Long noncoding RNA (LncRNA) has been shown to mediate the development of human malignancies. However, data on its role in breast cancer remains scant. We aimed to evaluate the prognostic potential of lncRNAs in breast cancer.We downloaded data on breast cancer patients from The Cancer Genome Atlas (TCGA) database. Tissues were obtained from The Fifth People's Hospital of Chengdu. We then used the DESeq2 package to profile the expression of the lncRNAs between the patients and normal samples. Besides, we performed prognosis and survival analysis using survival tools in R package. We then assayed the role of the differentially expressed lncRNAs, AC012213.3 (ENSG00000266289), in cancer cell lines. Quantitative real-time PCR and Western blot analysis were performed to evaluate the expression of the gene in the cell lines and then assessed its role in the progression of breast cancer using cell proliferation (CCK8 and colony formation assays), migration, invasion (transwell and wound-healing assays) and apoptotic (flow cytometry) assays.Our data showed high expression of lncRNA AC012213.3 in breast cancer tissues and cell lines. The high expression of the AC012213.3 was associated with the worse prognosis and clinical features. Besides, in vitro assays demonstrated that downregulation of AC012213.3 suppresses the proliferation and invasion of breast cancer cells. Further analysis showed that RAD54B is a downstream AC012213.3 target gene and was upregulated in breast cancer. Interestingly, RAD54B expression was associated with shorter survival in breast cancer. In addition, AC012213.3 was shown to facilitate breast cancer progression through the RAD54B/PI3K/AKT axis.Taken together, our data demonstrated that lncRNA AC012213.3 is upregulated in breast cancer and could enhance breast cancer progression through RAD54B/PI3K/AKT axis.© 2021 Zhong et al.