SIX3 and glioblastoma: In this study, using the results from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA), we analyzed the level of methylation on the CpG island of SIX3 promoter and confirmed our earlier findings that SIX3 is hypermethylated in both low-grade glioma and glioblastoma (Fig. 1a, S1A).