MiR-21 level is markedly elevated in human GBM tumor tissues [11–13]. It targets multiple components and plays an anti-apoptotic function in GBM. We found that miR-21 is significant higher in plasma of GBM patients than in controls, which is

consistent with the finding of miR-21 with significant levels in CSF sample and tissue from EX 527 order patients with glioma [9, 11]. Furthermore, although circulating miR-21 is reduced in postoperation compared to preoperation, no significant difference existed. MiR-21 is observably decreased after further treatment with chemo-radiaton. Thus, these data suggest a possible association between miR-21 and treatment effect. The expression level of brain-enriched miRNA-128 in glioma tissues is inversely correlated with tumor grade and function as a tumor suppressor [17]. Similarly, we found that expression level LCZ696 manufacturer of miR-128 in plasma of GBM patients was also decreased and negatively

relevant to high and low grade glioma, just same as the tendency reflected in the test results of glioma tissues. But another research reported that miR-128 was up-regulated in peripheral blood of GBM patients [10]. The reason may be that miRNAs contained blood cells cause the difference. Our data also revealed that miR-128 is up-regulated after glioma patients were treated, so miR-128 may be associated with curative effect. To date, little is known whether miR-342-3p is dysregulated in glioma tissues and has an effect on glioma development. Roth et al. reported that miR-342-3p was down-regulated in peripheral blood of GBM patients [10]. In the present study, our results also showed that the expression level of miR-342-3p is reduced in the plasma of glioma patients and also inversely correlated with glioma grade. In addition, we assessed the expression of miR-342-3p by real-time PCR in the group of patients who had been treated by operation and chemo-radiation. miR-342-3p is significantly increased

and there are no differences between ASK1 normal, control plasma and plasma sampling received therapies. All these results reveal that plasma-derived miR-342-3p may be a suitable biomarker which can function as diagnosis, classification and therapeutic effect. The mechanism of origin of extracellular miRNAs remains to be fully elucidated. Some researchers have demonstrated that miRNAs in plasma are released from cells in membrane-bound vesicles which are named microvesicles (exosomes). These exosomes come from multivesicular bodies and are released by exocytosis and also can be shed by outward budding of the plasma membrane [18–21]. These early reports are confirmed by which cultured cells release exosomes containing miRNAs [22–24]. Similarly, one study has also demonstrated that microvesicles (exosomes) containing miRNAs are released from glioblastoma cells and the size of them is from 50 to 500 nm [25].