Characterization of p53 gene mutations in a Brazilian population with oral squamous cell carcinomas.
Mutations in the p53 tumor suppressor gene are present in approximately 50% of all human cancers. We sought to determine the frequency and type of p53 mutations in squamous cell carcinomas (SCC) of the oral cavity in a Brazilian population. To identify p53 mutations we used PCR-SSCP in tumor tissue microdissected from paraffin- embedded and from fresh-frozen sections followed by direct sequencing of SSCP bands with altered electrophoretic mobility. We identified p53 mutations in 40% of the human SCC analyzed. The mutations were of a broad spectrum, with a preponderance of G --> A and A --> G transitions with an apparent hotspot at the CpG dinucleotide at codon 290. Patient samples were stratified according to tobacco and alcohol consumption as well as by anatomic location of the tumor, and although trends did emerge, no statistically significant associations were obtained between the occurance of TP53 mutations and these lifestyle habits. We conclude that p53 mutations are common among oral cavity cancers in this population, and stress the significance of this study since it is the first analysis of p53 mutation in oral cancer in a southern Brazilian population.
Chaves
Anna C M
AC
Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Cherubini
Karen
K
Herter
Nilton
N
Furian
Roque
R
Santos
Diogenes S
DS
Squier
Christopher
C
Domann
Frederick E
FE
D000328:Adult; D000368:Aged; D000428:Alcohol Drinking; D001483:Base Sequence; D001938:Brazil; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D003062:Codon; D018899:CpG Islands; D004247:DNA / Q000378:metabolism; D017931:DNA Primers / Q000494:pharmacology; D005091:Exons; D005260:Female; D016158:Genes, p53; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009062:Mouth Neoplasms / Q000235:genetics*; D009154:Mutation; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D012907:Smoking
D003062:Codon; D017931:DNA Primers; D004247:DNA