Tumor cells of a particular tissue may show a pattern of gene expression characteristic of the precursor cells of this tissue. To test this proposition for tumors of the central nervous system (CNS) we have used immunohistochemistry to analyze the expression of nestin in primary human CNS tumors and corresponding nonneoplastic brain tissue. Nestin defines a recently discovered sixth class of intermediate filament proteins and in the rat is expressed predominantly in CNS stem cells. In the adult nonneoplastic human brain we have detected only nestin expression in occasional endothelial cells. In contrast, a variety of primary CNS tumors contained substantially elevated nestin levels. The nestin-positive cells in the tumor tissue were tumor cells and/or endothelial cells. Glioblastomas expressed higher nestin levels than less malignant gliomas. This may indicate a correlation between nestin expression and malignancy within the glioma tumor group. In the primitive neuroectodermal class of tumors we observed both nestin-expressing and nonexpressing tumors, suggesting that nestin expression could be used to further characterize this complex and heterogeneous tumor group. Nine metastatic carcinomas were studied, and none showed nestin immunoreactivity in tumor cells. In conclusion, our data support the notion that primary CNS tumors share gene expression patterns with primitive, undifferentiated CNS cells and that nestin, like other intermediate filaments, may be useful in tumor diagnosis.
This work was made possible by grants from the Swedish Cancer Society, the Swedish Medical Research Council, Margaret och Axel Axôn Johnsons Stiftelse, Knut and Alice Wallenbergs Stiftelse, Magn. Bergvalls Stiftelse, Stiftelsen Lars Hiertas Minne, Karolinska institutets fonder (J. D. and U. L.), and the Stockholm Cancer Society.