The mechanism of lung cancer oncogenes inducing carcinogenesis is not yet fully understood, but some oncogenes such as ras and myc gene families and c-erbB2 are now known to be associated with the development of lung cancer. However, the development of lung cancer is triggered by a combination of internal and external factors, including exogenous mutations in cells, overexpression of proto-oncogenes and suppression of oncogenes. Therefore it only suggests that patients with lung cancer may have a genetic predisposition.