In  US, 90% lung cancers were caused by smoking. It’s estimated that the incidence of lung cancer is 200,000 each year and 150,000 deaths were caused by lung cancer each year. Some died after 30 year smoking, but others lives to 80 or 90 years fine.  It seems that smoking gene may related to smoking addiction, but another gene(s) may coplay with the smoking gene to induce lung cancer. It’s interesting to know among heavy smokers what percent will  develop lung cancer, or the individual smoking- lung cancer risk.