Figure 2.

Field of cancerization and field of injury theories of lung cancer development. Field of cancerization is based upon the replacement of normal pulmonary cells by tumorigenic cells upon exposure to carcinogens. These cells go on to produce genetic aberrations, ultimately leading to carcinogenesis in the exposed areas of the lungs. Field of injury-mediated tumorigenesis is an outcome of carcinogen-induced genetic mutations and tissue injury as a result of extensive host response. These carcinogen-induced tumorigenic lesions are not restricted to a particular region or field (as in field of cancerization) but are widespread in the entire respiratory tract and lungs.