Kruppel-like factor 17 (KLF17), a new member of the Kruppel-like factors (KLFs), has been reported to be a negative regulator of epithelial-mesenchymal transition (EMT) and metastasis in breast cancer. However, the biological role and clinical significance of KLF17 in lung adenocarcinoma has been less clear. In the present study, we showed that KLF17 expression was decreased in lung adenocarcinoma. Reduced expression of KLF17 was correlated significantly with a short survival time in patients with lung adenocarcinoma (P < 0.0001). Moreover, KLF17 expression was an independent prognostic indicator for patients with lung adenocarcinoma. KLF17 expression level was correlated with the tumor stage (P = 0.016) and tumor size (P = 0.001) in lung adenocarcinoma. Overexpression of KLF17 inhibited cell growth in A549 and PC-9 cell lines. In conclusion, it is possible that KLF17 inhibits tumor growth in lung adenocarcinoma. The reduced expression of KLF17 is a valuable prognostic indicator for patients with lung adenocarcinoma, and KLF17 could be a novel target for treatment of lung adenocarcinoma. (C) 2012 Elsevier Inc. All rights reserved.