The epithelial-mesenchymal transition phenotype is associated with the frequency of tumor spread through air spaces (STAS) and a High risk of recurrence after resection of lung carcinoma

•We analyzed EMT phenotypes in patients with therapy-naive lung carcinoma.•STAS was less frequently observed in tumors with epithelial phenotype.•EMT phenotype was independent prognostic factor of recurrence in STAS patients. The prognostic value of spread through air spaces (STAS) in lung carcinoma has been validated in independent cohorts. Epithelial-mesenchymal transition (EMT) is a biological process that promotes the migration and invasiveness of tumor cells. To investigate the role of the EMT phenotype in the occurrence of STAS, we analyzed patients with therapy-naive lung adenocarcinoma and squamous cell carcinoma undergoing lobectomy (n = 635). STAS was defined by the presence of tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. The expression of E-cadherin, vimentin, and ®-catenin was evaluated by immunohistochemistry using tissue microarray. Tumors were classified into three EMT phenotypes (epithelial, intermediate, and mesenchymal). Recurrence-free probability and overall survival were analyzed using the log-rank test and the Cox proportional hazards model. STAS was less frequently observed in tumors with epithelial phenotype than in those with non-epithelial phenotype (p = 0.034), and more frequent in patients with nuclear β-catenin-positive tumors (p