APEX1 and metastatic malignant neoplasm in the lymph nodes: As for the expression of APE1 stratified by the lymph node metastasis, patients with lymph node metastasis in APE1 positive cases have poor prognosis for OS (MST: 12.0 vs.18.0 months; P=0.036) (Figure 2C) (Supplemental Table 5).