Quantitative Analysis of Asbestos Burden in a Series of Individuals with Lung Cancer and a History of Exposure to Asbestos

Asbestos is recognized as a lung carcinogen. In the present study, tissue from 20 individuals who died from lung cancer and who had a history of exposure to asbestos was evaluated for the presence of asbestos bodies and uncoated asbestos fibers. A digestion procedure was used to isolate the particulates from the tissue. The samples were evaluated by light microcopy to quantify the numbers of ferruginous bodies in the tissue. The uncoated fibers (which included all fibers equal to or greater than 0.5 microm) were analyzed by analytical transmission electron microscopy. Seventeen of the 20 cases were positive for ferruginous bodies (which were morphologically consistent with asbestos bodies). Five of these were found to have concentrations within the range used in our laboratory for the general population (<20 ferruginous bodies/g wet tissue). Nineteen of the 20 cases were found to have asbestos fibers in the higher magnification scan (either 16 K or 20 K). Some of the asbestos fibers identified were specific for the types of exposures that were reported. Most individuals in this study were found to have mixed populations of asbestos fibers in the lung tissue. This suggests that when there are exposures to products containing commercial asbestos there are likely exposures to dust containing noncommercial asbestos. A contrast exists in the dust burden within the lung of these individuals as compared to samples from the general population in that occupational or "occupational-like" exposures such as in these cases are often reflected by the presence of longer fibers of asbestos in the tissue.