S. Alsarraj et al., P53 ALLELIC IMBALANCE IN ASTROCYTOMA DETECTED USING FLUORESCENT PCR OF MICROSATELLITE REPEAT POLYMORPHISMS, Neuropathology and applied neurobiology, 21(4), 1995, pp. 344-351
Previous reports have shown that p53 gene alteration plays an importan
t role in tumourigenesis. Allelic loss of 17p in astrocytomas was dete
cted in previous studies by restriction fragment length polymorphisms
(RFLP). In this study we have analysed 47 cases of astrocytic tumours
(26 glioblastomas [grade IV], 11 anaplastic astrocytomas [grade III],
seven fibrillary astroctyomas [grade III] and three pilocytic astrocyt
omas [grade I]) for the presence of allelic imbalance at the p53 gene
locus using intragenic markers. We used an informative method based on
microsatellite polymorphisms at the p53 gene locus and fluorescent PC
R. The fluorescently-labelled PCR products were then detected and anal
ysed using an automated DNA sequencer with appropriate software. Seven
of 47 (14.9%) cases were homozygous (uninformative). Five of the rema
ining 40 cases (12.5%) showed allelic imbalance at the p53 locus (thre
e anaplastic astrocytomas [grade III] and two glioblastomas [grade IV]
). None of the fibrillary astrocytomas (grade II) or pilocytic astrocy
tomas (grade I) showed allelic imbalance at the p53 locus. These resul
ts suggest that allelic imbalance at the p53 locus is not frequent and
when it does occur is in high grade tumours.