Previous evidence has shown that circRNAs are highly expressed and evolutionarily conserved across the eukaryotic tree of life, thus, indicating potential biological functions.29 Additionally, reports revealed that circRNAs may be involved in the development and progression of cancer.30, 31 First, our study found that a higher CDR1as expression was observed in breast cancer samples; CDR1as may play a role in the development of drug resistance in breast cancer, and a positive correlation was observed between drug resistance and CDR1as expression in breast cancer. This evidence concerns the gene LINC00632 and breast cancer.