Lung cancer in chronic obstructive pulmonary disease patients, it is not just the cigarette smoke

Purpose of review An important association has been described between chronic obstructive pulmonary disease (COPD) and lung cancer, where different mechanisms have been proposed. There is no unique cause for this association, as COPD is by itself a heterogeneous disease, in which their classical phenotypes (i.e., emphysema and chronic bronchitis) each play an important role in lung cancer development. We will discuss recent evidence that links these two diseases and specific characteristics found in lung cancers from patients with COPD. Recent findings Molecular studies have found specific gene expressions (reduction and overexpression) in lung tumors from patients with COPD, which likely predispose to increased methylation during lung carcinogenesis, and are associated with aggressiveness. Recent evidence suggests that lung cancer risk is higher in individuals with long telomeres, and that this effect takes place well in advance of diagnosis. Lung cancer is likely to develop in areas of the lung with greater emphysema and the severity of the latter is associated with larger and more aggressive tumors. Summary Clinical and molecular studies have found that lung cancers that develop in patients with COPD and/or emphysema appear to be more aggressive and have a distinct molecular profile when compared with tumors from patients without an underlying lung disease. This could have important implications when deciding on personalized treatments.