Lung adenocarcinoma (LUAD) is one of the most common types of lung cancer, which affects the life and health of patients. The role of ATP-binding cassette subfamily A member 3 (ABCA3) in the occurrence and development of LUAD is unclear; therefore, ABCA3 expression in LUAD and other tumors was analyzed in the present study. In addition, ABCA3 expression in patients with LUAD and their survival were analyzed using a public database. ABCA3 co-expressed genes were identified and their enriched pathways were analyzed. Furthermore, ABCA3 expression was knocked down in LUAD cell lines. The proliferation, invasion and migration of cells, and the process of epithelial-mesenchymal transition (EMT), were studied through cytological and molecular biology experiments. Compared with that in normal lung tissues, ABCA3 expression was significantly reduced in tumor tissues. Patients with low ABCA3 expression had a markedly worse overall survival compared with those with high ABCA3 expression. Notably, abnormal ABCA3 expression has been observed in a variety of tumors. Subsequently, multiple pathophysiological pathways enriched by ABCA3 and its co-expressed genes were explored. Furthermore, the malignant behavior of tumor cells was enhanced when ABCA3 expression was knocked down, and the EMT process was activated after ABCA3 expression was knocked down. In conclusion, as a tumor suppressor gene, ABCA3 serves a protective role in the development of tumors, and may have a potential role in clinical applications, and thus, is worthy of further study.Copyright: © Song et al.