NDRG4 and neoplasm: As shown in Table 2, Kaplan-Meier survival analysis showed that six clinicopathological characteristics were significantly associated with OS, including age (P = 0.001), tumor size (P = 0.007), lymph node metastasis (P = 0.004), TNM stage (P = 0.001), disease recurrence (P = 0.009), and NDRG4 promoter hypermethylation (P = 0.002, Figure 3A).