Circular RNA expression in exosomes derived from breast cancer cells and patients.

Aim: We aimed to explore the roles of circular RNAs (circRNAs) in breast cancer (BCa). Materials & methods: RNA was extracted from exosomes and BCa cells and analyzed using the RNA sequencing technique or microarray. Results: Compared with controls, 1147 and 1195 circRNAs were dysregulated in exosomes from metastatic and localized BCa patients, respectively. A total of 480 dysregulated circRNAs were found in metastatic patients compared with localized patients, and these dysregulated circRNAs were enriched in eight pathways. Compared with MCF-7 cells and their exosomes, there were 5842 and 1137 dysregulated circRNAs in MDA-MB-231 cells and exosomes, respectively, and 5 circRNAs were confirmed using real-time quantitative PCR. Conclusion: We identified a number of dysregulated circRNAs in exosomes from BCa cells and patients.