Abstract: Objective To examine the expression level of miR-24 in the plasma of nasopharyngeal carcinoma (NPC) patients and
investigate the clinical significance of miR-24 in NPC development. Methods Blood samples were from 217 NPC patients
admitted in our Department between December, 2007 and June, 2011, with those from 73 patients with chronic purulent otitis
media or chronic sinusitis as control. The follow-up data of all the patients were reviewed and the expression of miR-24 in the
plasma was examined by qRT-PCR. The correlation of miR-24 expression with clinical staging of NPC was analyzed, and
miR-24 levels before and after the treatment were compared. Results Compared with the control group, the NPC patients
showed significantly up-regulated level of miR-24 in the plasma (P<0.001). Plasma miR-24 level differed significantly among
patients with different T stages (P=0.007) and was negatively correlated with the N stages (P=0.028) and plasma EBV-DNA (P=
0.048). The expression levels of miR-24 were significantly reduced after treatment in the NPC patients and were significantly
lowered in patients without relapse or metastasis (P=0.001). Conclusion Plasma miR-24 may serve as a novel molecular
biomarker for early diagnosis and prognosis of NPC.