The lung is a site for repeated or chronic inflammatory insults. Epidemiologic research has provided evidence to support the hypothesis that tissue damage caused by inflammation can initiate or promote the development of lung cancer, possibly in conjunction with tobacco use. For example, some studies suggest an increased risk of lung cancer among persons with lung infections, such as tuberculosis, bacterial pneumonia, or inflammatory lung diseases. Elevated serum levels of C-reactive protein, an inflammation marker, are associated with heightened lung cancer risk. Recent studies also demonstrate increased lung cancer risk among immunosuppressed individuals infected with HIV. Other research indicates an association between genetic polymorphisms in the inflammation pathway, which might modulate the inflammatory response and lung cancer risk.