Ras p21 expression in brain tumors: elevated expression in malignant astrocytomas and glioblastomas multiforme.

We have employed an immunohistochemical analysis to study the ras p21 oncoprotein in a total of 41 brain tumors and 1 reactive gliosis. The tumors included 33 astrocytomas, 1 oligodendroglioma, 2 ependymomas, 1 neurilemmoma, 1 malignant meningioma, 1 neuroblastoma and 2 medulloblastomas. Our results indicate that elevated ras p21 expression is a common feature in a range of brain tumors. In particular, elevated ras p21 expression has been found in 18 out of 24 high grade astrocytomas (malignant astrocytomas and glioblastomas multiforme) compared to 3 out of 9 low grade (well differentiated astrocytomas) (P less than 0.05). These results suggest that ras p21 expression may be an important molecular marker of the malignant astrocytomas and glioblastomas multiforme.