PRESENCE OF P53 MUTATIONS IN PRIMARY NASOPHARYNGEAL CARCINOMA (NPC) IN NON-ASIANS OF LOS-ANGELES, CALIFORNIA, A LOW-RISK POPULATION FOR NPC

Mutatins of the p53 tumor suppressor gene are rare in nasopharyngeal c arcinoma (IVPC) patients who reside in high-risk areas, such as Southe astern China, Among this high-risk group, a pre-existing infection wit h the EBV and consumption of Cantonese salted fish are closely associa ted with NPC, We investigated the prevalence of p53 mutations in 28 pr imary NPC specimens from white (including Hispanic) and African-Americ an patients in Los Angeles, who are at low risk for NPC, Using PCR-bas ed single-strand conformational polymorphism and direct sequencing, we found four mutations (14%) in exons 5-8 of the p53 gene in four patie nts, All were C-to-T transition mutations: two were present in exon 5- one at codon 142 [C (C) under bar T (Pro) --> C (T) under bar T (Leu)] and another at codon 144 [(C) under bar AG (Gin) --> (T) under bar AG (stop codon)l. The other two mutations were identified in exon 8: one at codon 273 [C (G) under bar T (Arg) --> C (A) under bar T (His)], a CpG site, and one at codon 271, a silent mutation [GA (G) under bar ( Glu) --> GA (A) under bar (Glu)], This is the first report investigati ng the presence of p53 missense mutations in NPC among a low-risk popu lation, Our data indicate that p53 is also an infrequent event among N PC patients at low risk for the disease.