It is well known that the BM microenvironment is vital to the oncogenic growth of MM cells, and many studies have been conducted to explore the impact of circular RNAs on the BM microenvironment through intercellular communication.12 CircRNAs are enriched and stable in exosomes that may serve as potential biomarkers for cancer detection and transfer biological activity to recipient cells.22 We extracted the exosomes from the culture supernatant of CAG and H929 cells, which were identified by TEM method (Fig. 5i) and WB analysis for two markers Alix and CD9 (Fig. 5j). Here, CD9 is linked to cancer.