APEX1 and neoplasm: However, participants with the APE1 Asp/Asp genotype had an OR of 2.15 (95% CI, 1.19–3.87; P = 0.011) for the risk of p53 mutation as compared with those with the APE1 Asp/Glu + Glu/Glu genotype after adjusting for covariates, including sex, smoking status, and tumor histology and stage (Table 3).