OBJECTIVESTo analyze the long-term survivors of glioblastoma and to identify any prognostic factors that potentially contribute to survival.

METHODSFifteen glioblastomas patients underwent surgery from June 2007 to April 2009 who survived longer than 3 years were enrolled in. Clinical characteristics such as age, location of tumor, extent of resection, and radiotherapy or chemotherapy were analyzed. The expressions of epidermal growth factor receptor (EGFR), tumor protein 53 (P53), phosphatase and tensin homolog (PTEN), O6-methylguanine-DNA methyltransferase (MGMT), isocitrate dehydrogenase 1 gene (IDH1), and neurofibromatosis type 1 (NF-1) in tumor samples were measured by immunohistochemical method, and the status of P53 and IDH1 were detected by direct DNA sequencing as well. And the patients who survived less than 1 year were set as control. Kaplan-Meier analysis was used to evaluate the prognostic factors.

RESULTSThe average age of patients at diagnosis was 45.6 years. And the overall survival time was 3-6 years (median survival time 3.5 years). Thirteen patients underwent a total resection, and 14 patients took orally temozolomide. The occurrence frequency of these molecular markers in long-term survivors was PTEN (13/15), IDH1 (13/15), IDH1 mutation (12/15), P53 (8/15), P53 mutation (7/15), EGFR (6/15), MGMT (4/15) and NF-1 (3/15). There was a good correlation between IDH1 protein expression and IDHI mutation, and between P53 protein expression and P53 mutation. And the survival analysis showed that age above 50 years at diagnosis (OR = 0.262, 95%CI: 0.102 - 0.672), total resection (OR = 0.372, 95%CI: 0.149 - 0.931) and combined oral temozolomide (OR = 0.131, 95%CI: 0.044 - 0.390) were favorable clinical prognostic factors. PTEN (OR = 0.201, 95%CI: 0.074 - 0.549) and IDH1 (OR = 0.151, 95%CI: 0.050 - 0.454) expression, IDH1 mutation (OR = 0.276, 95%CI: 0.108 - 0.709) in tumor cells contributed to a favorable prognosis.

CONCLUSIONSThere is probably no single molecular marker that is responsible for long-term survival of patients with glioblastoma, may be a balance between all these molecular events result in a favorable outcome.