The protein levels of CYP11A1, ALDH3B1, ALDH2, GSTO2, GPX3 and IDH2 in PA (PA1, PA2, PA3 and PA4) and control samples (C1, C2, C3 and C4) were detected by Western blot. GAPDH was served as a loading control. Statistical significance was evaluated using the Student’s t-test. *P < 0.05, **P < 0.01, ***P < 0.001.