The p53 gene is frequently mutated in various human tumors. Polymorphism is an additional genetic alteration observed in exons and introns of the p53 gene of normal tissues and tumors. Distributions of alleles of three common polymorphisms of the p53 gene; a 16 bp duplication in intron 3, codon 72 of exon 4 and a sequence in intron 6, were studied in peripheral white blood cells (WBC) of patients with ovarian or endometrial carcinomas. The analysis was performed by PCR and direct sequencing. The 100% linkage observed between the most common haplotypes of each polymorphism in healthy subjects was lower in the patients. A significant difference was observed between frequencies of genotype and haplotype combinations in patients with ovarian carcinoma and endometrial carcinoma. The incidence of heterozygosity was increased in ovarian carcinoma and decreased in endometrial carcinoma. Our results suggest that the p53 gene may be involved in susceptibility and predisposition to various cancers not only by mutations but also by preferential presentation of polymorphic alleles.

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