The expression of complement regulatory proteins (CRP) on the surface of neoplastic cells has been proposed as a mechanism by which these cells evade immune surveillance. We have examined the RNA expression of the genes that encode 5 kinds of CRP in various human brain tumors to determine whether CRP expression might play a role in the malignant progression of these tumors. The benign and atypical meningiomas, and the astrocytomas showed high expression of SP-40,40, low expression of CD59, and barely detectable expression of CD46, CD55 and S-protein. The benign and atypical menigiomas showed significantly greater expression of SP-40,40 at the RNA level when compared to malignant meningiomas. This study describes the mRNA expression of meningiomas, astrocytomas, tumor cell lines and normal human tissues.