Background: Mir-9 was recognized as a potential tumor suppressor gene or oncogene in varies of diseases; however, its roles in glioma have not been investigated. Our study was to identify the mRNA expression of mir-9 gene in glioma and correlate abnormal versions of microRNAs with clinicopathological features and investigate the impact of mir-9 in glioma prognosis.
Methods: Seventy-one glioma samples, which included 22 grade II, 24 grade III, and 25 glioblastoma tumors of previously untreated patients who underwent surgical excision at Qing Hai Province People’s Hospital from 2011 to 2014, were included. In addition, 2 epilepsy patients with normal brain tissue were included as a control group. The expression of mir-9 was examined by RT-PCR in formalin-fixed paraffin embedded primary tissue specimens. The clinicopathologic features, the survival rate of glioma patients were also discussed. The RNA expression of mir-9 and glioma prognosis was evaluated using a Chi-square test, Cox regression model, and GraphPad Prism survival curve analysis.
Results: There were 16, 20, 21 cases which showed high expression of mir-9 in grade II and III gliomas and glio-blastoma, 16/22 (72.7%), 20/24 (83.3%), 21/25 (84.0%), respectively. The expression of mir-9 was correlated with the grade of glioma. The mir-9 RNA expression in glioblastoma were higher than grade II and III gliomas (p < 0.05). The higher the grade, the higher the expression, and the difference was significant (p < 0.05), while it was not correlated with patient nationality, gender, or location (p > 0.05). Univariate analysis determined that high expression of mir-9, grade, chemotherapy, radiation therapy, and patient onset age were associated with glioma patient prognosis (p < 0.05).
Conclusions: The expression of mir-9 plays a role in glioma progression, and may be used as a prognostic marker in glioma.