GENOMIC STABILITY AND WILD-TYPE P53 FUNCTION OF LYMPHOBLASTOID-CELLS WITH GERM-LINE P53 MUTATION

Increased cancer risk associated with germ-line p53 mutation was linke d to a deficit in the ability to maintain genomic stability. According ly, normal fibroblasts from cancer-prone individuals accumulate genomi c aberrations with concomitant loss of mild-type p53 allele during in vitro culture. We tested whether such changes also occur in EBV-immort alized lymphoblastoid cells. Both normal and p53 germ-line mutant lymp hoblastoid cells maintained functional p53 and genomic stability durin g long term ill vitro culture. These unexpected differences between fi broblastic and lymphoblastic cells suggest that phenotypic expression of p53 deficiency is cell type specific. This could contribute to sele ctive tissular localization of tumours observed in patients with Li-Fr aumeni syndrome despite the presence of a mutant p53 allele in all cel ls.