Oligodendrocyte lineage genes (OLIG) as molecular markers for human glial brain tumors

The most common primary tumors of the human brain are thought to be of glia l cell origin. However, glial cell neoplasms cannot be fully classified by cellular morphology or with conventional markers for astrocytes, oligodendr ocytes, or their progenitors. Recent insights into central nervous system t umorigenesis suggest that novel molecular markers might be found among fact ors that have roles in glial development. Oligodendrocyte lineage genes (Ol ig1/2)encode basic helix-loop-helix transcription factors. In the rodent ce ntral nervous system, they are expressed exclusively in oligodendrocytes an d oligodendrocyte progenitors, and Olig1 can promote formation of an chondr oitin sulfate proteoglycon-positive glial progenitor. Here we show that hum an OLIG genes are expressed strongly in oligodendroglioma, contrasting abse nt or low expression in astrocytoma. Our data provide evidence that neoplas tic cells of oligodendroglioma resemble oligodendrocytes or their progenito r cells and may derive from cells of this lineage. They further suggest the diagnostic potential of OLIG markers to augment identification of oligoden droglial tumors.