Inorganic particles in human tissues and their association with neoplastic disease.

An increased gastrointestinal cancer risk is associated with occupational exposure to asbestos fiber. Examination of tissues obtained from extrapulmonary organs of exposed workmen demonstrates the presence of asbestos fibers and bodies. The amount of fiber present in these tissues is many magnitudes less than encountered in the lung tissues from the same individuals. Ingestion of asbestos fiber in some environmental instances may approach in magnitude the amount resulting from occupational exposure. Disease factors are discussed.