2nd Workshop Neurogenetics in Germany, Munich, October 19-21, 1995
The glioblastoma (gbm) of 22 pediatric patients operated on at a single center between 1975 and 1992 (age range 0-18, median age 10.9) were analyzed for mutations in the evolutionary conserved areas (exons 5-8) of the p53 tumor suppressor gene using single-strand conformation analysis (SSCA) and direct sequencing. In contrast to adult gbm more than half of the pediatric tumors were located outside the cerebral hemispheres (12/22). Seven glioblastomas arose in the brainstem, three in the thalamus, one in the cerebellum and one in the spinal cord. Mutations were detected in three hemispheric tumors, in two brainstem tumors and in the spinal gbm. Three tumors exhibited a point mutation, one was detected in codon 204 (GAG->TAG) of exon 6, one was located in codon 238 (TGT->TCT) of exon 7 and the third was detected in codon 273 (CTG>TGT) of exon 8. Deletions and insertions are rare alterations of the p53 gene. Interestingly, a tandem repeat of codons 215-217 was observed in one tumor, a deletion of codon 236 in a second and a deletion of codons 177-182 in a third gbm. Mutations could be detected in pediatric gbms of all locations, including the spinal cord and brain stem.
Pediatric gbms in our study exhibited a similar mutation frequency (6/22) as reported from adult gbms ranging from 23 to 55%, suggesting that pediatric and adult gbms might share underlying genetic mechanisms in tumorigenesis despite their different pattern in location. Of further interest are the insertions and deletions in our patients, however, numbers are to small to argue that such alterations might be commonly associated with the younger age of the patients.
p53 gene mutation frequency