Analysis of sex chromosomal numerical aberrations in human astrocytomas by FISH

Although sex chromosomal aberrations in astrocytomas have been frequently reported by cytogeneticists, their biologic significance is still unclear. The aim of this study was to investigate sex chromosomal aberrations of astrocytomas by fluorescence in situ hybridization (FISH) and to determine whether there is a relationship between these aberrations and abnormalities of chromosomes 7 and 10. The astrocytoma specimens were obtained from 14 male and 11 female patients. The centromeric probes DYZ1, DXZ1, D7Z1 and D10Z1 were used to determine the numerical changes in chromosomes Y, X, 7, and 10 by FISH. The hybridization spots were counted by fluorescence microscopy. Three cases showed chromosome X aberrations, including two cases with loss of chromosome X and one case with a complex chromosome X aberration among 11 female astrocytomas. Eight cases with loss of chromosome Y were seen among 14 male astrocytomas; one was grade II, three grade III, and four grade IV tumors. One case of disomy X was observed among male grade II tumors. Seven of the eight tumors with loss of chromosome Y had additional complex chromosome aberrations. Our results suggest that sex chromosome aberrations in malignant astrocytomas are non-random and frequent. These changes suggest an association with aberrations of chromosomes 7 and 10. These sex chromosome aberrations seem to be a part of a complex chromosome pattern of aberrations in astrocytomas. The observed abnormalities may not necessarily be a part of the neoplastic progression in malignant astrocytomas, but they may be of biologic significance.