APEX1 and gallbladder cancer: The mean relative expression levels (IDV) of the regular form of APE1 (37 kDa) in normal gallbladder, chronic cholecystitis, and gallbladder cancer were 0.39 ± 0.01, 0.65 ± 0.45, and 0.75 ± 0.32 (mean ± SEM), respectively and for APE1 variant (35 kDa) were 0.36 ± 0.03, 0.28 ± 0.04 and 0.37 ± 0.02, respectively.