Intratumorous heterogeneity of chromosome 10 and 17 in meningiomas using non-radioactive in situ hybridization.

Contrary to classical cytogenetics non-radioactive chromosomal in situ hybridization (CISH) may be performed within 24 hours while the morphological structure of paraffin-embedded tumor material is preserved. Slides of 34 formalin fixed and paraffin-embedded meningiomas were hybridized with a biotinylate alpha-satellite DNA-probe for chromosome 10 and 17. According to the distribution of hybridization signals per nucleus we found five meningiomas with signs of trisomy 17 whereby all of them exhibited intratumorous heterogeneity. Trisomy 10 was found in five tumors. Monosomy 17 was assumed in two cases and monosomy 10 in one meningioma. As a control six meningiomas were karyotyped by G-banding. Formalin fixed and paraffin-embedded tissue of the same tumors was hybridized against chromosome X and Y. In five of six cases the result of conventional karyotyping could be confirmed by in situ hybridization. CISH of paraffin-embedded tissue is new tool for the analysis of intratumorous cytogenetical heterogeneity with potential prognostic significance.