Abstract
Background: Breast cancer is one of the most significant causes of death in women around the world. Circular RNAs (circRNAs), which are a novel class of conserved RNA molecules, are involved in the occurrence and development of various diseases, especially malignancies; however, researchers rarely report their roles in human breast cancer. Methods: In the present study, the differentially expressed levels of circRNAs in human breast cancer tissues and paired noncancerous tissues were screened by circRNA microarray. Hsa_circ_0043278 was downregulated 43-fold in breast cancer and was selected for further analysis. The expression of hsa_circ_0043278 was verified in breast cancer specimens and paired noncancerous tissues by quantitative reverse transcription polymerized chain reaction (qRT-PCR) technique. The relationship between the expression of hsa_circ_0043278 and the clinicopathological features was analyzed. Results: Among the 520 differentially expressed circRNAs, 292 significantly upregulated circRNAs and 228 downregulated circRNAs in the breast cancer tissues compared with the paired noncancerous tissues. The area under the receiver operating characteristic (ROC) curve of hsa_circ_0043278 was 0.690. The results of the bioinformatics prediction showed five target miRNAs that might be sponged by hsa_circ_0043278. The expression of hsa_circ_0043278 was associated with lymph node metastasis and histological type of the patient. Patients with lymph node metastasis have tumors with significantly downregulated expression of hsa_circ_0043278 (P=0.0201). Conclusions: Our results suggest that hsa_circ_0043278 is downregulated and may play a key role in human breast cancer.