ATRX and IDH1-R132H immunohistochemistry with subsequent copy number analysis and IDH sequencing as a basis for an "integrated" diagnostic approach for adult astrocytoma, oligodendroglioma and glioblastoma.
The reported two cases were initially diagnosed as oligodendroglioma with 1p/19q-codeletion and mutation of <i>isocitrate dehydrogenase 1 (IDH1)</i>-R132H.
The histopathological findings of his surgical specimen revealed characteristics of a low-grade glioma with an IDH1 c.395G>A (R132H) mutation and 1p/19q codeletion, which led to a definitive diagnosis of oligodendroglioma.
The mutation analysis performed on the latter case with DNA separately sampled from the oligodendroglioma- like area and the astrocytoma-like area detected IDH1 G395A in both areas.
Three GBM-O samples had IDH1 (p.R132H) mutations; two of these also demonstrated 1p/19q co-deletion and had a proneural transcriptional profile, a molecular signature characteristic of oligodendroglioma.
We evaluated nuclear cMYC protein levels and IDH1 (R132H) by immunohistochemistry in patients with oligodendroglioma/oligoastrocytomas (n = 20), astrocytomas (grade II) (n = 19), anaplastic astrocytomas (n = 21) or glioblastomas (n = 111).