Given the higher prevalence of cysts in lower grade tumors, there have been a number of studies looking for a mechanism behind the improved prognosis of patients with cystic GBM, including notable molecular compounds present in cystic GBM fluid, histopathological differences between cystic and noncystic GBM and prevalence of IDH1 mutants in cystic GBM (11, 12). Here, IDH1 is linked to glioblastoma.