Elucidation of Asbestos-induced Mesothelial Carcinogenesis toward Its Prevention

Abstract

Human exposure to asbestos fibers has been associated with diffuse malignant mesothelioma (DMM) in the pleural and abdominal cavity. Despite advancements in the molecular analyses of human cases of DMM and animal models, the understanding of the carcinogenic mechanisms remains still limited. There are basically three hypotheses regarding the pathogenesis of asbestos-induced DMM, which may be integrated as follows; (1) the “oxidative stress theory” is based on the fact that phagocytic cells that engulf asbestos fibers produce large amounts of reactive oxygen species (ROS) due to their inability to digest the fibers, and that iron contained in crocidolite and amosite fibers works as a catalyst for the generation of ROS, (2) the “chromosome tangling theory” postulates that asbestos fibers impair the equivalent distribution of chromosomes during mitosis, and (3) the “theory of adsorbing many specific proteins as well as carcinogenic molecules” states that asbestos fibers in vivo concentrate specific proteins or chemicals including the components of cigarette smoke and radioactive chemical element. Recent studies suggest that local iron overload is a key event. Elucidation of the major mechanisms underlying DMM would be helpful for the development of strategies to prevent DMM generation in people who have been exposed to asbestos.