APEX1 and hepatocellular carcinoma: Western blot analyses of nuclear (NCE) and mitochondrial (MCE) protein extracts from non-tumor (Distal) and HCC (Tumor) confirmed that Grades 1 and 2 were characterized by a significantly higher amount of APE1 in mitochondria in the tumor compared to the distal area of all patients, while Grade 3 showed the opposite pattern (Fig. 1d and Supplementary Figure 1).