Recurrent gain of chromosome arm 7q in low-grade astrocytic tumors studied by comparative genomic hybridization.
Consistent tumor-specific chromosomal aberrations have not been described in low-grade astrocytic tumors. The most frequent genetic alterations are mutations of the TP53 tumor suppressor gene and/or loss of heterozygosity (LOH) on 17p that occur in about 30% of the cases in adult patients but that are uncommon in childhood tumors. We used comparative genomic hybridization (CGH) to map DNA copy number alterations in 18 primary low-grade astrocytic tumors (ten adult patients and eight children). A gain of chromosome arm 7q was the most frequent event detected in five of ten astrocytomas (50%) from adult patients, followed by DNA amplification on chromosome arm 8q and gain on 12p (two cases). Loss of chromosomal regions on 1p, 4q, and the X chromosome was observed in two of ten cases [including one patient afflicted with Turner syndrome (45,X)]. In contrast, no consistent changes were observed in low-grade astrocytomas in children. A loss of the X chromosome was the sole aberration detected in two of eight cases using DNA extracted from the normal brain tissue. The findings suggest that a gain of 7q is an early event in the initiation of astrocytomas in adult patients. The discrepant findings in low-grade astrocytic tumors in adults compared to tumors in children support the the hypothesis that there might be different mechanisms responsible for tumor development.
Schröck
E
E
Institute of Human Genetics, University of Heidelberg, Germany.
Blume
C
C
Meffert
M C
MC
du Manoir
S
S
Bersch
W
W
Kiessling
M
M
Lozanowa
T
T
Thiel
G
G
Witkowski
R
R
Ried
T
T
Cremer
T
T
D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000235:genetics*; D001932:Brain Neoplasms / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D002897:Chromosomes, Human, Pair 7; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization