As aldehyde dehydrogenases (ALDHs) scavenge aldehydes during lipid peroxidation and are highly active in lung cancer [31], increased expression of ALDH1A1 and ALDH3A1 has been noted in squamous cell carcinomas and adenocarcinomas of the lung, as well as in atypical pneumocytes of nonsmokers and in normal pneumocytes of smokers [32,33]. This evidence concerns the gene ALDH3A1 and lung cancer.