Expression of transforming growth factor ß1 and e-cadherin in lung adenocarcinoma J. Yoo * , S. Y. Park * St. Vincent's Hospital, Pathology, Suwon, Republic of Korea Objective: There is evidence supporting the concept of tumor progression from pulmonary adenocarcinoma in situ (formerly bronchioloalveolar carcinoma, BAC) to adenocarcinoma with varying degrees of invasion. The aim of this study was to investigate the role of TGFß1in tumor invasiveness in lung adenocarcinoma, and to determine the potential relationships between its expression and immunophenotypes of cell adhesion molecules. Method: Tumor samples (n=40) from adenocarcinoma in situ (n=13), minimally invasive adenocarcinoma (formerly BAC with ≤5 mm invasion, n=2), and lepidic predominant invasive adenocarcinoma (formerly mixed adenocarcinoma showing non-mucinous BAC features with >5 mm invasion, n=25) were examined for the expression of TGFß1, E-cadherin, N-cadherin, and H-cadherin proteins using immunohistochemistry. Results: Twenty-five tumors (63 %) were positive for TGFß1. The frequency of immunoreactivity in patients with adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant invasive adenocarcinoma was 23 % (3/13), 50 % (1/2), and 84 % (21/25), respectively (p=0.001).