Lung Tumors Cancer and Mesothelioma Among Asbestos Workers

Most people that are diagnosed with mesothelioma have been exposed to asbestos in the workplace.  One interesting study on point is called, "Mesothelioma and lung tumors attributable to asbestos among petroleum workers" by Valerio Gennaro, MD, Murray M. Finkelstein, MD, Marcello Ceppi, DSc, Vincenzo Fontana, DSc, Fabio Montanaro, DSc, Alessandra Perrotta, DSc, Riccardo Puntoni, DSc, Stefania Silvano, MD - American Journal of Industrial Medicine Volume 37 Issue 3, Pages 275 – 282.  Here is an excerpt: "Abstract - Background - Asbestos exposure has been definitively found to be associated with both mesothelioma and lung cancer. Nevertheless, in the overall population of oil refinery workers potentially exposed to asbestos, many studies clearly show a definitely increased risk of mesothelioma, but no proven excess of lung cancer after comparison to the general population. Through the presentation of new data and the re-appraisal of two recent and independent epidemiological studies conducted in Liguria, Italy, and Ontario, Canada, we attempt to shed light on this apparently paradoxical finding.  - Methods  - Lung cancer mortality was studied among maintenance workers exposed to asbestos, and among two other subgroups of refinery employees: blue collar and white collar workers. The comparison with blue collar workers was performed in order to take into account the role of healthy worker effect, smoking habit, and the socioeconomic level. The comparison with white collar workers was performed to control for other occupational lung carcinogens.

Results and Conclusions - Results reveal a consistency between the two studies and show that 96-100% of the mesotheliomas and 42-49% of the lung tumors arising among maintenance workers were attributable to asbestos exposure.

Another interesting study is called, "Role of Oxyradicals in Mutagenicity and DNA Damage Induced by Crocidolite Asbestos in Mammalian Cells" by An Xu, Li-Jun Wu, Regina M. Santella, and Tom K. Hei - Cancer Res December 1, 1999 59; 5922.  Here is an excerpt: "Abstract - Crocidolite, one of the most carcinogenic forms of asbestos, is mutagenic in cultured mammalian cells when assayed using a system that can detect multilocus deletions. In the present study, we examined the effect of buthionine sulfoximine (BSO) on mutation frequency and the formation of 8- hydroxydeoxyguanosine (8-OHdG) in human-hamster hybrid (AL) cells induced by crocidolite fibers in an attempt to determine the role of oxyradicals in mediating fiber mutagenesis. BSO, a competitive inhibitor of the enzyme γ-glutamyl cysteine synthetase, depleted nonprotein sulfhydryls to <5% of control within 24 h at a nonmutagenic dose of 25 μm. In cells pretreated with BSO for 24 h, the mutation yield at the CD59 locus induced by a 4 μg/cm2 dose of crocidolite fibers was increased by more than 3-fold (P < 0.05). Using immunoperoxidase staining with a monoclonal antibody specific for 8-OHdG, we demonstrated that crocidolite fibers induced a dose-dependent increase in oxidative DNA damage in AL cells. Furthermore, addition of DMSO, a well-established hydroxyl radical (OH•) scavenger, dramatically suppressed 8-OHdG induction (P < 0.005). Our results definitely demonstrate that reactive oxygen species mediate fiber-induced DNA damage mutagenesis in AL cells in a concentration-dependent manner.

A third study worth examining is called, "Worker Exposure to Asbestos During Removal of Sprayed Material and Renovation Activity in Buildings Containing Sprayed Material" by Nam Won Paik; Richard J. Walcott; and Patricia A. Brogan - American Industrial Hygiene Association Journal, Volume 44, Issue 6 June 1983, pages 428 – 432.  Here is an excerpt: "Abstract - Contents and types of asbestos in fireproofing insulation materials sprayed on ceilings of 127 buildings throughout the U.S. were studied. Asbestos was found to be present in more than 50% of the buildings and chrysotile was the main component identified. Frequency distribution of airborne fiber concentrations was lognormal. During renovation activities by various workers, including sheet-metal workers, carpenters and electricians, average fiber concentrations at workers' breathing zones were less than 2 fibers/cc, but exceeded 0.1 fibers/cc. During removal of sprayed materials, workers were exposed to extremely high concentrations (average 16.4 fibers/cc) when dry methods were used. When wet methods were used during removal, the airborne fiber concentrations were sharply reduced to less than 2 fibers/cc."

If you found any of these excerpts, please read the studies in their entirety.