Altered expression of the circular RNAs circ_0002301 and circ_0001955 in breast cancer patients

Several lines of evidence strongly suggest that circular RNAs (circRNAs), a novel class of single-stranded covalently closed non-coding RNAs, are implicated in the etiology of a variety of human diseases, including cancer. We aimed to quantify the expression levels of circ_0002301 and circ_0001955 in breast tumor and normal tissues adjacent to the tumor (NAT).

Breast tumor and paired NAT samples were freshly collected following surgery from fifty women diagnosed with breast cancer. After total RNA extraction, the expression levels of circ_0002301 and circ_0001955 were assessed using quantitative real-time polymerase chain reaction (qPCR) technique. The correlation between circ_0002301 and circ_0001955 expression levels and clinicopathological features evaluated using Spearman's correlation coefficient. Receiver operating characteristic (ROC) curve was drawn to determine the diagnostic values of the studied circRNAs.

We found that circ_0002301 expression level was significantly up-regulated in breast tumor compared to NAT (fold change = 3.39, P = 0.0001). The expression level of circ_0001955 in breast tumor was significantly higher than that in NAT(FC = 2.214, P = 0.009). No significant correlation was between the expression levels of circ_0002301 and circ_0001955 in breast tumor (r = 0.269, P = 0.059). The ROC analysis revealed that the area under the curve (AUC) values of circ_0002301 and circ_0001955 were 0.660 and 0.650, respectively.

The present study provides evidence that up-regulation of circ_0002301 and circ_0001955 may be associated with breast cancer tissues.