Furthermore, high expression of MutT-related proteins was significantly associated with AJCC stage and lymph node metastasis of CRC specimens (Table 1), and a Kaplan-Meier analysis showed that CRC patients with high expression of MTH1, MTH2 or NUDT5 had a significantly lower OS after surgical resection than those with low expression (Figure 4). This evidence concerns the gene NUDT1 and metastasis.