P53 GENE MUTATION IN CEREBRAL PRIMITIVE NEUROECTODERMAL TUMOR IN TAIWAN

p53 mutation has been rarely reported in cerebral primitive neuroectod ermal tumors (PNET). To determine the significance of p53 mutations in the development of cerebral PNET, we studied cerebral PNET samples fr om 14 patients, 8 females and 6 males with a mean age of 38 years (ran ge 10 months to 77 years) who had total or subtotal surgical resection . Histological typing of PNET with neuronal (N) and non-neuronal (NN) differentiation groups revealed 8 and 6 cases, respectively. Six (43%) of the 14 patients had p53 mutation. The p53(+) and p53(-) groups had an age range of 19-77 with a mean of 49 years and 10 months to 57 yea rs with a mean of 30 years, respectively. p53 expression between the P NET-N and PNET-NN groups was 5 of 8 (62.5%) and 1 of 6 (16.7%), respec tively. The mutations contained 3 transitions, 2 transversions and 1 f rameshift; none of them occurred at the site of 'hot-spot' residues (c odons 175, 248, 273). The results suggest that: (1) p53 mutation in ce rebral PNET tends to show a higher incidence of neuronal differentiati on and occurs in the older age group in Taiwan, (2) there was no diffe rence in survival time between the PNET-N and PNET-NN groups (7 months and 6 months) (P = 0.54), and between p53(+) and p53(-) groups (6 mon ths and 7 months) (P = 0.57), and (3) PNET may be an entity of a heter ogenous group of tumors with different genetic mechanisms controlling their trends of differential lineage. Further studies are needed to de termine the significance of p53 mutations in PNET development, especia lly the role of carcinogens in the genesis of PNET in Taiwan.