Similarly, the cut-off value for plasma APE1/Ref-1 level for diagnosis of atherosclerosis in ApoE−/− mice fed with a Western-type diet (WD) as compared with ApoE−/− mice fed with a normal diet (ND) was set at 5.64 ng/mL, with an area under ROC curve of 1.0, a sensitivity of 100%, and a specificity of 90%. Here, APEX1 is linked to atherosclerosis.