Identification of MM-BMSC–specific EV miRNAs. (A) Representative transmission electron micrographs of EVs derived from normal-BMSCs and MM-BMSCs. Scale bar, 50 nm. Nanoparticle concentrations and size distributions of EVs derived from normal-BMSCs (blue line) and MM-BMSCs (red line). An average of 2.1 × 105 and 2.0 × 105 EVs were recovered from 1 mL of culture supernatant of normal-BMSCs and MM-BMSCs, respectively. (B) Western blotting for CD63, CD81, and TSG101 in EVs derived from BMSCs. (C) Differential miRNA expression levels in normal-BMSC–EVs (n = 2) and MM-BMSC–EVs (n = 6) as a screening cohort. (D-F) EV and cellular miRNA (miR-10a, miR-346, and miR-135b) expression levels in normal-BMSCs (n = 2) and MM-BMSCs (n = 6) by quantitative polymerase chain reaction array. Box plot whiskers represent minimum and maximum values. P values were calculated by using independent-sample Student t tests. *P < .01.