Objectives: This study was conducted to investigate the clinical significance of Slit2 and Robo1 expression in prognosis of patients with brain gliomas.Methods: Human brain tissue samples were collected from normal glial tissues (control), low-and high-grade glioma tissues. Slit2 and Robo1 expression levels in cells were assessed by an immunohistochemistry (IHC), and population of the Slit2- and Robo1-presenting patients was examined. The Slit2 and Robo1 mRNA expression levels in three types of the brain cells was determined by RT-PCR.Results: Slit2(+) cell counts were decreased with increased Robo1(+) cells in the low-grade and high-grade glioma tissues as compared to the control. The percentage of cells expressing Slit2 decreased from the control to the high-grade glioma and the percentage of cells expressing Robo1 in low-and high-grade gliomas was increased as compared to the control (P < 0.01). The decrease in the Slit2 mRNA expression was associated with the increase in the Robo1 mRNA expression in the low-and high-grade gliomas (P < 0.01 or 0.05). Survival time for patients with Slit2(-)/Robo1(+) gliomas was shorter than patients with Slit2(+)/Robo1(+) gliomas in the investigated cohorts (P < 0.01).Conclusion: Slit2 and Robo1 expression levels serve as a biomarker with utility in grading gliomas as well as predicting patient survival. The change in Slit2 expression is more reliable and effective than Robo1 expression in predicting a poor prognosis of brain glioma patients. (C) 2016 Published by Elsevier Ltd.