rare tumor type will be important for patients “in real life”.

Abstract

Purpose: Malignant pleural mesothelioma (MPM) is an aggressive cancer. Data are not available in prospective trials on correlations between genetic alterations and outcomes of therapies. In this study, we assessed the genetic profile of MPM patients (pts) in tissue samples. Patients and Methods: From December 2016 to July 2018 (end of enrolment), 164 pts were enrolled. We evaluated by targeted sequencing the mutational profile of a panel of 34 genes: ACTB, ACTG1, ACTG2, ACTR1A, BAP1, CDH8, CDK4, CDKN2A, CDKN2B, COL3A1, COL5A2, CUL1, DHFR, GOT1, KDR, KIT, MXRA5, NF2, NFRKB, NKX6-2, NOD2, PCBD2, PDZK1IP1, PIK3CA, PIK3CB, PSMD13, RAPGEF6, RDX, SETDB1, TAOK1, TP53, TXNRD1, UQCRC1, XRCC6. Genetic profiling was correlated with clinical and pathological variables. Results: Overall, 110 pts (67%) from both treatment arms had samples available for molecular analysis. Median age was 63 years (45–81), 25.5% (n = 28) were females, and 74.5% (n = 82) were males. Tumor histotype was 81.8% (n = 90) epithelioid and 18.2% (n = 20) non-epithelioid; 28.5% of the tumors (n = 42) were stage IV, 71.5% (n = 68) were stage III. Targeted sequencing of tissue specimens identified 275 functional somatic mutations in the 34 genes analyzed. The number of mutated genes was positively associated with higher stage and metastatic disease (p = 0.025). RDX (42%), MXRA5 (23%), BAP1 (14%), and NF2 (11%) were the most frequently mutated genes. Mutations in RAPGEF6 (p = 0.03) and ACTG1 (p = 0.02) were associated with the non-epithelioid subtype, and mutations in BAP1 (p = 0.04) were related to progression-free survival (PFS) > 6 months. Conclusions: In the Ramucirumab Mesothelioma clinical trial (RAMES), mutation of the gene BAP1 is related to a prolonged PFS for patients treated with platinum/pemetrexed regimens (p = 0.04).

Mesothelioma Biomarkers: Discovery in Search of Validation

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm that can only be treated successfully when correctly diagnosed and treated early. The asbestos-exposed population is a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. We review recent work with biomarker development in MPM and literature of the last 20 years on the most promising blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms are covered. SMRP is the only validated blood-based biomarker with diagnostic, monitoring and prognostic value. To strengthen development and testing of MPM biomarkers, cohorts for validation must be established by enlisting worldwide collaborations.

Characterization of Fibrous Mordenite: A First Step for the Evaluation of Its Potential Toxicity

In nature, a huge number of unregulated minerals fibers share the same characteristics as asbestos and therefore have potential adverse health effects. However, in addition to asbestos minerals, only fluoro-edenite and erionite are currently classified as toxic/pathogenic agents by the International Agency for Research on Cancer (IARC). Mordenite is one of the most abundant zeolites in nature and commonly occurs with a fibrous crystalline habit. The goal of this paper is to highlight how fibrous mordenite shares several common features with the well-known carcinogenic fibrous erionite. In particular, this study has shown that the morphology, biodurability, and surface characteristics of mordenite fibers are similar to those of erionite and asbestos. These properties make fibrous mordenite potentially toxic and exposure to its fibers can be associated with deadly diseases such as those associated with regulated mineral fibers. Since the presence of fibrous mordenite concerns widespread geological formations, this mineral fiber should be considered dangerous for health and the precautionary approach should be applied when this material is handled. Future in vitro and in vivo tests are necessary to provide further experimental confirmation of the outcome of this work.

Mesothelioma Biomarkers: A Review Highlighting Contributions from the Early Detection Research Network

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm, which can be treated successfully only if correctly diagnosed and treated in early stages. The asbestos-exposed population serves as a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. This review details the recent work with biomarker development in MPM and the contributions of the NCI Early Detection Research Network Biomarker Developmental Laboratory of NYU Langone Medical Center. The literature of the last 20 years was reviewed to comment on the most promising of the blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms as well as novel studies such as "breath testing" are covered. Soluble mesothelin-related proteins (SMRP) have been characterized extensively and constitute an FDA-approved biomarker in plasma with diagnostic, monitoring, and prognostic value in MPM. Osteopontin is found to be a valuable prognostic biomarker for MPM, while its utility in diagnosis is slightly lower. Other biomarkers, such as calretinin, fibulin 3, and High-Mobility Group Box 1 (HMGB1), remain under study and need international validation trials with large cohorts of cases and controls to demonstrate any utility. The EDRN has played a key role in the development and testing of MPM biomarkers by enlisting collaborations all over the world. A comprehensive understanding of previously investigated biomarkers and their utility in screening and early diagnosis of MPM will provide guidance for further future research.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

Malignant Peritoneal Mesothelioma as a Rare Cause of Dyspeptic Complaints and Ascites: A Diagnostic Challenge

Introduction

Malignant peritoneal mesothelioma (MPM) is a rare malignancy of the mesothelial cells in the peritoneum. The best-defined risk factor is asbestos exposure, but germline mutations in BAP1 also increase susceptibility to this tumor. The diagnosis of MPM is challenging since clinical manifestations are often nonspecific.

Case Presentation

We describe a case of MPM in a 53-year-old former construction worker with prior asbestos exposure. The clinical presentation was a 3-month history of dyspeptic complaints. As initial workup, abdominal ultrasound and upper gastrointestinal endoscopy were performed. Chronic gastritis due to Helicobacter pylori was detected, which was promptly treated but without symptom relief. Abdominal ultrasound showed small volume ascites with hyperechogenic foci, which was later confirmed on computed tomography scan showing the presence of peritoneal nodules in the greater omentum and mesentery. A thorough investigation was conducted based on the suspicion of peritoneal carcinomatosis. A non-peritoneal primary tumor was not found. Ascitic cytology and immunocytochemical studies were suggestive of mesothelioma. He underwent exploratory laparotomy and inoperable peritoneal disease was observed. Peritoneal biopsy confirmed epithelioid-type MPM. Systemic therapy was initiated with platinum plus pemetrexed with good response. The last follow-up was 38 months after the diagnosis.

Discussion/Conclusion

The diagnosis of MPM is challenging since it requires a high degree of suspicion. MPM has a poor prognosis. The standard of treatment recommended is cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. For those who are inoperable, systemic therapy with pemetrexed-cisplatin combination is the alternative. Given the infrequency of disease, it is imperative to ensure patient participation in clinical trials with the purpose of treatment standardization.

TGFα Promotes Chemoresistance of Malignant Pleural Mesothelioma

Background: There is no standard chemotherapy for refractory or relapsing malignant pleural mesothelioma (MPM). Our previous reports nevertheless indicated that a combination of an anthracycline (doxorubicin) and a lysine deacetylase inhibitor (valproic acid, VPA) synergize to induce the apoptosis of MPM cells and reduce tumor growth in mouse models. A Phase I/II clinical trial indicated that this regimen is a promising therapeutic option for a proportion of MPM patients. Methods: The transcriptomes of mesothelioma cells were compared after Illumina HiSeq 4000 sequencing. The expression of differentially expressed genes was inhibited by RNA interference. Apoptosis was determined by cell cycle analysis and Annexin V/7-AAD labeling. Protein expression was assessed by immunoblotting. Preclinical efficacy was evaluated in BALB/c and NOD-SCID mice. Results: To understand the mechanisms involved in chemoresistance, the transcriptomes of two MPM cell lines displaying different responses to VPA-doxorubicin were compared. Among the differentially expressed genes, transforming growth factor alpha (TGFα) was associated with resistance to this regimen. The silencing of TGFα by RNA interference correlated with a significant increase in apoptosis, whereas the overexpression of TGFα desensitized MPM cells to the apoptosis induced by VPA and doxorubicin. The multi-targeted inhibition of histone deacetylase (HDAC), HER2 and TGFα receptor (epidermal growth factor receptor/EGFR) improved treatment efficacy in vitro and reduced tumor growth in two MPM mouse models. Finally, TGFα expression but not EGFR correlated with patient survival. Conclusions: Our data show that TGFα but not its receptor EGFR is a key factor in resistance to MPM chemotherapy. This observation may contribute to casting light on the promising but still controversial role of EGFR signaling in MPM therapy.

Analysis of survival of patients with metastatic malignant pleural mesothelioma

AIM

To report the outcomes and prognosis of patients with malignant pleural mesothelioma (MPM) who present with or develop metastases during treatment.

METHODS

This is a retrospective observational study of patients diagnosed with MPM over 7 years. Metastases at presentation or during follow-up were recorded. Multivariate Cox regression was used to evaluate the relationship of clinicopathologic variables and overall survival (OS). Logistic regression was used for propensity score matching of patients to assess chemotherapy treatment effect.

RESULTS

There were 367 patients included with a median age of 71 years (range, 29-91). A total of 69 patients (18%) had metastases: 14 at presentation and 55 during follow-up. Patients presenting with metastases had significantly worse median and 2-year OS compared to those developing metastases during follow-up: 13.3 months (95% confidence interval [CI], 2-24.6 months) and 0% versus 20.2 months (95% CI, 16.7-23.3 months) and 33%, respectively (p = 0.029). Female sex, age >70 years, nonepithelioid histology, and not receiving chemotherapy were independent poor prognostic factors. There was no difference in OS of patients with locally advanced (T4) disease compared to metastatic disease (M1): median OS 10.7 months (95% CI, 5.9-15.6) versus 13.3 months (95% CI, 2-24.6) (p = 0.18), respectively. Following propensity matching, sarcomatoid histology (hazard ratio, 7.86 [95% CI, 3.64-16.95]; p < 0.001) and multiple lines of chemotherapy (hazard ratio, 0.38 [95% CI, 0.19-0.84]; p = 0.015) were significant independent prognostic factors for OS.

CONCLUSIONS

T4 disease carries a similar OS as metastatic MPM. Female sex, advanced age, nonepithelioid histology, and not receiving chemotherapy were independent poor prognostic factors.

BAP1: role in carcinogenesis and clinical implications

BRCA-1 associated protein 1 (BAP1) is a tumor suppressor gene that has been implicated in the pathogenesis of several malignancies and is gaining more recognition as a crucial gene that could be amenable to therapeutic manipulation. There is a growing interest in prevention and establishing cancer screening guidelines in patients with germline BAP1 mutations to aid with early detection and treatment of associated malignancies. We aim to give a concise review of BAP1 and its role in carcinogenesis, the BAP1 cancer predisposition syndrome and discuss clinical implications including suggested screening guidelines, and potential targeted therapeutic options.

SV40 and human mesothelioma

Simian virus 40 (SV40) is a DNA tumor virus capable of infecting and transforming human mesothelial (HM) cells in vitro. Hamsters injected intracardially to expose most tissue types to SV40 preferentially develop mesotheliomas. In humans, asbestos is the main cause of mesothelioma, and asbestos and SV40 are co-carcinogens in transforming HM cells in tissue culture and in causing mesothelioma in hamsters. Laser microdissection experiments conducted in the laboratory of Adi Gazdar demonstrated that SV40 was present specifically in the malignant mesothelioma cells and not in nearby stromal cells. Further experiments demonstrated that SV40 remains episomal in HM cells and astrocytes because of the production of a long antisense RNA that represses viral capsid protein production. Thus, the potent SV40 oncoprotein, T-antigen (Tag), is expressed, but because the capsid proteins are not produced, the cells are not lysed and, instead, become transformed. Together this evidence suggests that SV40 may contribute to the development of mesotheliomas in humans. However, epidemiological evidence to support this hypothesis is lacking. This chapter also summarizes the introduction of SV40, a monkey virus, into the human population as an unrecognized contaminant of early poliovaccines. In addition to mesotheliomas, SV40 now is linked with brain cancers, osteosarcomas, and lymphomas in humans. Explanations are provided for the apparent geographic variations in SV40 prevalence and for controversies about the role of SV40 in human cancer.

Workshop summary: Potential usefulness and feasibility of a US National Mesothelioma Registry

The burden and prognosis of malignant mesothelioma in the United States have remained largely unchanged for decades, with approximately 3200 new cases and 2400 deaths reported annually. To address care and research gaps contributing to poor outcomes, in March of 2019 the Mesothelioma Applied Research Foundation convened a workshop on the potential usefulness and feasibility of a national mesothelioma registry. The workshop included formal presentations by subject matter experts and a moderated group discussion. Workshop participants identified top priorities for a registry to be (a) connecting patients with high-quality care and clinical trials soon after diagnosis, and (b) making useful data and biospecimens available to researchers in a timely manner. Existing databases that capture mesothelioma cases are limited by factors such as delays in reporting, deidentification, and lack of exposure information critical to understanding as yet unrecognized causes of disease. National disease registries for amyotrophic lateral sclerosis (ALS) in the United States and for mesothelioma in other countries, provide examples of how a registry could be structured to meet the needs of patients and the scientific community. Small-scale pilot initiatives should be undertaken to validate methods for rapid case identification, develop procedures to facilitate patient access to guidelines-based standard care and investigational therapies, and explore approaches to data sharing with researchers. Ultimately, federal coordination and funding will be critical to the success of a National Mesothelioma Registry in improving mesothelioma outcomes and preventing future cases of this devastating disease.

A Comparison of Environmental Concerns in Two Disparate Montana and Nevada Communities

Asbestos refers to six fibrous minerals that occur naturally in the environment in the United States and throughout the world. Deposits may be found in soil, rocks, and deposits of other minerals such as vermiculite and talc. These naturally occurring asbestos (NOA) minerals belong to the serpentine and amphibole family of minerals. This chapter reports shared components of community-driven environmental concerns related to exposure to NOA in a rural Montana and a suburban Nevada community. The specific aim is to establish an understanding of the community and community member's primary concern(s) related to NOA in both communities. The knowledge that NOA is commonly found in areas across the United States supports the need for additional research into the health effects of environmental exposure and best-practices to reduce exposure risk while allowing communities to thrive economically.

Redefining malignant pleural mesothelioma types as a continuum uncovers immune-vascular interactions

BACKGROUND

Malignant Pleural Mesothelioma (MPM) is an aggressive disease related to asbestos exposure, with no effective therapeutic options.

METHODS

We undertook unsupervised analyses of RNA-sequencing data of 284 MPMs, with no assumption of discreteness. Using immunohistochemistry, we performed an orthogonal validation on a subset of 103 samples and a biological replication in an independent series of 77 samples.

FINDINGS

A continuum of molecular profiles explained the prognosis of the disease better than any discrete model. The immune and vascular pathways were the major sources of molecular variation, with strong differences in the expression of immune checkpoints and pro-angiogenic genes; the extrema of this continuum had specific molecular profiles: a "hot" bad-prognosis profile, with high lymphocyte infiltration and high expression of immune checkpoints and pro-angiogenic genes; a "cold" bad-prognosis profile, with low lymphocyte infiltration and high expression of pro-angiogenic genes; and a "VEGFR2+/VISTA+" better-prognosis profile, with high expression of immune checkpoint VISTA and pro-angiogenic gene VEGFR2. We validated the gene expression levels at the protein level for a subset of five selected genes belonging to the immune and vascular pathways (CD8A, PDL1, VEGFR3, VEGFR2, and VISTA), in the validation series, and replicated the molecular profiles as well as their prognostic value in the replication series.

INTERPRETATION

The prognosis of MPM is best explained by a continuous model, which extremes show specific expression patterns of genes involved in angiogenesis and immune response.

Mesothelioma: Scientific clues for prevention, diagnosis, and therapy

Mesothelioma affects mostly older individuals who have been occupationally exposed to asbestos. The global mesothelioma incidence and mortality rates are unknown, because data are not available from developing countries that continue to use large amounts of asbestos. The incidence rate of mesothelioma has decreased in Australia, the United States, and Western Europe, where the use of asbestos was banned or strictly regulated in the 1970s and 1980s, demonstrating the value of these preventive measures. However, in these same countries, the overall number of deaths from mesothelioma has not decreased as the size of the population and the percentage of old people have increased. Moreover, hotspots of mesothelioma may occur when carcinogenic fibers that are present in the environment are disturbed as rural areas are being developed. Novel immunohistochemical and molecular markers have improved the accuracy of diagnosis; however, about 14% (high-resource countries) to 50% (developing countries) of mesothelioma diagnoses are incorrect, resulting in inadequate treatment and complicating epidemiological studies. The discovery that germline BRCA1-asssociated protein 1 (BAP1) mutations cause mesothelioma and other cancers (BAP1 cancer syndrome) elucidated some of the key pathogenic mechanisms, and treatments targeting these molecular mechanisms and/or modulating the immune response are being tested. The role of surgery in pleural mesothelioma is controversial as it is difficult to predict who will benefit from aggressive management, even when local therapies are added to existing or novel systemic treatments. Treatment outcomes are improving, however, for peritoneal mesothelioma. Multidisciplinary international collaboration will be necessary to improve prevention, early detection, and treatment.

Scientific Advances and New Frontiers in Mesothelioma Therapeutics

Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer that arises from the mesothelial surface of the pleural and peritoneal cavities, the pericardium, and rarely, the tunica vaginalis. The incidence of MPM is expected to increase worldwide in the next two decades. However, even with the use of multimodality treatment, MPM remains challenging to treat, with a 5-year survival rate of less than 5%. The International Association for the Study of Lung Cancer has gathered experts in different areas of mesothelioma research and management to summarize the most significant scientific advances and new frontiers related to mesothelioma therapeutics.

Mesothelioma mortality within two radiation monitored occupational cohorts

Purpose: The risk of mesothelioma, including cancers of the pleura and peritoneum, was examined within two large cohorts of workers monitored for exposure to ionizing radiation. Methods and materials: Mortality was assessed among 253,632 workers routinely monitored for external radiation, including 30,724 industrial radiographers (IR) at shipyards, 142,583 workers at nuclear power plants (NPP), and 83,441 IR who had not worked at an NPP or shipyard. Follow-up was from 1969 through 2011. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were computed; observed numbers of deaths from mesothelioma (including cancers of the pleura and peritoneum) and asbestosis were compared with numbers expected based on age-, sex-, and calendar year-specific national mortality rates. Job history and quantitative asbestos exposure data were unavailable, but work at a shipyard was taken as a surrogate for the likelihood of exposure. Cox proportional hazards models were used to estimate hazard ratios (HRs) for mesothelioma in relation to estimated cumulative radiation exposure to the lung. Results: The mean duration of follow-up was 25.3 years (max 42 years). The mean cumulative lung dose was 28.6 mGy (7.3% > 250 mGy). Nearly 20% of the workers had died by 2011. A total of 421 mesothelioma deaths were found (75% occurring after 1999) with increased SMRs among workers monitored in shipyards (SMR 9.97; 95% CI 8.50-11.63) and for NPP workers (SMR 5.55; 95% CI 4.88-6.29), but not for IR who had not worked in shipyards (SMR 1.15; 95% CI 0.53-2.19). Likewise, deaths from asbestosis (n = 189) were also increased for shipyard and NPP workers (SMR = 18.1 and 9.2, respectively), but not among workers who never worked at a shipyard or NPP (SMR = 0.70; n = 1). Radiation dose to the lung was not associated with a statistically meaningful dose-response trend for mesothelioma in the combined cohorts (HR at 100 mGy = 1.10; 95% CI 0.96-1.27; p = .18), nor was mesothelioma risk associated with radiation exposure among IR who had not worked in a shipyard and assumed minimally exposed to asbestos. Conclusions: An elevated rate of death from mesothelioma was observed in two radiation-exposed occupational groups with potential for asbestos exposure. The increased risk of death from asbestosis, combined with little evidence of a rising trend in mesothelioma mortality with increasing radiation exposure, suggests that the mesothelioma (and asbestosis) excess in these workers was due to asbestos exposure in shipyards and power plants and not to occupational low-dose radiation.

Fibulin-3 as biomarker of malignant mesothelioma

Many malignant diseases are associated with past asbestos exposure; the most lethal and strictly related to previous fiber exposure being malignant mesothelioma (MM). Effective preventive protocols may include sensitive and specific biomarkers. The role of Fb-3 has been recently investigated for MM early detection, but its role is still under debate. After an independent search for scientific literature, nine studies were included for a systematic review. Human Fb-3 levels seem to be able to separate healthy people with previous exposure to asbestiform fibers from MM patients. Fb-3 blood levels can distinguish MM effusions from other malignant and benign effusions. Furthers investigations on more significant groups of patients are desirable to validate and assess the validity of combining Fb-3 with other biomarkers.

Breath Analysis: A Systematic Review of Volatile Organic Compounds (VOCs) in Diagnostic and Therapeutic Management of Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare neoplasm related to asbestos exposure and with high mortality rate. The management of patients with MPM is complex and controversial, particularly with regard to early diagnosis. In the last few years, breath analysis has been greatly implemented with this aim. In this review the strengths of breath analysis and preliminary results in searching breath biomarkers of MPM are highlighted and discussed, respectively. Through a systematic electronic literature search, collecting papers published from 2000 until December 2018, fifteen relevant scientific papers were selected. All papers considered were prospective, comparative, observational case-control studies although every single one pilot and based on a relatively small number of samples. The identification of diagnostic VOCs pattern, through breath sample characterization and the statistical data treatment, allows to obtain a strategic information for clinical diagnostics. To date the collected data provide just preliminary information and, despite the promising results and diagnostic accuracy, conclusions cannot be generalized due to the limited number of individuals included in each cohort study. Furthermore none of studies was externally validated, although validation process is a necessary step towards clinical implementation. Breathomics-based biomarker approach should be further explored to confirm and validate preliminary findings and to evaluate its potential role in monitoring the therapeutic response.

Biomarkers for malignant pleural mesothelioma: a meta-analysis

Malignant pleural mesothelioma (MPM) is a rare but aggressive cancer, and early detection is associated with better survival. Mesothelin, fibulin-3 and osteopontin have been suggested as screening biomarkers. The study conducted a meta-analysis of the mean differences of mesothelin, osteopontin and fibulin-3 in blood and pleural samples. PubMed searches were conducted for studies that measured levels of mesothelin, osteopontin and fibulin-3 in participants with MPM compared with malignancy, benign lung disease or healthy participants. Thirty-two studies with mesothelin levels, 12 studies with osteopontin levels and 9 studies with fibulin-3 levels were included in the meta-analysis. Statistically significant mean differences were seen between MPM patients and all other comparison groups for mesothelin blood and pleural levels. Statistically significant differences in blood osteopontin levels were seen between participants with benign lung disease and healthy participants compared with participants with MPM, but not when comparing participants with cancer with MPM participants. There were not enough studies that reported osteopontin levels in pleural fluid to complete a meta-analysis. Statistically significant differences were seen in both blood and pleural levels of fibulin-3 in MPM patients compared with all other groups. On the basis of these results, mesothelin and fibulin-3 levels appear to be significantly lower in all control groups compared with those with MPM, making them good candidates for screening biomarkers. Osteopontin may be a useful biomarker for screening healthy individuals or those with benign lung disease but would not be useful for screening patients with malignancies.

BAP1 in solid tumors

One of the most attractive cancer-related genes under investigation is BAP1. Reasons of this growing interest are related to the wide spectrum of pathways directly or indirectly modulated by this gene and shared by several solid tumors. Programmed cell-death, cell metabolisms, immune cells development, ferroptosis and defects in DNA damage response are only some of the multitude of processes depending on BAP1. Loss of this gene seems to occur in different times of tumor history. Moreover, times of BAP1 loss strongly diverge among primary tumors suggesting the presence of several and different triggering factors. Regardless of when it happens, BAP1 loss usually results in prognosis worsening and in the acquisition of more aggressive clinical features by cancer cells.

Peritoneal mesothelioma mortality in Italy: Spatial analysis and search for asbestos exposure sources

BACKGROUND

This study is part of a national plan of epidemiological surveillance of malignant mesothelioma (MM) mortality in Italy. The paper shows the results of malignant peritoneal mesothelioma (MPeM) mortality study in Italian Regions and municipalities.

METHODS

National Bureau of Statistics data for MPeM municipal mortality (ICD-10, Code C45.1) were analyzed in the time-window 2003-2014: mortality standardized rates (reference Italian population, census 2011), temporal trends of the annual national rates, Standardized Mortality Ratios and a municipal clustering analysis were performed.

RESULTS

747 deaths for MPeM were recorded (0.10/100,000): 464 in men (0.14/100,000) and in 283 women (0.07/100,000). No significant MPeM mortality temporal trend was found. Seventeen municipalities showed excesses of mortality for MPeM in at least one gender and/or overall population. Four clusters in male population, and one in women were identified.

CONCLUSIONS

The study identifies some areas where remediation activities and/or health care actions may be warranted.

Risk of mesothelioma after cessation of asbestos exposure: a systematic review and meta-regression

PURPOSE

A 'risk reversal' has been observed for several human carcinogens following cessation of exposure, but it is unclear whether it also exists for asbestos-related mesothelioma.

METHODS

We conducted a systematic review of the literature and identified nine studies that reported information on risk of mesothelioma after cessation of asbestos exposure, and performed a meta-regression based on random effects models. As comparison we analyzed results on lung cancer risk from four of these studies.

RESULTS

A total of six risk estimates from five studies were included in the meta-analysis. The summary relative risk (RR) of mesothelioma for 10-year interval since cessation of exposure was 1.02 [95% confidence interval (CI) 0.87-1.19; p-heterogeneity 0.01]. The corresponding RR of lung cancer was 0.91 (95% CI 0.84-0.98).

CONCLUSIONS

This analysis provides evidence that the risk of mesothelioma does not decrease after cessation of asbestos exposure, while lung cancer risk does.