Differential expression of MicroRNAs in patients with glioblastoma after concomitant chemoradiotherapy

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor, and notorious for resistance to chemoradiotherapy. MicroRNAs (miRNAs) are significantly involved in the initiation and progression of numerous cancers; however, the role of miRNAs in recurrence of tumors remains unknown. Here we tried to identify novel miRNAs that are differentially expressed in recurrent GBM. Tissue samples were obtained from patients with primary and recurrent GBM treated with chemoradiotherapy, and the expression changes of miRNAs were measured by microarray. A total of 318 miRNAs were expressed in the GBM patients. The expression of 43 miRNAs were significantly altered at least 2-fold in primary and recurrent GBMs. Bioinformatic analysis revealed that the differentially expressed miRNAs and their putative target genes were mainly involved in cell death, cellular development, and cellular growth and proliferation, which are the key regulators for stem cells. Pathway analysis supported that the miRNAs may regulate signaling associated with induction and maintenance of cancer and stem cell, such as p53, ErbB1, Notch, Wnt, and TGF-β signaling pathways. These data suggest that, in recurrent GBM, growth factor and anti-apoptotic signalings for cancer cell growth and proliferation are regulated by miRNAs. Our findings will aid future research in understanding the pathophysiology of recurrent GBM and identifying diagnostic markers and/or therapeutic targets for recurrence of GBM.