APEX1 and lung cancer: Most of these studies were case-control studies that found an association between hOGG1 Ser326Cys polymorphism and increased lung cancer risk16–20; however, most found no association between APE1 Asp148Glu polymorphism and lung cancer risk.16,21–23 The exception was 1 report that showed that APE1 Asp148Glu polymorphism was associated with lung cancer risk after adjusting for age, sex, and smoking.24 Interestingly, the hOGG1 and APE1 genetic polymorphisms were significantly associated with lung cancer risk in heavy smokers but not in light smokers or nonsmokers.16–22