Smoking is the principal inductor of an inflammatory process known as chronic obstructive pulmonary disease (COPD), which is considered a risk factor to develop lung cancer; moreover, the inflammation derived from COPD and the overexpression of HIF-1α potentiate the activation of KRAS signaling, which in turn induce tumorigenesis. The gene discussed is KRAS; the disease is chronic obstructive pulmonary disease.