ABSTRACT
The issue of whether chrysotile asbestos causes mesothelioma has largely been related to the studies of J. C. Wagner, F. D. Pooley and Mitha, A. Churg, B. T. Mossman and J. C. McDonald and others. The “amphibole hypothesis” is based on scientific and epidemiologic evidence that pure chrysotile without amphibole contamination does not cause mesothelioma. Earlier studies had suggested that chrysotile might cause mesothelioma, and there was caution during the 1960s about chrysotile as an adequate replacement for crocidolite asbestos. The availability of compounds that modulate epigenetic modifications, such as histone acetylation or DNA methylation, offers new prospects for the treatment of malignant pleural mesothelioma. Interest in Mendelian genetic transmission has largely been supplanted by interest in epigenetics, since only a small percentage of mesotheliomas are familial in the United States, as compared with some areas of Turkey. Increasing evidence indicates that unresponsiveness to chemotherapy of mesotheliomas is due to epigenetic errors leading to inadequate gene expression in tumor cells.
