Association of biogenic silica with disease.

Certain plants contain structures consisting of biogenic silica. This form of silica has been implicated as a causative agent in the high esophageal cancer areas of southern Africa, northeast Iran, and northern China. A spicule shape of biogenic silica is known to act as a tumor promoter in the mouse skin model system. The observation that fine biogenic silica fibers are found in leaves of sugarcane may pose a hazard for cane workers; also, the discovery that bracken contains silica fibers could have implications for browsing cattle. This paper reviews and discusses the involvement of biogenic silica in disease.