Fig. 1. Identification of SIRT1 as a prognostic factor in brain cancer.

a Cytogenetics risk category is the single most important prognostic factor in brain cancer. b One hundred and eighty-three brain cancer patients, from the TCGA data set, were clustered into three groups according to cytogenetics risk category (favorable: N = 40; Normal: N = 103; Poor: N = 40). c Patients were clustered into two groups according to the expression levels of SIRT1 (low-SIRT1 expression group: N = 36; high-SIRT1 expression group: N = 147). d Kaplan–Meier analysis reveals a positive correlation between patient overall survival rates and SIRT1 mRNA expression levels. e Representative immunoreactivity intensities of SIRT1 for negative (0), weakly positive (1), positive (2), strongly positive (3) staining. Scale bar = 50 μm. The expression of SIRT1 is downregulated in glioblastoma tissues (P < 0.0001) compared with normal brain tissues