Introduction. We investigated the expression of microRNAs and mRNAs in pleural tissues from patients with either malignant pleural mesothelioma or benign asbestos-related pleural effusion.Methods. Fresh frozen tissues from a total of 18 malignant pleural mesothelioma and 6 benign asbestos-related pleural effusion patients were studied. Expression profiling of mRNA and microRNA was performed using standard protocols.Results. We discovered significant upregulation of multiple microRNAs in malignant pleural mesothelioma compared to benign asbestos-related pleural effusion. Hsa-miR-484, hsa-miR-320, hsa-let-7a, and hsa-miR-125a-5p were able to discriminate malignant from benign disease. Dynamically regulated mRNAs were also identified. MET was the most highly overexpressed gene in malignant pleural mesothelioma compared to benign asbestos-related pleural effusion. Integrated analyses examining microRNA-mRNA interactions suggested multiple altered targets within the Notch signaling pathway.Conclusions. Specific microRNAs and mRNAs may have diagnostic utility in differentiating patients with malignant pleural mesothelioma from benign asbestos-related pleural effusion. These studies may be particularly helpful in patients who reside in a region with a high incidence of mesothelioma.

Significance: We found that the probability of carrying heterozygous germline BLM mutations is significantly higher among mesothelioma patients than in the general population. In vitro and in vivo experiments suggest that heterozygous BLM mutations increase susceptibility to mesothelioma. BLM -mutation carriers are at higher risk of developing mesothelioma, and their risk increases upon asbestos exposure. Therefore, BLM mutation carriers should benefit from prevention and screening for early detection. We suggest that genetic testing to identify carriers of BLM heterozygous mutations and genetic counseling would help identify individuals at higher risk of mesothelioma and provide mutation carriers the option to implement simple preventive measures to reduce exposure to asbestos and other carcinogenic fibers to decrease their risk of developing mesothelioma.

Malignant mesothelioma (MM) is an important health problem due to ongoing asbestos exposure. Environmental asbestos exposure leads to a high risk of MM in Turkey. The Turkish Mesothelioma Working Group and the Turkish Public Health Institute designed and performed the Turkey National Mesothelioma Surveillance and Environmental Asbestos Exposure Control Program (TUNMES-EAECP). The aim of this study was to analyze the results of the TUNMES-EAECP. Patients diagnosed with MM (code C45.0–C45.9) between 2008 and 2012 were identified. The “from case to the field” method was used to determine the villages with current or previous asbestos exposure. Special public health teams took soil samples from these villages, which were then examined using an X-ray diffractometer. Direct Standardized Average Annual Mesothelioma Incidence Rate (AMIR) and relative risk (RR) of MM were calculated. Finally, a projection on the incidence of MM between 2013 and 2033 was made. The number of confirmed MM cases was 5617 with a male to female ratio of 1.36. Mean age was 61.7 ± 13.4 (20–96) years. The median survival was eight (95% CI 7.6–8.4) months. Asbestos exposure continues in 379 villages, with 158,068 people still living in high risk areas. The standardized AMIR was 2.33/100,000 per year. The risk of MM was higher in males, in both sexes over the age of 40, in asbestos-containing provinces, and in those where the TUNMES was organized. Among the population with continuing asbestos exposure in rural areas, the number of MM cases between 2013 and 2033 was estimated as 2511. As such, the incidence of MM in Turkey is as high as in industrialized countries. Asbestos exposure in rural areas continues to be a serious problem in Turkey, which obviates the necessity for effective preventive measures.

Apart from living near an asbestos industry site, mine, or in an asbestos-contaminated house, environmental asbestos exposure is observed in certain regions where the (natural) soil is 'contaminated' with asbestos (fibers). In this essay, we review the association between environmental asbestos exposure and lung cancer in Turkey. Other studies have also suggested that environmental asbestos exposure is able to increase the risk of lung cancer. Lung cancer associated with environmental asbestos exposure seems to be diagnosed at a younger age, and the risk for women is in the same range as that for men. Our data indicate that the relationship between exposure dose and risk is linear and that a safe threshold cannot be established. Therefore, people living in areas with increased chances of environmental asbestos exposure should be mentored to take part in smoking cessation programs and considered candidates for inclusion in lung cancer screening programs. There is an obvious need for additional studies on this topic.

We evaluated possible diagnostic and prognostic values of serum midkine in malignant pleural mesothelioma in comparison with those of serum mesothelin, a well-established diagnostic biomarker. Serum mesothelin and midkine levels were determined with an enzyme-linked immunosorbent assay. We examined specimens from 95 Turkish cases with malignant pleural mesothelioma, 56 metastatic cancers to pleura, 27 other types of benign pleural diseases and 20 benign asbestos pleurisy. The cut-off values were 1.5 nmol/L for mesothelin and 421 pg/mL for midkine. Sensitivity and specificity of mesothelin were 51.6 and 71.4%, 51.6 and 85.2%, and 51.6 and 85% for differentiating mesothelioma from metastatic cancers to pleura, other benign pleural diseases and benign asbestos pleurisy, respectively. Sensitivity and specificity of midkine were 61.1 and 41.1%, 61.1 and 48.1%, and 61.1 and 75% to distinguish mesothelioma from metastatic cancers to pleura, other benign pleural diseases and benign asbestos pleurisy, respectively. Combination of both biomarkers did not improve the differential diagnostic efficacy. Mesothelin levels were elevated in the epitheloid type and in the advanced cases, but were not related to the prognosis. In contrast, elevated baseline levels of midkine were independently associated with a poor prognosis of mesothelioma patients after adjusting for the stage, the histological subtypes and treatment schedules (HR = 1.84; 95% CI: 1.09-3.09) (p = 0.022). Serum mesothelin showed moderate sensitivity and high specificity to differentiate malignant pleural mesothelioma from metastatic malignancy to pleura and from benign pleural diseases. In contrast, midkine was a useful marker for predicting prognosis of mesothelioma patients.