Four normal brain tissues, ten primary LGG and ten HGG samples were obtained from Department of Neurosurgery, the First Affiliated Hospital of Nanjing Medical University (Nanjing, China). The clinic pathological and general information of those patients are shown in Supplementary Table 1. Written informed consent was obtained from all patients. Our study was approved by the Institutional Review Board and the ethics committee of Nanjing Medical University and Harbin Medical University.