IDENTICAL MUTATIONS OF THE P53 TUMOR-SUPPRESSOR GENE IN THE GLIOMATOUS AND THE SARCOMATOUS COMPONENTS OF GLIOSARCOMAS SUGGEST A COMMON ORIGIN FROM GLIAL-CELLS

Gliosarcomas are morphologically heterogeneous tumors of the central n ervous system composed of gliomatous and sarcomatous components. The h istogenesis of the latter is still a matter of debate. As mutations of the p53 tumor suppressor gene represent an early event in the develop ment of gliomas, we attempted to determine whether both components of gliosarcomas share identical alterations of the p53 gene. Using single -strand conformation analysis (SSCA) and direct DNA sequencing of the p53 gene, we analyzed dissected gliomatous and sarcomatous parts of 12 formalin-fixed, paraffin-embedded gliosarcomas. The two tumors that c ontained a p53 alteration were found to carry the identical mutation ( exon 5; codon 151, CCC --> TCC; codon 173, GTG --> GTA) in the gliomat ous and the sarcomatous components. These findings suggest a common or igin of the two cellular components from neoplastic glial cells.