Background: Recently, miRNA-181a2 could be identified as a major regulator of IDH1
expression in fat tissue. The IDH1 gene, its mutation and expression have a major impact on overall
survival in patients with glioblastoma. The presented study aimed to investigate the effect of miRNA181a2 on IDH1 expression in glioblastoma and on the prognosis of patients suffering from, for
example, a tumor. Methods: A total of 74 glioblastoma specimens were analyzed for the expression
of miRNA-181a2, acquired as fold change, using qRT-PCR. IDH1 protein expression was estimated
via mRNA quantification. Eight post mortal, non-glioma related brain tissue specimens served as
the control group. The results were correlated with relevant demographic and clinical aspects of
the cohort. A TCGA dataset was used as an independent reference. Results: MiRNA-181a2 was
significantly downregulated in tumor samples compared to the control group (p < 0.001). In the
glioblastoma cohort, 63/74 (85.1%) showed an IDH1 wild type, while 11/74 (14.9%) patients harbored
an IDH 1 mutation. In patients with IDH1 wild type glioblastoma, low miRNA-181a2 expression
correlated with a prolonged overall survival (p = 0.019), also verifiable in an independent TCGA
dataset. This correlation could not be identified for patients with an IDH1 mutation. MiRNA-181a2
expression tended to correlate inversely with IDH1 protein expression (p = 0.06). Gross total resection
of the tumor was an independent marker for a prolonged survival (p = 0.03). Conclusion: MiRNA181a2 seems to be a promising prognostic marker of selective glioblastoma patients with IDH1 wild
type characteristics. This effect may be mediated via direct regulation of IDH1 expression