Development and validation of a prognostic gene expression signature for lower-grade glioma following surgery and adjuvant radiotherapy

•The timing and benefit of adjuvant radiation for lower-grade glioma (WHO grade II–III) are not well established.•A prognostic signature constructed from the expression of 5 genes was validated in patients with lower-grade glioma in two unrelated genomics consortia.•This signature was significantly associated with progression-free survival and overall survival, independent of relevant covariates, and may also be predictive of response to radiation treatment.