Air pollution and respiratory pathology: lung cancer

Lung cancer is the most frequent cause of death from neoplastic pathology in the western world (28% of total mortality from neoplasia); in 90% of cases it is caused by tobacco smoke. In Italy, a stabilisation trend in males is observed, while female mortality is still increasing. During the first two decades of 2000, a more or less evident pathology decline is expected in males and a decline/stabilisation in females, according to the results of anti-smoking and anti-pollution campaigns. Lung cancer can be considered a pathology of multifactorial etiopathogenesis, where out- and indoor environmental risk factors, together with genetic factors and living habits, combine to explain the differences in increase of neoplasy incidence in exposed populations and categories. Several chemical, physical and biological agents have been identified as promoting or initiating factors of a series of genic modifications inducing "genetic instability" and subsequent alteration of the programmed cell death regulation ("apoptosis") and of the cell cycle responsible for somatic cell alterations ("transformed phenotype") in previously normal tissues. This paper outlines the different risk factors responsible for lung neoplasies, and discusses the molecular-biological mechanisms involved in the pathogenesis of lung cancer.