Respiratory malignancies induced by asbestos exposure and evaluation of cases with typical pleural malignant mesothelioma and lung cancer with asbestosis

Asbestos exposure induces lung fibrosis, i.e. asbestosis, and furthermore, pathological changes of pleura, i.e. asbestos pleurisy of pleural plaque. Generally, asbestosis is induced by massive exposure to asbestos and pleural changes are induced by low dose exposure to asbestos. The most important diseases which are induced by asbestos exposure are malignancies, especially malignant mesothelioma and lung cancer. Two cases, one malignant mesothelioma, the other lung cancer with asbestosis induced by asbestos exposure received almost the same dose of asbestos, as estimated from the period of asbestos exposure and occupational history and the same kind of asbestos (crocidolite) and had a smoking history. We do not know which elements may induce malignancies under asbestos exposure. Recently, some reports described that asbestos mediated the transformation of genes and this action induced malignancies. We should extend our study to the gene problem in cases of malignant mesothelioma and lung cancer induced by asbestos exposure.