Accumulation of allelic losses on chromosome 10 in human gliomas at recurrence

Chromosomal aberrations detected by comparative genomic hybridization (CGH) in human astrocytic tumors

We investigated chromosomal aberrations in 16 patients with astrocytic tumors of various histologic malignancies by comparative genomic hybridization (CGH). The degree of chromosomal loss was shown to be negatively correlated with histologic malignancy. Losses of portions of chromosomes 1p, 19q and 22q were the three chromosomal aberrations observed most frequently. Alterations in multiple chromosomes were observed more frequently in glioblastomas than in astrocytomas or anaplastic astrocytomas (P < 0.001). Primary glioblastomas showed a high frequency of genomic DNA gains (5/7), whereas recurrent glioblastomas from anaplastic astrocytomas did not (0/3). We found CGH to be a powerful tool for surveying DNA alterations in tumors and characterizing the biology of tumors of astrocytic lineage.

Stochastic determination of the chromosomal region responsible for expression of human glial fibrillary acidic protein in astrocytic tumors

Previous investigators have localized the human glial fibrillary acidic protein (GFAP) gene in the segment 17q21 in chromosome 17. In the present study, we statistically assessed the association between the allelic status in thirty-three microsatellite loci and the immunohistochemical expression of GFAP in twenty human astrocytic tumors. The results demonstrated that the loss of heterozygosity in only one locus (D17S795 located in 17q21.2) was significantly associated with the impaired expression of GFAP (P = 0.0280, Pc = 0.0384 by Fisher's exact test). The adjacent loci located in 17q21.1 and 17q21.3 were not relevant to GFAP expression. Those data suggest that the critical region responsible for GFAP expression (coding sequence and regulatory elements) is located close to the locus D17S795 in the segment 17q21.2.