In the univariate survival analysis, high TNM stage (P = 0.003 and P = 0.001), poor tumor differentiation (P = 0.009 and P = 0.002) and AREG expression (P = 0.021 and P = 0.003) were significant adverse prognostic factors for DFS and OS, respectively (Table 3, Fig. 2). This evidence concerns the gene AREG and neoplasm.