INTERPHASE CYTOGENETIC (IN-SITU HYBRIDIZATION) ANALYSIS OF ASTROCYTOMAS USING ARCHIVAL, FORMALIN-FIXED, PARAFFIN-EMBEDDED TISSUE AND NONFLUORESCENT LIGHT-MICROSCOPY

Astrocytomas contain nonrandom chromosomal abnormalities that recently have been correlated with shortened patient survival. Two frequently reported aberrations are trisomy 7 and monosomy 10. We assessed the nu merical complement of chromosomes 7 and 10 in formalin-fixed, paraffin -embedded brain biopsy tissue from 28 diffuse astrocytomas by in situ hybridization using a nonfluorescent enzymatic detection system. Clini cal follow-up of at least 5 years was available in 26 cases (93%). Mon osomy 10 was identified in 7 cases (25%): astrocytoma, 1 case; anaplas tic astrocytoma, 1 case; and glioblastoma, 5 cases. Trisomy 7 was iden tified in 11 cases (39%): astrocytoma, 5 cases; glioblastoma, 6 cases. Multivariate analysis revealed that monosomy 10 was the most statisti cally significant negative predictor of patient survival. Numerical ch romosomal abnormalities ale detectable in astrocytomas in archival tis sue using interphase cytogenetics and nonfluorescent light microscopy. Although larger studies are required, our data suggest that potential ly useful prognostic information may be obtained with this approach.