OBJECTIVETo investigate the relationship between the expression level of microRNA 92a (miR-92a) and del(13q14) and the prognosis of MM patients, and to explore the pathway that miR-92a involved.

METHODSBone marrow samples from 53 newly diagnosed MM patients were collected, del(13q14) was analyzed by interphase fluorescence in situ hybridization in sorted CD138 positive plasma cell. The expression of miR-92a in plasma cells was measured by quantitative real-time PCR. The expression of c-jun was detected by Western blot in miR-92a transfected MM cell lines (LP-1, U266 and JJN3).

RESULTSOf the 53 MM patients, del(13q14) was detected in 31 (58.4%) patients. The median levels of miR-92a in MM patients with or without del(13q14) were 27.36±2.61 and 21.87±15.98, respectively (P>0.05). With the median follow-up of 13.5 (0.5-72.5) months, the median duration of progression-free survival of patients with high expression level of miR-92a was significantly shorter than those with low expression level of miR-92a (4.5 months vs 14.0 months, P=0.006). Overexpression of miR-92a in MM cell lines induces time-dependent down-regulation of c-jun.

CONCLUSIONSHigh expression of miR-92a was associated with poor prognosis in MM patients. The expression level of miR-92a was not associated with del(13q14), and the effect of miR-92a on the progress of MM might be involved in c-jun pathway.