MLH1 and metastatic malignant neoplasm in the lymph nodes: To further reduce the number of variables, we performed LASSO regression analysis, which yielded 23 variables identified (Figures 4A, B) and eight critical variables (tumor size, pre-operative serium CEA, distant metastasis in NCRT, nerve invasion, age, vascular invasion, preoperative lymph node metastasis, MLH1) were identified using a Venn diagram by four methods (Figure 4C).