Gliomas were assigned to one of the three molecular groups: Group O (IDH-mutant, 1p/19q co-deleted oligodendrogliomas, n = 95), Group A (IDH-mutant, ATRX inactivated astrocytomas, n = 175) and Group G (IDH wild-type, GBM-like, n = 46).
The effect of allergy on survival was significant (p = 0.025, HR 0.525, 95% CI 0.299-0.924), independent of the effect of chromosome 1p (p < 0.001, HR 93.4, 95% CI 16-546) and 19q (p = 0.801, HR 1.2, 95% CI 0.23-6.9) codeletion or TP53 mutation (p = 0.015, HR 2.7, 95% CI 1.2-5.9), unrelated to TERT expression (p = 0.365, HR 1.1, 95% CI 0.89-1.4) or ATRX mutation (p = 0.904, HR 1.04, 95% CI 0.51-2.14), independent of tumor grade (grade 2 versus grade 3, p = 0.004, HR 2.2, 95% CI 1.3-3.8), not independent of histology (oligodendroglioma and oligoastrocytoma, NOS versus astrocytoma, p = 0.08, HR 0.62, 95% CI 0.36-1.1).
LGGs are further divided into isocitrate dehydrogenase (IDH) wild type or mutant, which is further classified into either oligodendroglioma that harbors 1p/19q codeletion or diffuse astrocytoma that has an intact 1p/19q loci but enriched for ATRX loss and TP53 mutation.
Higher frequency of ATRX immune-negativity was detected in grade II/III astrocytic, oligoastrocytic tumors and secondary glioblastomas (GBMs), while infrequent in primary GBMs and rare in oligodendrogliomas.
We analyzed markers, including IDH mutation(IDHmut), 1p19q codeletion(1p19qcodel), ATRX expression loss(ATRX loss) and p53 overexpression, and outcomes in 159 patients with WHO grade II oligodendroglioma, oligoastrocytoma, and astrocytoma (2003-2012).
We found that oligoastrocytomas harbored mutations in TP53 (80%, 12/15) and ATRX (60%, 9/15) at frequencies similar to pure astrocytic tumors, suggesting that oligoastrocytomas and astrocytomas may represent a single genetic or biological entity. p53 protein expression correlated with mutation status and showed significant increases in astrocytomas and oligoastrocytomas compared to oligodendrogliomas, a finding that also may facilitate accurate classification.