The Global Health Dimensions of Asbestos and Asbestos-Related Diseases

Cause specific mortality in an Italian pool of asbestos workers cohorts

BACKGROUND

Asbestos is a known human carcinogen and is causally associated with malignant mesothelioma, lung, larynx and ovarian cancers.

METHODS

Cancer risk was studied among a pool of formerly asbestos-exposed workers in Italy. Fifty-two Italian asbestos cohorts (asbestos-cement, rolling-stock, shipbuilding, and other) were pooled and their mortality follow-up was updated to 2018. Standardized mortality ratios (SMRs) were computed for major causes of death considering duration of exposure and time since first exposure (TSFE), using reference rates by region, age and calendar period.

RESULTS

The study included 63,502 subjects (57,156 men and 6346 women): 40% who were alive, 58% who died (cause known for 92%), and 2% lost to follow-up. Mortality was increased for all causes (SMR: men = 1.04, 95% confidence interval [CI] 1.03-1.05; women = 1.15, 95% CI 1.11-1.18), all malignancies (SMR: men = 1.21, 95% CI 1.18-1.23; women = 1.29, 95% CI 1.22-1.37), pleural and peritoneal malignancies (men: SMR = 10.46, 95% CI 9.86-11.09 and 4.29, 95% CI 3.66-5.00; women: SMR = 27.13, 95% CI 23.29-31.42 and 7.51, 95% CI 5.52-9.98), lung (SMR: men = 1.28, 95% CI 1.24-1.32; women = 1.26, 95% CI 1.02-1.53), and ovarian cancer (SMR = 1.42, 95% CI 1.08-1.84). Pleural cancer mortality increased during the first 40 years of TSFE (latency), reaching a plateau thereafter.

CONCLUSIONS

Analyses by time-dependent variables showed that the risk for pleural neoplasms increased with latency and no longer increases at long TSFE, consistent with with asbestos clearance from the lungs. Peritoneal neoplasm risk increased over all observation time.

Global, regional, and national burden of asbestosis from 1990 to 2019 and the implications for prevention and control

BACKGROUND

Asbestosis is a common pneumoconiosis caused by long-term asbestos exposure. Analysis of the burden of asbestosis would help in creating informed public health strategies.

METHODS

Data on asbestosis were analyzed using the Global Burden of Disease study 2019. The estimated annual percentage change (EAPC) was calculated to demonstrate temporal trends in the age-standardized rate (ASR) of asbestosis from 1990 to 2019.

RESULTS

Globally, 36,339 incident cases of asbestosis, led to 3572 deaths and 71,225 disability adjusted life years (DALYs) in 2019. During 1990-2019, the overall ASRs of incidence and DALYs declined by an annual average of 0.29 % and 0.27 %, with the respective EAPCs being -0.29 (95 % confidence interval [CI]: -0.43, -0.14) and -0.27 (95%CI: -0.53, -0.01). The ASRs of mortality increased with EAPC of 0.65 (95%CI: 0.34, 0.96). Trends in incidence and prevalence rose in females, but declined in males. The asbestosis burden was heterogeneous across regions and countries. The heaviest burden of asbestosis was observed in the United States, India, and China. Trends in ASRs of asbestosis varied across countries/territories. Pronounced increasing trends in incidence and prevalence occurred in Georgia, Iran, and Croatia.

CONCLUSIONS

Decreasing incident trend of asbestosis was observed globally over the past three decades. However, the ongoing asbestosis burden highlighted that asbestosis remained a challenge to public health, and cost-effective measures were required to reduce the asbestosis burden.

The Immunological Landscape of M1 and M2 Macrophages and Their Spatial Distribution in Patients with Malignant Pleural Mesothelioma

BACKGROUND

Several tumor-associated macrophages (TAMs) have shown promise as prognosticators in cancer. Our aim was to validate the importance of TAMs in malignant pleural mesothelioma (MPM) using a two-stage design.

METHODS

We explored The Cancer Genome Atlas (TCGA-MESO) to select immune-relevant macrophage genes in MPM, including M1/M2 markers, as a discovery cohort. This computational cohort was used to create a multiplex immunofluorescence panel. Moreover, a cohort of 68 samples of MPM in paraffin blocks was used to validate the macrophage phenotypes and the co-localization and spatial distribution of these immune cells within the TME and the stromal or tumor compartments.

RESULTS

The discovery cohort revealed six immune-relevant macrophage genes (CD68, CD86, CD163, CD206, ARG1, CD274), and complementary genes were differentially expressed by M1 and M2 phenotypes with distinct roles in the tumor microenvironment and were associated with the prognosis. In addition, immune-suppressed MPMs with increased enrichment of CD68, CD86, and CD163 genes and high densities of M2 macrophages expressing CD163 and CD206 proteins were associated with worse overall survival (OS). Interestingly, below-median distances from malignant cells to specific M2a and M2c macrophages were associated with worse OS, suggesting an M2 macrophage-driven suppressive component in these tumors.

CONCLUSIONS

The interactions between TAMs in situ and, particularly, CD206+ macrophages are highly relevant to patient outcomes. High-resolution technology is important for identifying the roles of macrophage populations in tissue specimens and identifying potential therapeutic candidates in MPM.

BAP1 Loss Is Associated with Higher ASS1 Expression in Epithelioid Mesothelioma: Implications for Therapeutic Stratification

The nuclear deubiquitylase BRCA1-associated protein 1 (BAP1) is frequently inactivated in malignant pleural mesothelioma (MPM) and germline BAP1 mutation predisposes to cancers including MPM. To explore the influence on cell physiology and drug sensitivity, we sequentially edited a predisposition mutation (w-) and a promoter trap (KO) into human mesothelial cells. BAP1w-/KO MeT5A cells express less BAP1 protein and phenocopy key aspects of BAP1 loss in MPM. Stable isotope labeling with amino acids in cell culture-mass spectrometry revealed evidence of metabolic adaptation, with concomitant alteration of cellular metabolites. In MeT5A, BAP1 deficiency reduces glycolytic enzyme levels but increases enzymes involved in the tricarboxylic acid cycle and anaplerotic pathways. Notably both argininosuccinate synthase 1 (ASS1), essential for cellular synthesis of arginine, and its substrate aspartate, are elevated in BAP1w-/KO MeT5A cells. Likewise, ASS1 expression is higher in BAP1-altered MPM cell lines, and inversely correlates with BAP1 in The Cancer Genome Atlas MESO dataset. Elevated ASS1 is also evident by IHC staining in epithelioid MPM lacking nuclear BAP1 expression, with improved survival among patients with BAP1-negative/ASS1-expressing tumors. Alterations in arginine metabolism may sensitize cells to metabolic drugs and we find that BAP1-negative/ASS1-expressing MPM cell lines are more sensitive to ASS1 inhibition, although not to inhibition of purine synthesis by mizoribine. Importantly, BAP1w-/KO MeT5A become desensitized to arginine deprivation by pegylated arginine deiminase (ADI-PEG20), phenocopying BAP1-negative/ASS1-expressing MPM cell lines.

IMPLICATIONS

Our data reveal an interrelationship between BAP1 and arginine metabolism, providing a potential means of identifying patients with epithelioid MPM likely to benefit from ADI-PEG20.

Hospital Occupational Health Service Network and Reporting Systems in Taiwan From 2008 to 2021

OBJECTIVE

To evaluate the provision of occupational health services at hospitals following the establishment of the Network of Occupational Disease and Injury Service in 2007.

METHODS

A review of occupational health services during 2008 to 2021 was conducted. The medical practice-based reporting system was compared with the database of compensated occupational diseases (ODs) from Taiwan's Labor Insurance.

RESULTS

First-time outpatient visits for occupational evaluation and total visits to Network of Occupational Disease and Injury Service health care institutions increased from 1777 and 9435 to 12,092 and 23,210, respectively. Reported ODs increased from 1626 to 2043 with a peak of 2791. Up to 1380 workers evaluated for work resumption in 2021. Similar to the increasing trend in reported ODs, the number of compensated ODs increased over years.

CONCLUSION

The health service needs of Taiwanese workers from OD evaluation to vocational rehabilitation are increasing.

The Chick Embryo Xenograft Model for Malignant Pleural Mesothelioma: A Cost and Time Efficient 3Rs Model for Drug Target Evaluation

Malignant pleural mesothelioma (MPM) has limited treatment options and poor prognosis. Frequent inactivation of the tumour suppressors BAP1, NF2 and P16 may differentially sensitise tumours to treatments. We have established chick chorioallantoic membrane (CAM) xenograft models of low-passage MPM cell lines and protocols for evaluating drug responses. Ten cell lines, representing the spectrum of histological subtypes and tumour suppressor status, were dual labelled for fluorescence/bioluminescence imaging and implanted on the CAM at E7. Bioluminescence was used to assess viability of primary tumours, which were excised at E14 for immunohistological staining or real-time PCR. All MPM cell lines engrafted efficiently forming vascularised nodules, however their size, morphology and interaction with chick cells varied. MPM phenotypes including local invasion, fibroblast recruitment, tumour angiogenesis and vascular remodelling were evident. Bioluminescence imaging could be used to reliably estimate tumour burden pre- and post-treatment, correlating with tumour weight and Ki-67 staining. In conclusion, MPM-CAM models recapitulate important features of the disease and are suitable to assess drug targets using a broad range of MPM cell lines that allow histological or genetic stratification. They are amenable to multi-modal imaging, potentially offering a time and cost-efficient, 3Rs-compliant alternative to rodent xenograft models to prioritise candidate compounds from in vitro studies.

Quantitative Assessment of Asbestos Fibers in Normal and Pathological Peritoneal Tissue-A Scoping Review

Peritoneal tissue is the second most affected site by malignant mesothelioma linked to asbestos exposure. This scoping review aims to summarize the findings of the studies in which asbestos fibers in the peritoneum were quantified by electron microscopy, occasionally associated with spectroscopy, both in neoplastic and non-neoplastic tissue. The 9 studies selected comprised 62 cases, out of whom 100 samples were analyzed. Asbestos fibers were detected in 58 samples (58%). In addition, 28 cases had diagnosis of peritoneal mesothelioma. For 32 cases, a lung tumor sample was available: 28/32 samples analyzed presented asbestos fibers; 18/32 reported amphiboles with a range from not detected to 14.2 million fibers per gram of dry tissue (mfgdt); 18/32 reported chrysotile, with a range of 0 to 90 mfgdt. The studies were heterogeneous for type of samples, analytical technology, and circumstances of exposure to asbestos. To evaluate asbestos fibers in the peritoneum and to better understand the association between asbestos exposure and malignant peritoneal mesothelioma, it is desirable that the search for asbestos fibers becomes a routine process every time peritoneal tissue is accessible.

Ecological Transition in the Field of Brake Pad Manufacturing: An Overview of the Potential Green Constituents

Nowadays, the drive for green products has undergone a rapid increase following the global ecoawareness and the severe regulations aimed at preventing the environment from further damage. The use of ecosafe constituents in materials for harsh applications, such as brake pad systems, can be a possible solution for reducing health hazards arising from particle release during braking. Based on this, the present study provides a bibliographic review of green alternative constituents for friction material formulation, focusing the attention on their influence on the tribological properties of the final composites. The traditional materials still used in commercial brake pads are shortly described, with the aim to provide an overview of the current situation. In the final part of the review, following the trend of circular economy, works dealing with the use of waste as an ingredient of friction materials are also reported. The whole literature screening points out that much work is still required to obtain completely green friction materials. Indeed, few works dealing with the phenolic resin replacement, proposing inorganic ecosafe materials such as geopolymers, are present. On the contrary, the use of natural fibers is widely investigated: palm kernel, flax, agave and aloe can be identified as promising constituents based on the literature results and the generated patents.

Asbestosis diagnosis algorithm combining the lung segmentation method and deep learning model in computed tomography image

BACKGROUND

Early detection of asbestosis is important; hence, quick and accurate diagnostic tools are essential. This study aimed to develop an algorithm that combines lung segmentation and deep learning models that can be utilized as a clinical decision support system (CDSS) for diagnosing patients with asbestosis in segmented computed tomography (CT) images.

METHODS

We accurately segmented the lungs in CT images of patients examined at Seoul St. Mary's Hospital using a threshold-based method. Lungs with asbestosis and normal lungs were classified by applying the segmented image to the long-term recurrent convolutional network deep learning model. Performance was evaluated using the area under the receiver operating characteristic curve (AUROC) and F1 score from the test data.

RESULTS

The algorithm developed using the DenseNet201pre-trained model showed excellent performance, with a sensitivity of 0.962, specificity of 0.975, accuracy of 0.970, AUROC of 0.968, and F1 score of 0.961.

CONCLUSIONS

We developed an algorithm with significantly better diagnostic accuracy than a radiologist (0.970 vs. 0.73-0.79). Our developed algorithm is expected to be an excellent support tool if used as a CDSS to diagnose asbestosis using CT images.

Serum Calretinin as a Biomarker in Malignant Mesothelioma

The early diagnosis of malignant mesothelioma (MM) could improve the prognosis of MM patients. To confirm an MM diagnosis, an immunohistochemical analysis of several tumor tissue markers, including calretinin, is currently required. Our aim is to evaluate serum calretinin as a potential biomarker in asbestos-related diseases, especially in MM. Our study includes 549 subjects: 164 MM patients, 117 subjects with asbestosis, 195 subjects with pleural plaques and 73 occupationally asbestos-exposed subjects without asbestos-related diseases. The serum calretinin concentration was determined with a commercially available enzyme immunoassay. Data on the soluble mesothelin-related peptides (SMRP) concentration are available from previous studies. MM patients had a significantly higher calretinin concentration than subjects without disease, subjects with pleural plaques or subjects with asbestosis (all p < 0.001). The histological type was significantly associated with serum calretinin: patients with sarcomatoid MM had lower calretinin than patients with the epithelioid type (p = 0.001). In a ROC curve analysis, the area under the curve for calretinin concentration predicting MM was 0.826 (95% CI = 0.782-0.869; p < 0.001). At the cutoff value of 0.32 ng/mL, sensitivity was 0.683, while specificity was 0.886. The combination of calretinin and SMRP had the highest predictive value. Calretinin is a useful biomarker that can distinguish MM from other asbestos-related diseases and could, therefore, contribute to an earlier non-invasive diagnosis of MM.

Burden of Mortality from Asbestos-Related Diseases in Italy

Asbestos is one of the major worldwide occupational carcinogens. The global burden of asbestos-related diseases (ARDs) was estimated around 231,000 cases/year. Italy was one of the main European asbestos producers until the 1992 ban. The WHO recommended national programs, including epidemiological surveillance, to eliminate ARDs. The present paper shows the estimate of the burden of mortality from ARDs in Italy, established for the first time. National standardized rates of mortality from mesothelioma and asbestosis and their temporal trends, based on the National Institute of Statistics database, were computed. Deaths from lung cancer attributable to asbestos exposure were estimated using population-based case-control studies. Asbestos-related lung and ovarian cancer deaths attributable to occupational exposure were estimated, considering the Italian occupational cohort studies. In the 2010-2016 period, 4400 deaths/year attributable to asbestos were estimated: 1515 from mesothelioma, 58 from asbestosis, 2830 from lung and 16 from ovarian cancers. The estimates based on occupational cohorts showed that each year 271 deaths from mesothelioma, 302 from lung cancer and 16 from ovarian cancer were attributable to occupational asbestos exposure in industrial sectors with high asbestos levels. The important health impact of asbestos in Italy, 10-25 years after the ban, was highlighted. These results suggest the need for appropriate interventions in terms of prevention, health care and social security at the local level and could contribute to the global estimate of ARDs.

Assessment of Global Trends in the Diagnosis of Mesothelioma From 1990 to 2017

IMPORTANCE

It is difficult for policy makers and clinicians to formulate targeted management strategies for mesothelioma because data on current epidemiological patterns worldwide are lacking.

OBJECTIVE

To evaluate the mesothelioma burden across the world and describe its epidemiological distribution over time and by sociodemographic index (SDI) level, geographic location, sex, and age.

DESIGN, SETTING, AND PARTICIPANTS

Annual case data and age-standardized rates of incidence, death, and disability-adjusted life-years associated with mesothelioma among different age groups were obtained from the Global Burden of Disease 2017 database. The estimated annual percentage changes in age-standardized rates were calculated to evaluate temporal trends in incidence and mortality. The study population comprised individuals from 21 regions in 195 countries and territories who were diagnosed with mesothelioma between 1990 and 2017. Data were collected from May 23, 2019, to January 18, 2020.

MAIN OUTCOMES AND MEASURES

Primary outcomes were incident cases, deaths, and their age-standardized rates and estimated annual percentage changes. Secondary outcomes were disability-adjusted life-years and relative temporal trends.

RESULTS

Overall, 34 615 new cases (95% uncertainty interval [UI], 33 530-35 697 cases) of mesothelioma and 29 909 deaths (95% UI, 29 134-30 613 deaths) associated with mesothelioma were identified in 2017, and more than 70% of these cases and deaths were among male individuals. In 1990, the number of incident cases was 21 224 (95% UI, 17 503-25 450), and the number of deaths associated with mesothelioma was 17 406 (95% UI, 14 495-20 660). These numbers increased worldwide from 1990 to 2017, with more than 50% of cases recorded in regions with high SDI levels, whereas the age-standardized incidence rate (from 0.52 [95% UI, 0.43-0.62] in 1990 to 0.44 [95% UI, 0.42-0.45] in 2017) and the age-standardized death rate (from 0.44 [95% UI, 0.37-0.52] in 1990 to 0.38 [95% UI, 0.37-0.39] in 2017) decreased, with estimated annual percentage changes of -0.61 (95% CI, -0.67 to -0.54) for age-standardized incidence rate and -0.44 (95% CI, -0.52 to -0.37) for age-standardized death rate. The proportion of incident cases among those 70 years or older continued to increase (from 36.49% in 1990 to 44.67% in 2017), but the proportion of patients younger than 50 years decreased (from 16.74% in 1990 to 13.75% in 2017) over time. In addition, mesothelioma incident cases and age-standardized incidence rates began to decrease after 20 years of a complete ban on asbestos use. For example, in Italy, a complete ban on asbestos went into effect in 1992; incident cases increased from 1409 individuals (95% UI, 1013-1733 individuals) in 1990, peaked in 2015 after 23 years of the asbestos ban, then decreased from 1820 individuals (95% UI, 1699-1981 individuals) in 2015 to 1746 individuals (95% UI, 1555-1955 individuals) in 2017.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that incident cases of mesothelioma and deaths associated with mesothelioma continuously increased worldwide, especially in resource-limited regions with low SDI levels. Based on these findings, global governments and medical institutions may consider formulating optimal policies and strategies for the targeted prevention and management of mesothelioma.

Development of the "National Asbestos Profile" to Eliminate Asbestos-Related Diseases in 195 Countries

Worldwide, 230,000+ people die annually from asbestos-related diseases (ARDs). The World Health Organization (WHO) recommends that countries develop a National Asbestos Profile (NAP) to eliminate ARDs. For 195 countries, we assessed the global status of NAPs (A: bona fide NAP, B: proxy NAP, C: relevant published information, D: no relevant information) by national income (HI: high, UMI: upper-middle, LMI: lower-middle, LI: low), asbestos bans (banned, no-ban) and public data availability. Fourteen (7% of 195) countries were category A (having a bona fide NAP), while 98, 51 and 32 countries were categories B, C and D, respectively. Of the 14 category-A countries, 8, 3 and 3 were LMI, UMI and HI, respectively. Development of a bona fide NAP showed no gradient by national income. The proportions of countries having a bona fide NAP were similar between asbestos-banned and no-ban countries. Public databases useful for developing NAPs contained data for most countries. Irrespective of the status of national income or asbestos ban, most countries have not developed a NAP despite having the potential. The global status of NAP is suboptimal. Country-level data on asbestos and ARDs in public databases can be better utilized to develop NAPs for globally eliminating ARDs.

Role of microRNAs in Lung Carcinogenesis Induced by Asbestos

MicroRNAs are a class of small noncoding endogenous RNAs 19–25 nucleotides long, which play an important role in the post-transcriptional regulation of gene expression by targeting mRNA targets with subsequent repression of translation. MicroRNAs are involved in the pathogenesis of numerous diseases, including cancer. Lung cancer is the leading cause of cancer death in the world. Lung cancer is usually associated with tobacco smoking. However, about 25% of lung cancer cases occur in people who have never smoked. According to the International Agency for Research on Cancer, asbestos has been classified as one of the cancerogenic factors for lung cancer. The mechanism of malignant transformation under the influence of asbestos is associated with the genotoxic effect of reactive oxygen species, which initiate the processes of DNA damage in the cell. However, epigenetic mechanisms such as changes in the microRNA expression profile may also be implicated in the pathogenesis of asbestos-induced lung cancer. Numerous studies have shown that microRNAs can serve as a biomarker of the effects of various adverse environmental factors on the human body. This review examines the role of microRNAs, the expression profile of which changes upon exposure to asbestos, in key processes of carcinogenesis, such as proliferation, cell survival, metastasis, neo-angiogenesis, and immune response avoidance.

Pleural mesothelioma: When echo-endoscopy (EUS-B-FNA) leads to diagnosis in a minimally invasive way

Malignant pleural mesothelioma (MPM) is an asbestos‐related and locally invasive tumor with poor prognosis. The acquisition of histological material is mandatory in order to establish a diagnosis. In this situation, the sampling of tissue is generally performed via a thoracoscopic pleural biopsy, either medically or surgically. The use of endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) or transesophageal fine needle aspiration with an EBUS scope (EUS‐B‐FNA) of pleural lesions have only rarely been reported due to the theoretical limitations of tissue acquisition in such cases. We herein report a rare case of MPM successfully diagnosed via EUS‐B‐FNA in a 49‐year‐old woman with an unusual presentation characterized by solid thickening in the right mediastinal pleura.

Burden of Mesothelioma Deaths by National Income Category: Current Status and Future Implications

Background: This study compares estimates of the global-level mesothelioma burden with a focus on how existing national mortality data were utilized and further assesses the interrelationship of country-level mesothelioma burden and asbestos use with national income status. Methods: Country-level mesothelioma deaths in the WHO Mortality Database as of December 2019 were analyzed by national income category of countries in terms of data availability and reliability. Numbers of mesothelioma deaths from the study of Odgerel et al. were reanalyzed to assess country-level mesothelioma death burdens by national income status. Results: Among 80 high-income countries, 54 (68%) reported mesothelioma to the WHO and 26 (32%) did not, and among 60 upper middle-income countries, the respective numbers (proportions) were 39 (65%) countries and 21 (35%) countries, respectively. In contrast, among 78 low- and lower middle-income countries, only 11 (14%) reported mesothelioma deaths while 67 (86%) did not. Of the mesothelioma deaths, 29,854 (78%) were attributed to high- and upper middle-income countries, and 8534 (22%) were attributed to low- and lower middle- income countries. Conclusions: The global mesothelioma burden, based on reported numbers, is currently shouldered predominantly by high-income countries; however, mesothelioma burdens will likely manifest soon in upper middle-income and eventually in low and lower middle-income countries.

Asbestos and Intrahepatic Cholangiocarcinoma

The link between asbestos exposure and the onset of thoracic malignancies is well established. However epidemiological studies have provided evidences that asbestos may be also involved in the development of gastrointestinal tumors, including intrahepatic cholangiocarcinoma (ICC). In line with this observation, asbestos fibers have been detected in the liver of patients with ICC. Although the exact mechanism still remains unknown, the presence of asbestos fibers in the liver could be explained in the light of their translocation pathway following ingestion/inhalation. In the liver, thin and long asbestos fibers could remain trapped in the smaller bile ducts, particularly in the stem cell niche of the canals of Hering, and exerting their carcinogenic effect for a long time, thus inducing hepatic stem/progenitor cells (HpSCs) malignant transformation. In this scenario, chronic liver damage induced by asbestos fibers over the years could be seen as a classic model of stem cell-derived carcinogenesis, where HpSC malignant transformation represents the first step of this process. This phenomenon could explain the recent epidemiological findings, where asbestos exposure seems mainly involved in ICC, rather than extrahepatic cholangiocarcinoma, development.

The Current Understanding Of Asbestos-Induced Epigenetic Changes Associated With Lung Cancer

Asbestos is a naturally occurring mineral consisting of extremely fine fibres that can become trapped in the lungs after inhalation. Occupational and environmental exposures to asbestos are linked to development of lung cancer and malignant mesothelioma, a cancer of the lining surrounding the lung. This review discusses the factors that are making asbestos-induced lung cancer a continuing problem, including the extensive historic use of asbestos and decades long latency between exposure and disease development. Genomic mutations of DNA nucleotides and gene rearrangements driving lung cancer are well-studied, with biomarkers and targeted therapies already in clinical use for some of these mutations. The genes involved in these mutation biomarkers and targeted therapies are also involved in epigenetic mechanisms and are discussed in this review as it is hoped that identification of epigenetic aberrations in these genes will enable the same gene biomarkers and targeted therapies to be used. Currently, understanding of how asbestos fibres trapped in the lungs leads to epigenetic changes and lung cancer is incomplete. It has been shown that oxidoreduction reactions on fibre surfaces generate reactive oxygen species (ROS) which in turn damage DNA, leading to genetic and epigenetic alterations that reduce the activity of tumour suppressor genes. Epigenetic DNA methylation changes associated with lung cancer are summarised in this review, and some of these changes will be due to asbestos exposure. So far, little research has been carried out to separate the asbestos driven epigenetic changes from those due to non-asbestos causes of lung cancer. Asbestos-associated lung cancers exhibit less methylation variability than lung cancers in general, and in a large proportion of samples variability has been found to be restricted to promoter regions. Epigenetic aberrations in cancer are proving to be promising biomarkers for diagnosing cancers. It is hoped that further understanding of epigenetic changes in lung cancer can result in useful asbestos-associated lung cancer biomarkers to guide treatment. Research is ongoing into the detection of lung cancer epigenetic alterations using non-invasive samples of blood and sputum. These efforts hold the promise of non-invasive cancer diagnosis in the future. Efforts to reverse epigenetic aberrations in lung cancer by epigenetic therapies are ongoing but have not yet yielded success.

Malignant mesothelioma in Sub-Saharan Africa: A case report from Lubumbashi, DR Congo

Although asbestos has been used throughout Africa in the past decades, no reports of asbestos-related malignant mesothelioma are available from sub-Saharan Africa, except from South Africa and Zimbabwe. We present a case of a 39-year-old man who died from a histologically proven malignant mesothelioma of the peritoneum in Lubumbashi, DR Congo. No occupational exposure to asbestos could be found in his history. In view of his young age, we speculated that he had been exposed to asbestos as a child, which was highly plausible because he had grown up in one of the numerous mining estates of the region. The houses of these estates were often built with asbestos-containing materials, notably roofs made of corrugated asbestos-cement. The possibility of past domestic or environmental exposure to asbestos was substantiated by the identification of chrysotile and crocidolite fibres in samples of asbestos-cement collected from the home where the patient had lived as a child. To our knowledge, this is the first report of malignant mesothelioma from a country in the Central African region. We expect that heightened awareness and improved diagnosis will lead to the detection of more asbestos-related diseases in Africa.

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.

HMGB1 as a Potential Biomarker and Therapeutic Target for Malignant Mesothelioma

Malignant mesothelioma (MM) is a rare, aggressive, and highly lethal cancer that is substantially induced by exposure to asbestos fibers. High-mobility group box 1 (HMGB1) is an intriguing proinflammatory molecule involved in MM. In this review, we describe the possible crucial roles of HMGB1 in carcinogenic mechanisms based on in vivo and in vitro experimental evidence and outline the clinical findings of epidemiological investigations regarding the possible roles of HMGB1 as a biomarker for MM. We conclude that novel strategies targeting HMGB1 may suppress MM cells and interfere with asbestos-induced inflammation.

CD8+ cytotoxic T cell responses to dominant tumor-associated antigens are profoundly weakened by aging yet subdominant responses retain functionality and expand in response to chemotherapy

Increasing life expectancy is associated with increased cancer incidence, yet the effect of cancer and anti-cancer treatment on elderly patients and their immune systems is not well understood. Declining T cell function with aging in response to infection and vaccination is well documented, however little is known about aged T cell responses to tumor antigens during cancer progression or how these responses are modulated by standard chemotherapy. We examined T cell responses to cancer in aged mice using AE17sOVA mesothelioma in which ovalbumin (OVA) becomes a 'spy' tumor antigen containing one dominant (SIINFEKL) and two subdominant (KVVRFDKL and NAIVFKGL) epitopes. Faster progressing tumors in elderly (22-24 months, cf. 60-70 human years) relative to young (2-3 months, human 15-18 years) mice were associated with increased pro-inflammatory cytokines and worsened cancer cachexia. Pentamer staining and an in-vivo cytotoxic T lymphocyte (CTL) assay showed that whilst elderly mice generated a greater number of CD8⁺ T cells recognizing all epitopes, they exhibited a profound loss of function in their ability to lyse targets expressing the dominant, but not subdominant, epitopes compared to young mice. Chemotherapy was less effective and more toxic in elderly mice however, similar to young mice, chemotherapy expanded CTLs recognizing at least one subdominant epitope in tumors and draining lymph nodes, yet treatment efficacy still required CD8⁺ T cells. Given the significant dysfunction associated with elderly CTLs recognizing dominant epitopes, our data suggest that responses to subdominant tumor epitopes may become important when elderly hosts with cancer are treated with chemotherapy.

Upcoming epidemic of asbestos-related malignant pleural mesothelioma in Taiwan: A prediction of incidence in the next 30 years

BACKGROUND/PURPOSE

Globally, asbestos-related diseases (ARDs) keep rising over the coming decades. The epidemic of ARDs will be a burden on public health. We aimed to predict the malignant pleural mesothelioma (MPM) incidence in the next 30 years for Taiwan based on historical asbestos consumption.

METHODS

We collected annual data on local asbestos consumption during 1939-2015 and sex-specific incidence of pleural cancer as a proxy for MPM during 1979-2013. We applied Poisson log-linear models to predict future MPM numbers under the assumption that latency periods between asbestos exposure and MPM incidence were between 25 and 45 years.

RESULTS

Asbestos consumption reached a peak in the 1980s, with a total of 668 thousand metric tons during 1939-2015. The observed number of MPM incidence increased by 9- and 6-fold in males and females during 1979-2013, with a cumulative number of 907. Given a latency period of 31 years, MPM incidences were expected to peak around 2012-2016 for males and 2016-2020 for females. In 2017-2046, the predicted total number of new MPM might reach 659 cases (95% confidence interval = 579-749); and the male to female ratios ranged from 1.8 to 2.8.

CONCLUSION

The MPM epidemic in Taiwan will likely peak in 2012-2020 as a result of local asbestos consumption. Approximately 659 new MPM cases in the next 30 years warrant an urgent need to implement a total asbestos ban and put more resources on a comprehensive surveillance, diagnosis, and follow-up health care system for ARDs.

Bibliometric analysis of gaps in research on asbestos-related diseases: declining emphasis on public health over 26 years

OBJECTIVES

The global burden of asbestos-related diseases (ARDs) is significant, and most of the world's population live in countries where asbestos use continues. We examined the gaps between ARD research and suggestions of WHO and the International Labour Organization on prevention.

METHODS

From the Web of Science, we collected data on all articles published during 1991-2016 and identified a subset of ARD-related articles. We classified articles into three research areas-laboratory, clinical and public health-and examined their time trends. For all and the top 11 countries publishing ARD-related articles, we calculated the proportions of all ARD-related articles that were in each of the three areas, the average rates of ARD-related articles over all articles, and the average annual per cent changes of rates.

RESULTS

ARD-related articles (n=14 284) accounted for 1.3‰ of all articles in 1991, but this had declined to 0.8‰ by 2016. Among the three research areas, the clinical area accounted for the largest proportion (65.0%), followed by laboratory (26.5%) and public health (24.9%). The public health area declined faster than the other areas, at -5.7% per year. Discrepancies were also observed among the top 11 countries regarding emphasis on public health research, with Finland and Italy having higher, and China and the Netherlands lower, emphases.

CONCLUSIONS

There is declining emphasis on the public health area in the ARD-related literature. Under the ongoing global situation of ARD, primary prevention will remain key for some time, warranting efforts to rectify the current trend in ARD-related research.

Dysregulated Expression of the MicroRNA miR-137 and Its Target YBX1 Contribute to the Invasive Characteristics of Malignant Pleural Mesothelioma

INTRODUCTION

Malignant pleural mesothelioma (MPM) is an aggressive malignancy linked to asbestos exposure. On a genomic level, MPM is characterized by frequent chromosomal deletions of tumor suppressors, including microRNAs. MiR-137 plays a tumor suppressor role in other cancers, so the aim of this study was to characterize it and its target Y-box binding protein 1 (YBX1) in MPM.

METHODS

Expression, methylation, and copy number status of miR-137 and its host gene MIR137HG were assessed by polymerase chain reaction. Luciferase reporter assays confirmed a direct interaction between miR-137 and Y-box binding protein 1 gene (YBX1). Cells were transfected with a miR-137 inhibitor, miR-137 mimic, and/or YBX1 small interfering RNA, and growth, colony formation, migration and invasion assays were conducted.

RESULTS

MiR-137 expression varied among MPM cell lines and tissue specimens, which was associated with copy number variation and promoter hypermethylation. High miR-137 expression was linked to poor patient survival. The miR-137 inhibitor did not affect target levels or growth, but interestingly, it increased miR-137 levels by means of mimic transfection suppressed growth, migration, and invasion, which was linked to direct YBX1 downregulation. YBX1 was overexpressed in MPM cell lines and inversely correlated with miR-137. RNA interference-mediated YBX1 knockdown significantly reduced cell growth, migration, and invasion.

CONCLUSIONS

MiR-137 can exhibit a tumor-suppressive function in MPM by targeting YBX1. YBX1 knockdown significantly reduces tumor growth, migration, and invasion of MPM cells. Therefore, YBX1 represents a potential target for novel MPM treatment strategies.

Capture of mesothelioma cells with 'universal' CTC-chip

Malignant mesothelioma (MM) is a highly aggressive malignant tumor, predominantly associated with job-related exposure to asbestos. Development of effective and non-invasive modalities for diagnosis is an important issue in occupational medicine. Circulating tumor cells (CTCs), which are tumor cells that are shed from primary tumors and circulate in the peripheral blood, may be detected at an earlier stage than malignant tumors, and detection of CTCs may provide a novel insight into the diagnosis of MM. In a previous study evaluating clinical utility of CTCs, detected with a widely used system 'CellSearch', the authors indicated a significant however insufficient capability in the diagnosis of MM, suggesting need for a more sensitive system. Accordingly, the authors developed a novel microfluidic system to capture CTCs (CTC-chip), and demonstrated that the CTC-chip effectively captured MM cells (ACC-MESO-4) spiked in the blood by conjugating an anti-podoplanin antibody. The results of the present study demonstrated that the CTC-chip coated with the anti-podoplanin antibody captured another MM cell (ACC-MESO-1). However, the capture efficiencies were lower than those for ACC-MESO-4. In addition, an anti-mesothelin antibody was used to capture CTCs, however the CTC-chip coated with the anti-mesothelin antibody failed to effectively capture MM cells, possibly due to low mesothelin expression. Overall, the CTC-chip may capture specific types of CTCs by conjugating any antibody against an antigen expressed on CTCs, and may be a useful system for the diagnosis of malignant tumors, including MM.

Asbestos-associated genome-wide DNA methylation changes in lung cancer

Previous studies have revealed a robust association between exposure to asbestos and human lung cancer. Accumulating evidence has highlighted the role of epigenome deregulation in the mechanism of carcinogen-induced malignancies. We examined the impact of asbestos on DNA methylation. Our genome-wide studies (using Illumina HumanMethylation450K BeadChip) of lung cancer tissue and paired normal lung from 28 asbestos-exposed or non-exposed patients, mostly smokers, revealed distinctive DNA methylation changes. We identified a number of differentially methylated regions (DMR) and differentially variable, differentially methylated CpGs (DVMC), with individual CpGs further validated by pyrosequencing in an independent series of 91 non-small cell lung cancer and paired normal lung. We discovered and validated BEND4, ZSCAN31 and GPR135 as significantly hypermethylated in lung cancer. DMRs in genes such as RARB (FDR 1.1 × 10-19 , mean change in beta [Δ] -0.09), GPR135 (FDR 1.87 × 10-8 , mean Δ -0.09) and TPO (FDR 8.58 × 10-5 , mean Δ -0.11), and DVMCs in NPTN, NRG2, GLT25D2 and TRPC3 (all with p <0.05, t-test) were significantly associated with asbestos exposure status in exposed versus non-exposed lung tumors. Hypomethylation was characteristic to DVMCs in lung cancer tissue from asbestos-exposed subjects. When DVMCs related to asbestos or smoking were analyzed, 96% of the elements were unique to either of the exposures, consistent with the concept that the methylation changes in tumors may be specific for risk factors. In conclusion, we identified novel DNA methylation changes associated with lung tumors and asbestos exposure, suggesting that changes may be present in causal pathway from asbestos exposure to lung cancer.

Asbestos Exposures, Mesothelioma Incidence and Mortality, and Awareness by General Practitioners in the Molise Region, Central Italy

OBJECTIVE

The aim of this study was to evaluate environmental asbestos sources, mesothelioma incidence and mortality, and awareness on asbestos-related diseases (ARDs) by general practitioners (GPs) in Molise Region.

METHODS

The contaminated sites in three towns were identified by census; mesothelioma incidence (2000 to 2012) and mortality (2003 to 2013) was achieved from local registries; GPs were interviewed on practiced population's exposures and ARDs diagnosis.

RESULTS

About 54.3% of visited sites were contaminated (71.2% by friable asbestos) and 38.8% was extremely damaged. Over above time-periods, 32 mesothelioma cases (62.5% males, 25% in people aged 70 to 75 years) and 27 deaths (90% males, 69 ± 10 years, 70.4% pleural mesothelioma) have been reported. A total of 122 GPs were interviewed who had diagnosed 40 mesothelioma and 28 asbestosis cases.

CONCLUSION

There is the need of remediation/removal interventions for contaminated sites and of strategies to increase GPs awareness on asbestos risks for better patients' management.

Asbestos-related diseases in mineworkers: a clinicopathological study

The accurate diagnosis of asbestos-related diseases is important because of past and current asbestos exposures. This study evaluated the reliability of clinical diagnoses of asbestos-related diseases in former mineworkers using autopsies as the reference standard.

Sensitivity, specificity, positive predictive value and negative predictive value were calculated.

The 149 cases identified had clinical examinations 0.3–7.4 years before death. More asbestos-related diseases were diagnosed at autopsy rather than clinically: 77 versus 52 for asbestosis, 27 versus 14 for mesothelioma and 22 versus 3 for lung cancer. Sensitivity and specificity values for clinical diagnoses were 50.6% and 81.9% for asbestosis, 40.7% and 97.5% for mesothelioma, and 13.6% and 100.0% for lung cancer. False-negative diagnoses of asbestosis were more likely using radiographs of acceptable (versus good) quality and in cases with pulmonary tuberculosis at autopsy.

The low sensitivity values are indicative of the high proportion of false-negative diagnoses. It is unlikely that these were the result of disease manifestation between the last clinical assessment and autopsy. Where clinical features suggest asbestos-related diseases but the chest radiograph is negative, more sophisticated imaging techniques or immunohistochemistry for asbestos-related cancers should be used. Autopsies are useful for the detection of previously undiagnosed and misdiagnosed asbestos-related diseases, and for monitoring clinical practice and delivery of compensation.

Asbestos-related diseases are difficult to diagnose; 58% diagnosed at autopsy had been missed clinicallyhttp://ow.ly/L9u230dr0bv

Serum HMGB1 as a Potential Biomarker for Patients with Asbestos-Related Diseases

High-mobility group box 1 (HMGB1) functions as a proinflammatory cytokine and is one of the most intriguing molecules in inflammatory disorders and cancers. Notably, HMGB1 is a potential therapeutic target and novel biomarker in related diseases. However, the diagnostic value of HMGB1 for benign and malignant asbestos-related diseases (ARDs) remains unclear. In this work, we detected preoperative serum HMGB1 levels in Chinese asbestos-exposed (AE) and ARDs populations and further evaluated the diagnostic value of HMGB1 in patients with certain types of ARDs, including those with pleural plaques, asbestosis, or malignant mesothelioma (MM). The experimental data presented that the serum level of HMGB1 was significantly elevated in AE and ARDs subjects. Our findings indicated that serum HMGB1 is a sensitive and specific biomarker for discriminating asbestosis- and MM-affected individuals from healthy or AE individuals. In addition, serum matrix metalloproteinases 2 and 9 are not correlated with HMGB1 in ARDs. Thus, our study provides supporting evidence for HMGB1 as a potential biomarker either for the clinical diagnosis of high-risk AE cohorts or for evaluating ARDs.