Asbestos Bodies and Mesothelioma

The relation between exposure to asbestos and the occurrence of neoplasia is reviewed and it is concluded that the increasing use of asbestos will result in an increasing incidence of tumours. It is known that inhalation of asbestos fibres results in the formation of asbestos bodies in the lungs. Typical asbestos initiated tumours—pleural and peritoneal mesothelioma—were found at an unusually high frequency in shipyard-workers. Only slight asbestos exposure had taken place in these cases. On the other hand the persons involved had been exposed to high concentrations of iron oxide (flame cutters and welders). Objects similar to asbestos bodies were found in their lungs. Originally it was thought that these were pseudo asbestos bodies, containing an iron oxide core, and it was suspected that pseudo asbestos bodies might play a part in the genesis of the tumours. Investigations carried out at TNO institutes showed that the kernel of the bodies contained asbestos of the amphibole type thus proving that they were not pseudo but normal asbestos bodies. The simultaneous exposure to low concentrations of asbestos and high concentrations of iron oxide raises the suspicion that iron oxide might be an important cofactor in the genesis of mesothelioma found in the shipyard-workers. Experiments with different types of asbestos and iron oxide, on animals, are considered to be highly desirable in order to verify or disprove this hypothesis.