An updated review on asbestos and related diseases in China

Burden of malignant mesothelioma in China during 1990-2019 and the projections through 2029

Objective

To provide the most up-to-date data on the burden of malignant mesothelioma (MM) and the projections through 2029 in China.

Methods

Data on patients diagnosed with MM from China during 1990-2019 were obtained from the Global Burden of Disease (GBD) 2019 database, including annual cases and deaths data and age-standardized rates of incidence, mortality, and disability-adjusted life-years (DALYs) associated with MM among different age groups. Temporal trends during 1990-2019 were analyzed by the Joinpoint regression models using 95% confidence interval (CI), while the projections through 2029 were calculated by the Bayesian age-period-cohort model. Data on the production and consumption of asbestos in China were obtained from the United States Geological Survey on Mineral Commodity Summaries during 1996-2023.

Results

We observed a significant elevation in incident new cases and deaths over the last 3 decades, increasing from 1193 in 1990 to 2815 in 2019 for incident cases and from 1134 in 1990 to 2773 in 2019 for death cases. We found a roughly 6% increase in the proportion of incident cases for those aged >70 years (30% in 2019 versus 24% in 1990), while for the proportion of deaths similar elevation for those aged >70 years was found. Additionally, men had significantly higher DALYs due to MM across age groups compared with women. Asbestos consumption in China dramatically dropped since 2012 and reached the bottom in 2017 with 230 kilotons. By 2029, the projected age-standardized rate for incidence and mortality is expected to reach 1.2 per million for both.

Conclusion

We found, for the first time using GBD data on the Chinese population, that the burden of MM has been significantly increasing in China over the last three decades and will continue to increase in the upcoming decade, suggesting an urgent need for a complete ban on chrysotile asbestos in China.

The incidence of malignancies in asbestosis with chrysotile exposure: a large Chinese prospective cohort study

Background

Asbestos exposure is closely related to the occurrence and development of various malignancies. This prospective cohort study aimed to evaluate the incidence rate and potential risk factors in a cohort of asbestosis patients in China.

Methods

The incidence of malignancies was determined in patients who had been exposed to chrysotile asbestos and diagnosed with asbestosis sequentially at Beijing Chaoyang Hospital from 1 January 2007 to 31 December 2019. Cox regression analyses were used to analyze the correlations between clinical variables and asbestosis combined with malignancies.

Results

A total of 618 patients with asbestosis were identified, of whom 544 were eligible for analysis. Among them, 89 (16.36%) were diagnosed with various malignancies. The standardized incidence ratios (SIRs) of patients with asbestosis combined with malignancies were 16.61, 175, 5.23, and 8.77 for lung cancer, mesothelioma, breast cancer, and endometrial carcinoma, respectively. The risks of all malignancies and lung cancer increased with initial exposure before 17 years old, longer asbestos exposure, and smoking.

Conclusions

The SIRs of patients with asbestosis-related malignancies were significantly increased in lung cancer, mesothelioma, breast cancer, and endometrial carcinoma in a hospital-based Chinese cohort. Smoking and the duration of asbestos exposure increased the risk of lung cancer.

Mortality due to respiratory system disease and lung cancer among female workers exposed to chrysotile in Eastern China: A cross-sectional study

Female workers in the asbestos processing industry of Eastern China are at high risk of developing multiple types of cancer, and more data are urgently needed to better understand and address this issue. Death certificate data were selected from an asbestos processing city in China from 2005 to 2006. Information was investigated using the relatives of those individuals who had died as sources of information. Individuals were classified into one of three asbestos exposure levels. Standardized mortality ratio and 95% confidence interval were calculated. A total of 2,964 individual deaths were identified from 2005 to 2006; of these, 21.4% were occupationally exposed to asbestos. The main cause of death was circulatory system diseases (21.2%). The proportion of individuals with respiratory system diseases increased by age among each exposure subgroup (P_trend < 0.01). Among females, a significant trend was observed between increased asbestos exposure and mortality due to respiratory system diseases and lung cancer. Our study indicated that asbestos exposure was associated with excess mortality from lung cancer and respiratory diseases, particularly among female workers in an asbestos processing area in Eastern China.

Plasma Metabolic Profiling in Patients With Silicosis and Asbestosis

OBJECTIVES

To explore the circulating metabolites and related pathways in silicosis and asbestosis exposure to different mineral dust.

METHODS

Plasma of 30 silicosis, 30 asbestosis, and 20 healthy controls was analyzed using liquid chromatography-mass spectrometry. Metabolic networks and the relevance of the identified metabolic derangements were explored.

RESULTS

Compared with healthy controls, 37 and 39 dysregulated plasma metabolites were found in silicosis and asbestosis, respectively, of which the levels of 22 metabolites differed. Three major pathways were identified, among which arginine and proline metabolism was identified as the most closely related metabolic pathway.

CONCLUSIONS

The types and quantities of up-regulated metabolites including lipids, amino acids, and carnitines differed between silicosis and asbestosis. Pathways inducing lung fibrosis were common to mineral dust exposure, while pathways related to oxidative stress and tumorigenesis differed between silicosis and asbestosis.

Hospitalisation costs of malignant mesothelioma: results from the Italian hospital discharge registry (2001-2018)

OBJECTIVES

This paper aims to establish hospitalisation costs of mesothelioma in Italy and to evaluate hospital-related trends associated with the 1992 asbestos ban.

DESIGN

This is a retrospective population-based study of Italian hospitalisations treating pleura, peritoneum and pericardium mesothelioma in the period 2001-2018.

SETTINGS

Public and private Italian hospitals reached by the Ministry of Health (coverage close to 100%).

PARTICIPANTS

157 221 admissions with primary or contributing diagnosis of pleural, peritoneal or hearth cancer discharged from 2001 to 2018.Primary and secondary outcome measures: number, length and cost of hospitalisations with related percentages.

RESULTS

Each year, Italian hospitals treated a mesothelioma in 6025 admissions on average. Mean annual costs by site were €20 293 733, €3183 632 and €40 443 for pleura, peritoneum and pericardium, respectively. Pericardial mesothelioma showed the highest cost per admission (€6117), followed by peritoneal (€4549) and pleural cases (€3809). Percentage of hospitalisation costs attributable to mesothelioma was higher when it is located in pleura (53.4%) and pericardium (51.8%) with respect to peritoneum (41.2%). Overall annual hospitalisation cost, percentages of number and length of admissions showed an inverted U-shape, with maxima (of €25 850 276, 0.064% and 0.096%, respectively) reached in 2011-2013. Mean age at discharge and percentages of surgery and of urgent cases increased over time.

CONCLUSIONS

The highest impact of mesothelioma on the National Health System was recorded 20 years after the asbestos ban (2011-2013). Hospitals should expect soon fewer but more severe patients needing more cares. To study the disease prevalence could help assistance planning of next decade.

Role of PARP1 on DNA damage induced by mineral silicate chrysotile in bronchial epithelial and pleural mesothelial cells

To investigate whether poly (ADP ribose) polymerase-1 (PARP1) is involved in chrysotile-induced DNA damage in pleural mesothelial cells (MeT-5A) and bronchial epithelial cells (BEAS-2B), two PARP1-deficient cell lines were established. Efficiencies of RNA interference on PARP1 were detected by western blot and qPCR. Here, normal cells and PARP1-deficient cells were exposed to chrysotile, and DNA damage and DNA repair were detected by alkaline comet assay. All cells were treated with chrysotile at the indicated concentrations (5, 10, 20, and 40 μg/cm²) for 24 h and then the DNA repair capacity was observed for 12 and 24 h, respectively. The results showed that chrysotile caused DNA damage at an obvious dose-dependent manner in MeT-5A and BEAS-2B cells. In addition, MeT-5A cells had more persistent DNA damage than BEAS-2B. Compared to normal cells, the PARP1-deficient cells were more sensitive to DNA damage caused by chrysotile. In DNA repair experiments, all cell lines recovered from the damage over time. The results of relative repair percentage (RRP) of MeT-5A and BEAS-2B were higher than those of MeT-5A shPARP1 and BEAS-2B shPARP1 cells at all experimental concentrations (except 5 μg/cm²) at 12-h repair. However, RRP of BEAS-2B and BEAS-2B shPARP1 tended to be closer, and RRP of MeT-5A shPARP1 was still lower than that of MeT-5A at 24-h repair. All results suggest that PARP1 plays an important role in early repair of DNA damage in BEAS-2B and MeT-5A cells exposed to chrysotile.

Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.

Costs of asbestosis and silicosis hospitalization in Italy (2001-2018) : Costs of asbestosis and silicosis hospitalization

BACKGROUND

Asbestosis and silicosis are preventable fibrotic forms of pneumoconiosis. Decades ago, the World Health Organization began prevention campaigns for eliminating these diseases worldwide.

PURPOSE

To establish Italian hospitalization costs of asbestosis and silicosis in relation to national adopted prevention policies.

METHODS

This is a retrospective population-based study of Italian hospitalizations treating asbestosis or silicosis in the period 2001-2018. We have extracted data from the National Hospital Discharge Registry and merged with national standard charges of hospitalizations through diagnosis-related group coding. We expressed costs in 2018 euros and evaluated data time-trends by linear normal and logistic regression models.

RESULTS

During 2001-2018, hospitalization costs per year were 3,787,540 € for asbestosis and 10,103,215 € for silicosis. There were significant annual reductions in frequency (- 41 and - 266 hospitalizations per year for asbestosis and silicosis, respectively), length of stay (- 148 and - 2781 days per year for asbestosis and silicosis, respectively) and cost (- 43,881 and - 959,516 € per year for asbestosis and silicosis, respectively) of diseases. Length and cost of hospital stay per admission significantly increased over time for asbestosis (+ 0.2 days and + 100 €, respectively, per year).

CONCLUSION

Overall hospitalizations costs were higher for silicosis than asbestosis. Over time hospitals treated fewer cases with greater severity. The decreased 2001-2018 consumption of hospital resources by patients with asbestosis or silicosis is associated with the occupational health policies instituted from the 1990s to reduce exposures to asbestos and silica. Extending existing epidemiological surveillance systems to pneumoconioses would help to control the social costs of work-related diseases.

Long-term instillation to four natural representative chrysotile of China induce the inactivation of P53 and P16 and the activation of C-JUN and C-FOS in the lung tissues of Wistar rats

Chrysotile is the only type of asbestos still widely exploited, and all kinds of asbestos including chrysotile was classified as a group I carcinogen by the IARC. There is a wealth of evidence that chrysotile can cause a range of cancers, including cancer of the lung, larynx, ovary, and mesothelioma. As the second largest chrysotile producer, China is at great risk of occupational exposure. Moreover, our previous experiment and some other studies have shown that the toxicity of mineral fibre from various mining areas may be different. To explore the oncogenic potential of chrysotile from different mining areas of China, Wistar rats were administered 0.5 mL chrysotile asbestos suspension of 2.0 mg/mL (from Akesai, Gansu; Mangnai, Qinghai; XinKang, Sichuan; and Shannan, Shaanxi) dissolved in saline by intratracheal instillation once-monthly and were sacrificed at 1 mo, 6 mo, and 12 mo. Our results found that chrysotile caused lung inflammation and lung tissue damage. Moreover, prolonged exposure of chrysotile can induce inactivation of the tumor suppressor gene P53 and P16 and activation of the protooncogene C-JUN and C-FOS both in the messenger RNA and protein level. In addition, chrysotile from Shannan and XinKang has a stronger effect which may link to cancer than that from Akesai and Mangnai.

Oxidative effects of lungs in Wistar rats caused by long-term exposure to four kinds of China representative chrysotile

Chrysotile accounts for some 90% to 95% of all the asbestos used worldwide. Scientific evidences have shown that asbestos (including chrysotile) exposure is associated with increased rates of lung cancer, asbestosis, and mesothelioma. However, molecular mechanisms underlying the toxicity effects of chrysotile are not clear. This study evaluated the oxidative stress in chronic lung toxicity caused by the intratracheal instillation (IT) of four kinds China representative chrysotile once a month for 12 months in Wistar rats. These results indicated that chrysotile exposure led to an obvious increase in lung mass and slowed the growth of body mass. Inflammation and fibrosis were observed by hematoxylin-eosin (HE) staining. Exposure to chrysotile significantly increased the accumulation of reactive oxygen species (ROS) and the level of lipid peroxidation and decreased antioxidant capacity in lung tissues. Furthermore, 1-6-month chrysotile exposure activated heme oxygenase-1 (HO-1) and heat shock protein 70 (HSP70) expression, whereas 12-month exposure caused significant decreases of two-factor expression levels in XK and MN groups when compared to negative control group. Therefore, our results suggested that chronic chrysotile pulmonary injury in Wistar rats is triggered by oxidative damage. Meanwhile, the oxidative damage of MN and XK was stronger than that of SSX and AKS, and the difference of oxidative damage in four chrysotile could have been brought by its properties, morphology, chemical composition, and particle size. With all the above mentioned in view, we hope that the revealed data in the experiment could contribute to the progress of further researches on the toxicity and mechanism of chrysotile.

Chrysotile and rock wool fibers induce chromosome aberrations and DNA damage in V79 lung fibroblast cells

According to global estimates, at least 107,000 people die each year from asbestos-related lung cancer, mesothelioma, and asbestosis resulting from occupational exposure. Chrysotile accounts for approximately 90% of asbestos used worldwide. Artificial substitutes can also be cytotoxic to the same degree as chrysotile. But only a few researchers focused on their genetic effects and mutagenicity information which is useful in evaluating the carcinogenicity of chemicals. In this study, chrysotile from Mangnai, Qinghai, China, and an artificial substitute, rock wool fiber were prepared as suspensions and were tested at concentrations of 50, 100, and 200 μg/ml in V79 lung fibroblasts. Chromosome aberrations were detected by micronucleus assay after exposure for 24 h, and DNA damage were estimated by single cell gel electrophoresis after exposure for 12, 24, or 48 h. According to the results, chrysotile and rock wool fibers caused micronuclei to form in a dose-dependent manner in V79 cells; olive tail moment values increased in a dose- and time-dependent manner. When V79 cells were exposed to a concentration of 200 μg/ml, the degree of DNA damage induced by chrysotile fibers was greater than rock wool fibers. Our study suggests that both chrysotile and rock wool fibers could induce chromosome aberrations and DNA damage. These materials are worthy of further study.

Chrysotile effects on the expression of anti-oncogene P53 and P16 and oncogene C-jun and C-fos in Wistar rats' lung tissues

Chrysotile is the most widely used form of asbestos worldwide. China is the world's largest consumer and second largest producer of chrysotile. The carcinogenicity of chrysotile has been extensively documented, and accumulative evidence has shown that chrysotile is capable of causing lung cancer and other forms of cancer. However, molecular mechanisms underlying the tumorigenic effects of chrysotile remained poorly understood. To explore the carcinogenicity of chrysotile, Wistar rats were administered by intratracheal instillation (by an artificial route of administration) for 0, 0.5, 2, or 8 mg/ml of natural chrysotile (from Mangnai, Qinghai, China) dissolved in saline, repeated once a month for 6 months (a repeated high-dose exposure which may have little bearing on the effects following human exposure). The lung tissues were analyzed for viscera coefficients and histopathological alterations. Expression of P53, P16, C-JUN, and C-FOS was measured by western blotting and qRT-PCR. Our results found that chrysotile exposure leads the body weight to grow slowly and lung viscera coefficients to increase in a dose-dependent manner. General sample showed white nodules, punctiform asbestos spots, and irregular atrophy; moreover, HE staining revealed inflammatory infiltration, damage of alveolar structures, agglomerations, and pulmonary fibrosis. In addition, chrysotile can induce inactivation of the anti-oncogene P53 and P16 and activation of the proto-oncogenes C-JUN and C-FOS both in the messenger RNA and protein level. In conclusion, chrysotile induced an imbalanced expression of cancer-related genes in rats' lung tissue. These results contribute to our understanding of the carcinogenic mechanism of chrysotile.

Global trends in mortality from malignant mesothelioma: Analysis of WHO mortality database (1994-2013)

BACKGROUND AND OBJECTIVE

Little is known about the extent to which asbestos use ban has affected global trends in malignant mesothelioma. This study investigated recent global mortality trends of malignant mesothelioma.

METHODS

Data were collected from International Agency for Research on Cancer/World Health Organization mortality database to examine age-standardized, gender-specific mortality rates for malignant mesothelioma (ICD10-C45). Cross-sectional mortality rates (2009-2013) as well as trends over time (1994-2013) were also reported. Gender-specific annual percent change (APC) was calculated to examine trends over time for each country.

RESULTS

Among the 30 countries with highest mesothelioma mortality in men, there is almost 10-fold variation in mortality rates during 2009-2013 ranging from 6.25 per 100 000 for United Kingdom to 0.64 per 100 000 in Portugal; whereas, among the 30 countries with highest mesothelioma mortality in women, there is a 4-fold variation in mortality rates during 2009-2013 ranging from 1.08 per 100 000 for United Kingdom to 0.26 per 100 000 in Ireland. Mortality rates were higher in men compared to women in 32 out of 35 evaluable countries. Among males and over the last 10 years of covered years, mesothelioma mortality was significantly declining in 9 countries (United Kingdom, Sweden, France, Germany, Netherlands, Canada, United States, Australia, and New Zealand); whereas, it was significantly rising in 5 countries (Poland, Spain, China-Hong Kong, Japan, and Republic of Korea). In the remaining countries, APC was stable. Among females and over the last 10 years of covered years, mesothelioma mortality was significantly declining in 1 country only (Italy); whereas, it was significantly rising in 3 countries (Poland, Argentina, and Republic of Korea). In the remaining countries, APC was stable.

CONCLUSIONS

There is a worldwide variability in the burden and trends of mesothelioma mortality; and despite the ban on asbestos in many countries, mesothelioma still represents an important cause of mortality.

Recent Scientific Evidence Regarding Asbestos Use and Health Consequences of Asbestos Exposure

To justify the continuous use of two million tons of asbestos every year, it has been argued that a safe/controlled use can be achieved. The aim of this review was to identify recent scientific studies that present empirical evidence of: 1) health consequences resulting from past asbestos exposures and 2) current asbestos exposures resulting from asbestos use. Articles with evidence that could support or reject the safe/controlled use argument were also identified. A total of 155 articles were included in the review, and 87 % showed adverse asbestos health consequences or high asbestos exposures. Regarding the safe/controlled use, 44 articles were identified, and 82 % had evidence suggesting that the safe/controlled use is not being achieved. A large percentage of articles with evidence that support the safe/controlled use argument have a conflict of interest declared. Most of the evidence was developed in high-income countries and in countries that have already banned asbestos.

Serum concentrations of Krebs von den Lungen-6, surfactant protein D, and matrix metalloproteinase-2 as diagnostic biomarkers in patients with asbestosis and silicosis: a case-control study

BACKGROUND

Asbestosis and silicosis are progressive pneumoconioses characterized by interstitial fibrosis following exposure to asbestos or silica dust. We evaluated the potential diagnostic biomarkers for these diseases.

METHODS

The serum concentrations of Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D), and matrix metalloproteinase-2 (MMP-2), MMP-7, and MMP-9 were measured in 43 patients with asbestosis, 45 patients with silicosis, 40 dust-exposed workers (DEWs) without pneumoconiosis, and 45 healthy controls (HCs). Chest high-resolution computed tomography (HRCT) images were reviewed by experts blinded to the clinical data. According to the receiver operating characteristic (ROC) curve, the ideal level of each biomarker and its diagnostic sensitivity were obtained.

RESULTS

The serum KL-6 and MMP-2 concentrations were highest in patients with asbestosis, particularly in comparison with those in DEWs and HCs (P<0.05). The serum SP-D concentration was significantly higher in patients with asbestosis than in patients with silicosis, DEWs, and HCs (P<0.01), whereas no significant difference was noted among patients with silicosis, DEWs, and HCs. No significant difference in the serum MMP-7 or -9 concentration was found among patients with asbestosis, patients with silicosis, DEWs, or HCs. Among patients with asbestosis, the serum KL-6 concentration was significantly correlated with the lung fibrosis scores on HRCT and negatively correlated with the forced vital capacity (FVC) % predicted and diffusing capacity of the lung for carbon monoxide (DL_CO) % predicted. The serum SP-D and MMP-2 concentrations were negatively correlated with the DL_CO % predicted (all P<0.05). The order of diagnostic accuracy according to the ROC curve was KL-6, SP-D, and MMP-2 in patients with asbestosis alone and in the combination of both patients with asbestosis and those with silicosis. The combination of all three biomarkers may increase the possibility of diagnosing asbestosis (sensitivity, 93%; specificity, 57%) and both asbestosis and silicosis (sensitivity, 83%; specificity, 62%).

CONCLUSIONS

KL-6, SP-D, and MMP-2 are available biomarkers for the adjuvant diagnosis of asbestosis and silicosis. The combination of all three biomarkers may improve the diagnostic sensitivity for asbestosis and silicosis.

Plasma Fibulin-3 as a Potential Biomarker for Patients with Asbestos-Related Diseases in the Han Population

Fibulin-3 has been reported as a potential biomarker for mesothelioma. However, little is known about the diagnostic efficacies of fibulin-3 for asbestos-related diseases (ARDs) in China. This study was to investigate the utility of fibulin-3 for asbestos exposure and ARDs. A total of 430 subjects were recruited from Southeast China, including healthy individuals, asbestos-exposed (AE) individuals, and patients with pleural plaques (PP), asbestosis, and malignant pleural mesothelioma (MPM). Plasma fibulin-3 was measured using the enzyme-linked immunosorbent assay. Linear regression analyses were applied to explore the influencing factors of fibulin-3. Receiver operating characteristic curves were used to determine the cutoff values. The median fibulin-3 level of subjects in the mesothelioma group was higher than that in other groups. Subjects in the asbestosis group had higher median fibulin-3 level than those in the control group. A higher fibulin-3 level was found in the group with ≥10 years of asbestos exposure as compared with control groups. The AUCs of fibulin-3 for distinguishing MPM subjects from control, AE, PP, and asbestosis subjects were 0.92, 0.88, 0.90, and 0.81, respectively. Our study provided evidence that fibulin-3 could be a potential biomarker for the early screening of MPM, but not of other nonmalignant ARDs in Chinese populations.

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.

Computer-aided volumetric assessment of malignant pleural mesothelioma on CT using a random walk-based method

OBJECTIVE

The aim of this study is to assess the performance of a computer-aided semi-automated algorithm we have adapted for the purpose of segmenting malignant pleural mesothelioma (MPM) on CT.

METHODS

Forty-five CT scans were collected from 15 patients (M:F [Formula: see text] 10:5, mean age 62.8 years) in a multi-centre clinical drug trial. A computer-aided random walk-based algorithm was applied to segment the tumour; the results were then compared to radiologist-drawn contours and correlated with measurements made using the MPM-adapted Response Evaluation Criteria in Solid Tumour (modified RECIST).

RESULTS

A mean accuracy (Sørensen-Dice index) of 0.825 (95% CI [0.758, 0.892]) was achieved. Compared to a median measurement time of 68.1 min (range [40.2, 102.4]) for manual delineation, the median running time of our algorithm was 23.1 min (range [10.9, 37.0]). A linear correlation (Pearson's correlation coefficient: 0.6392, [Formula: see text]) was established between the changes in modified RECIST and computed tumour volume.

CONCLUSION

Volumetric tumour segmentation offers a potential solution to the challenges in quantifying MPM. Computer-assisted methods such as the one presented in this study facilitate this in an accurate and time-efficient manner and provide additional morphological information about the tumour's evolution over time.

Improving the Accuracy of Mesothelioma Diagnosis in China

INTRODUCTION

In the Western world, malignant mesothelioma (MM) is most prevalent in the pleura of older males who have been professionally exposed to asbestos. Information about MM from rapidly industrializing countries such as China is minimal. There is concern that a proportion of MM diagnoses in China may be incorrect because most Chinese physicians do not have experience diagnosing this rare cancer. We recently reported an unusually high incidence of peritoneal MM among eastern Chinese female patients. Here, we review the accuracy of MM diagnoses in China and provide suggestions to improve the accuracy of diagnosis.

METHODS

We reviewed 92 pathological diagnosis of MM in 2002-2015 from two reference centers in the province of Zhejiang in eastern China. We performed a large set of immunohistochemistry analyses to increase the reliability of the diagnosis.

RESULTS

We confirmed the MM diagnosis in 12 of 34 of the pleural tumors (35.3%), in 38 of 56 of the peritoneal tumors (67.9%), and in two of two of the MMs of the tunica vaginalis (100%). MMs were characterized by tumor cells showing nuclear Wilms tumor 1 and calretinin staining and by strong membranous staining for cytokeratin CAM5.2. The results of staining for the epithelial markers carcinoembryonic antigen, thyroid transcription factor-1, MOC31, BerEP4, p63, p40, paired box 8, ER and PR were negative. BRCA1 associated protein 1 nuclear staining was lost in percentages similar to what has been reported for samples from Western countries.

CONCLUSIONS

Our findings suggest that MM-especially in its pleural localization-is often misdiagnosed in eastern China. Identifying pitfalls and possible solutions in the pathological diagnosis of MM will affect both the standard of care and research in China.

Designing a broad-spectrum integrative approach for cancer prevention and treatment

Targeted therapies and the consequent adoption of "personalized" oncology have achieved notable successes in some cancers; however, significant problems remain with this approach. Many targeted therapies are highly toxic, costs are extremely high, and most patients experience relapse after a few disease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistant immortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are not reliant upon the same mechanisms as those which have been targeted). To address these limitations, an international task force of 180 scientists was assembled to explore the concept of a low-toxicity "broad-spectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspects of relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a wide range of high-priority targets (74 in total) that could be modified to improve patient outcomes. For these targets, corresponding low-toxicity therapeutic approaches were then suggested, many of which were phytochemicals. Proposed actions on each target and all of the approaches were further reviewed for known effects on other hallmark areas and the tumor microenvironment. Potential contrary or procarcinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixed evidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of the relationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. This novel approach has potential to be relatively inexpensive, it should help us address stages and types of cancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for future research is offered.

Occupational and environmental exposures and cancers in developing countries

BACKGROUND

Over the past few decades, there has been a decline in cancers attributable to environmental and occupational carcinogens of asbestos, arsenic, and indoor and outdoor air pollution in high-income countries. For low- to middle-income countries (LMICs), however, these exposures are likely to increase as industrialization expands and populations grow.

OBJECTIVE

The aim of this study was to review the evidence on the cancer risks and burdens of selected environmental and occupational exposures in less-developed economies.

FINDINGS

A causal association has been established between asbestos exposure and mesothelioma and lung cancer. For arsenic exposure, there is strong evidence of bladder, skin, lung, liver, and kidney cancer effects. Women are at the highest risk for lung cancer due to indoor air pollution exposure; however, the carcinogenic effect on the risk for cancer in children has not been studied in these countries. Cancer risks associated with ambient air pollution remain the least studied in LMICs, although reported exposures are higher than World Health Organization, European, and US standards. Although some associations between lung cancer and ambient air pollutants have been reported, studies in LMICs are weak or subject to exposure misclassification. For pulmonary cancers, tobacco smoking and respiratory diseases have a positive synergistic effect on cancer risks.

CONCLUSIONS

A precise quantification of the burden of human cancer attributable to environmental and occupational exposures in LMICs is uncertain. Although the prevalence of carcinogenic exposures has been reported to be high in many such countries, the effects of the exposures have not been studied due to varying country-specific limitations, some of which include lack of resources and government support.

Mesothelin (MSLN) methylation and soluble mesothelin-related protein levels in a Chinese asbestos-exposed population

OBJECTIVES

This study investigated the mesothelin (MSLN) methylation and its relationship with soluble mesothelin-related protein (SMRP) levels in participants stratified by asbestos exposure scenarios and benign asbestos-related diseases (ARDs).

METHODS

The presence of benign ARDs was confirmed through chest X-ray and the asbestos exposure history was obtained using a standardized questionnaire in this study, including 262 participants. Sera SMRP were measured using MESOMARK, and MSLN methylation in genomic DNA extracted from whole blood was detected by real-time methylation-specific PCR. Covariates were compared with SMRP concentrations using correlation analysis and the potential covariates affecting SMRP were determined by multiple linear regression analysis, and the distribution of methylation status was analyzed by Chi-square test.

RESULTS

There was a trend toward elevation of SMRP values in healthy individuals exposed to asbestos as compared with those without asbestos exposure. The highest median level of SMRP was 1.3 nM in subjects with asbestosis, followed by cases with pleura plaque and asbestosis (1.2 nM), pleura plaque (0.9 nM), healthy subjects with occupational exposure (0.9 nM), non-occupational exposure (0.8 nM), and mixed exposure (0.8 nM). Within asbestosis cases, those with higher profusion scores had higher SMRP values than those with lower profusion scores (1.6 vs. 0.8 nM). Based on multi-regression analysis, the trend toward elevation of SMRP remained significant in subjects with occupational exposure or in those with asbestosis, as compared with healthy subjects without exposure (p < 0.01), although body mass index had an effect on SMRP (p < 0.0001). Regardless of the differences in SMRP levels among these subgroups, MSLN methylation ranged from 80.5 to 92.5 %, with no significant difference. The elevated level of SMRP in asbestosis with higher profusion scores could not be attributed to low MSLN methylation status.

CONCLUSIONS

Our findings suggest that the elevation of SMRP is related to asbestos exposure and benign ARDs especially for cases with high profusion scores, which is independent of MSLN methylation.

Global mesothelioma epidemic: Trend and features

Background:

Mesothelioma incidence has taken epidemic proportions in various countries. The trend of the epidemic remains undefined.

Objective:

To collect the most recent available data on mesothelioma incidence in order to determine the present trend of the epidemic.

Materials and Methods:

Data of the Cancer and Mesothelioma Registries have been reviewed. In addition, numerous researchers were contacted to obtain supplementary information.

Results:

The highest incidence rates are reported from some countries in Europe (United Kingdom, The Netherlands, Malta, Belgium), and in Oceania (Australia, New Zealand). Relatively low incidence/mortality rates are reported from Japan and from Central Europe. In many countries a trend to increase continues to be observed. Data are not available for the mostly populous countries.

Conclusion:

Mesothelioma epidemic does not show signs of attenuation. The lack of data for a large majority of the world does not allow that the consciousness of the risks related to asbestos exposure is reached.

Exposure-specific lung cancer risks in Chinese chrysotile textile workers and mining workers

OBJECTIVE

Whether there is a difference in the exposure-response slope for lung cancer between mining workers and textile workers exposed to chrysotile has not been well documented. This study was carried out to evaluate exposure-specific lung cancer risks in Chinese chrysotile textile workers and mining workers.

SUBJECTS AND METHODS

A chrysotile mining worker cohort and a chrysotile textile worker cohort were observed concurrently for 26 years. Information on workers' vital status, occupational history and smoking habits were collected, and causes and dates of deaths were verified from death registries. Individual cumulative fiber exposures were estimated based on periodic dust/fiber measurements from different workshops, job title and duration, and categorized into four levels (Q1-Q4). Standardized mortality ratios (SMRs) for lung cancer were calculated and stratified by industry and job title with reference of the national rates. Cox proportional hazard models were fit to estimate the exposure-specific lung cancer risks upon adjustment for age and smoking, in which an external control cohort consisting of industrial workers without asbestos exposure was used as reference group for both textile and mining workers.

RESULTS

SMRs were almost consistent with exposure levels in terms of job titles and workshops. A clear exposure-response relationship between lung cancer mortality and exposure levels was observed in both cohorts. At low exposure levels (Q1 and Q2), textile workers displayed higher death risks of lung cancer than mining workers. However, similarly considerably high risks were observed at higher exposure levels, with hazard ratios of over 8 and 11 at Q3 and Q4, respectively, for both textile and mining workers, after both age and smoking were adjusted.

CONCLUSION

The chrysotile textile workers appeared to have a higher risk of lung cancer than the mining workers at a relatively low exposure level, but no difference was observed at a high exposure level, where both cohorts displayed a considerably high risk.

Cancer mortality in Chinese chrysotile asbestos miners: exposure-response relationships

Objective

This study was conducted to assess the relationship of mortality from lung cancer and other selected causes to asbestos exposure levels.

Methods

A cohort of 1539 male workers from a chrysotile mine in China was followed for 26 years. Data on vital status, occupation and smoking were collected from the mine records and individual contacts. Causes and dates of death were further verified from the local death registry. Individual cumulative fibre exposures (f-yr/ml) were estimated based on converted dust measurements and working years at specific workshops. Standardized mortality ratios (SMRs) for lung cancer, gastrointestinal (GI) cancer, all cancers and nonmalignant respiratory diseases (NMRD) stratified by employment years, estimated cumulative fibre exposures, and smoking, were calculated. Poisson models were fitted to determine exposure-response relationships between estimated fibre exposures and cause-specific mortality, adjusting for age and smoking.

Results

SMRs for lung cancer increased with employment years at entry to the study, by 3.5-fold in ≥10 years and 5.3-fold in ≥20 years compared with <10 years. A similar trend was seen for NMRD. Smokers had greater mortality from all causes than nonsmokers, but the latter also had slightly increased SMR for lung cancer. No excess lung cancer mortality was observed in cumulative exposures of <20 f-yrs/ml. However, significantly increased mortality was observed in smokers at the levels of ≥20 f-yrs/ml and above, and in nonsmokers at ≥100 f-yrs/ml and above. A similarly clear gradient was also displayed for NMRD. The exposure-response relationships with lung cancer and NMRD persisted in multivariate analysis. Moreover, a clear gradient was shown in GI cancer mortality when age and smoking were adjusted for.

Conclusion

There were clear exposure-response relationships in this cohort, which imply a causal link between chrysotile asbestos exposure and lung cancer and nonmalignant respiratory diseases, and possibly to gastrointestinal cancer, at least for smokers.

Mortality in chrysotile asbestos workers in China

PURPOSE OF REVIEW

China has been the world's top chrysotile asbestos consumer and producer. However, the national mortality rate for asbestos-related diseases, particularly from malignancies, is unknown. This review elaborates recent studies on cancer mortality and nonmalignant respiratory diseases in Chinese chrysotile asbestos workers.

RECENT FINDINGS

Studies conducted in asbestos products factory workers and miners have demonstrated strong associations between exposure to chrysotile and mortality rates for lung cancer and nonmalignant respiratory diseases. Mortality rates for lung cancer and nonmalignant respiratory diseases in both asbestos workers and miners are four and three times higher, respectively, than expected, which are greater than those seen in studies from western countries, likely a reflection of heavier exposures and less effective protection for workers. An increased risk of gastrointestinal cancer was also detected in chrysotile miners. There have been surprisingly few reported cases of mesothelioma, however, which could, at least partially, indicate a problem in diagnosis.

SUMMARY

Given the substantially increased death risks for lung cancer and nonmalignant respiratory diseases, urgent efforts must be made to implement occupational health and safety regulations and decrease workers' exposures to prevent a future heavier disease burden. Meanwhile, improvements in diagnostics and systematic recording of the incidence and mortality of asbestos-related diseases are needed.