The activity of metal-dependent superoxide dismutase as a predictive factor in patients with hepatocellular carcinoma

Abstract

Abstract Background: Oxidative stress is one risk factor for hepatocellular carcinoma (HCC). Oxide dismutase (SOD) is an important index to evaluate oxidative stress process. However, the cut-off value of diagnosis and the prediction of mortality in hepatocellular carcinoma (HCC) based on serum total SOD activity are unclear. Methods: Serum total SOD activity were analyzed in HCC patients (n = 124) and control subjects (n = 117). Mn, Fe, Cu, Zn and Se were detected by limiting dilution method using Agilent 7900 Inductively Coupled Plasma Mass spectrometry (ICP-MS). Receiver operating characteristic (ROC) curves was used to determine cutoff values of serum total SOD activity for the diagnosis of HCC. Overall survival (OS) were determined via the Kaplan-Meier method. Results: In model groups, the cut-off level of total SOD activity for HCC was 169.2 U/mL (Sensitivity:87.23%, Specificity:91.95%), while for HCC (AFP<20 ng/ml) it was 173.4 U/mL (Sensitivity:86.79%, Specificity:88.51%). Additionally, in the validation groups, the true positive rate, the true negative rate and the accuracy rate were all above 90%. According to the cutoff value of SOD, the HCC patients were assigned to an H-SOD and L-SOD group depending on their serum total SOD activity at admission before operation. The 5-year overall survival (OS) rate of the H-SOD group was 75.00% and that of the L-SOD group 36.59% in HCC patients (p=0.0245). Accompanied by a decrease in SOD activity, the serum levels of Zn (t=3.890, p=0.0003) and Se (t=7.694, p<0.0001) were also signifificantly decreased and correlated positively with SOD activity (both p<0.05) in HCC patients. Conclusions: Low serum total SOD activity may also be a risk factor for HCC. HCC patients with low serum total SOD activity might have poor prognoses for survival. The decrease of SOD activity in HCC patients was partly related to a lack of Zn and Se.