Selective expression of a subset of neuronal genes in oligodendroglioma with chromosome 1p loss.

Gliomas are classified based mainly on microscopic resemblance to their presumed glial origin such as astrocyte and oligodendrocyte. However, more objective diagnostic criteria are indispensable for the precise treatment of patients. For instance, loss of the short arm of chromosome 1 (1p) in oligodendrogliomas is recognized as an important marker for better response to chemotherapy and longer survival of the patients. To gain insight into their molecular biological background and to identify genes characterizing each subgroup, we investigated gene expression profile of the 4 glioma subsets, oligodendroglioma with and without 1p loss, diffuse astrocytoma and glioblastoma using DNA microarray. Remarkably, most of the genes showing distinctive expression in oligodendroglioma with 1p loss were also highly expressed in normal brain tissues and had neuron-related function, which included MYT1L, INA, RIMS2, SNAP97 and SNCB. Histological analysis also demonstrated that MYT1L, which were abundantly expressed in normal neuron, were certainly present in tumor cells. These results suggest that oligodendroglioma, especially with 1p loss, has more or less neuronal characteristics although oligodendroglioma is thought to originate form glial lineage cell. With further pathological studies, those neuron-related genes might be good diagnostic markers for oligodendroglioma of better prognosis as well.