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 carcinoma (NPC) patients who reside in high-risk areas, such as Southeastern China. Among this high-risk group, a pre-existing infection with the EBV and consumption of Cantonese salted fish are closely associated with NPC. We investigated the prevalence of p53 mutations in 28 primary NPC specimens from white (including Hispanic) and African-American patients in Los Angeles, who are at low risk for NPC. Using PCR-based single-strand conformational polymorphism and direct sequencing, we found four mutations (14%) in exons 5-8 of the p53 gene in four patients. All were C-to-T transition mutations: two were present in exon 5-one at codon 142 [CCT (Pro)-->CTT (Leu)] and another at codon 144 [CAG (Gln)-->TAG (stop codon)]. The other two mutations were identified in exon 8: one at codon 273 [CGT (Arg)-->CAT (His)], a CpG site, and one at codon 271, a silent mutation [GAG (Glu)-->GAA (Glu)]. This is the first report investigating the presence of p53 missense mutations in NPC among a low-risk population. Our data indicate that p53 is also an infrequent event among NPC patients at low risk for the disease.