OBJECTIVERecently, long noncoding RNAs (lncRNAs) have got much attention for their role in tumor progression. LncRNA AFAP1-AS1 was studied in this research to identify how it affects the development and proliferation of osteosarcoma.PATIENTS AND METHODSThe mRNA expression of AFAP1-AS1 in osteosarcoma cells and tissue samples was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, cell proliferation assay and Matrigel assay were performed. Furthermore, the underlying mechanism was explored by using qRT-PCR and Western blot assay.RESULTSThe expression level of AFAP1-AS1 was higher in osteosarcoma samples than that in adjacent tissues. In addition, the proliferation and invasion were inhibited after AFAP1-AS1 was downregulated in vitro. Besides, the mRNA and protein expression levels of brain derived neurotrophic factor (BDNF) were reduced after downregulation of AFAP1-AS1. Furthermore, the expression level of BDNF was positively related to the expression of AFAP1-AS1 in osteosarcoma tissues.CONCLUSIONSAFAP1-AS1 could enhance the proliferation and invasion of osteosarcoma cells by upregulating BDNF, which might be a potential therapeutic target in osteosarcoma.