Objective: To project a new molecular classification system for anaplastic gliomas based on the molecular biomarkers.
Methods: There were 161 patients with histological diagnosis of primary anaplastic gliomas after operation and complete and reliable follow-up data were enrolled in the study from May 2009 to June 2011. A total of 100 male and 61 female patients with a median age of (43 ± 12) years (range: 17-68 years). After the pathology review by 2 experienced neuro-pathologists, 36 anaplastic oligodendroglioma (AO), 66 anaplastic oligoastrocytoma (AOA) and 59 anaplastic astrocytoma (AA) were confirmed. There were 116 patients underwent gross-total resection, 37 sub-total resection and 8 partial resection. Molecular biomarkers evaluated included 1p/19q, IDH1 gene and O6-methylguanine-DNA-methyltransferase (MGMT). Kaplan-Meier plots were compared by Log-rank method.
Results: The survival analysis results showed that the 6-month, 12-month, 18-month and 24-month progression-free survival (PFS) and overall survival (OS) rates of AO was significantly longer than AOA(χ(2) = 12.812 and 6.557, P < 0.05) and AA (χ(2) = 19.125 and 10.206, P < 0.05), but no significant difference of prognosis was observed between AOA and AA (P > 0.05). According to the status of biomarkers, AOA was reclassified into two subgroups-AOA1 and AOA2. AOA1 with 1p/19q co-deletion, IDH1 mutation and/or negative MGMT expression showed similar prognosis with AO (P > 0.05). AOA2 without any biomarkers showed similar prognosis with AA (P > 0.05). Besides, the 6-month, 12-month, 18-month and 24-month PFS and OS rates of patients with AO and AOA1 was significantly longer than patients with AA and AOA2 (PFS:χ(2) = 25.180, P < 0.001; OS: χ(2) = 15.649, P < 0.001). Multivariate analysis showed that the moecular pathology subtypes classified was an independent prognostic factor (PFS: OR = 0.499, 95% CI:0.381-0.653, P < 0.001; OS:OR = 0.605, 95% CI:0.450-0.814, P = 0.001).
Conclusions: The molecular classification system for anaplastic gliomas will be helpful in estimating patients' prognosis and guiding reasonable therapy for patients with anaplastic gliomas.