MLH1 and metastatic malignant neoplasm in the lymph nodes: Multivariate logistic regression analysis found that the increased immunohistochemical staining intensity of MLH1 was a protective factor in non-metastatic patients (OR: 0.969, 95 %CI 0.945–0.994, P = 0.015), and the loss of MLH1 expression might lead to 253 lymph node metastasis.