Slug is a significant EMT inducer that has been implicated in the progression of lung cancer.39 When overexpressed, Slug abrogates E‐cadherin‐mediated intercellular adhesion and promotes tumor cell invasion.40 Slug overexpression was found to be correlated with both poor disease‐free survival and OS in lung cancer.41, 42, 43 In this study, Slug overexpression was significantly related to high pathologic differentiation, a high pathologic T stage, the presence of VPI, and increased lymph node metastasis. This evidence concerns the gene CDH1 and metastatic malignant neoplasm in the lymph nodes.