Statistical analyses were performed using SPSS 17.0 software (SPSS Inc., Chicago, IL, USA) and GraphPad Prism 5.0 (GraphPad software Inc., La Jolla, CA, USA). Survival curves were plotted using Kaplan–Meier estimates. Wilcoxon rank sum test was used for statistical analysis of clinical scores; χ2 (chi-square) test was applied in studying the correlation between γH2AX and p-DNA-PKcs, and p-DNA-PKcs and p-AKT. Comparisons between 2 groups were performed using the Student's t test. Bivariate correlations between study variables were calculated by Pearson's correlation coefficients. One-way ANOVA test was used for statistical analysis of remaining data. All tests were two-tailed Data are presented as means ± SD. P < 0.05 was considered statistically significant.