Mechanistic links between COPD and lung cancer.

Numerous epidemiological studies have consistently linked the presence of chronic obstructive pulmonary disease (COPD) to the development of lung cancer, independently of cigarette smoking dosage. The mechanistic explanation for this remains poorly understood. Progress towards uncovering this link has been hampered by the heterogeneous nature of the two disorders: each is characterized by multiple sub-phenotypes of disease. In this Review, I discuss the nature of the link between the two diseases and consider specific mechanisms that operate in both COPD and lung cancer, some of which might represent either chemopreventive or chemotherapeutic targets.