Abstract

PINTO, Yadira et al. Polymorphism of the P53 gen in familial breast cancer in a colombian population study group. rev. colomb. cir. [online]. 2007, vol.22, n.1, pp.17-26. ISSN 2011-7582.

Introduction: Gen p53 codifies a 53 KD protein, an important regulator of cell processes such as proliferation, cellular death (apoptosis), and the preservation of the genetic material. It is known as the "guardian of the genoma" and is frequently encountered in a mutated stated in as much as 50% of the human carcinomas. Variants in its sequence, or genetic polymorphism (in various regions of the gen), have been identified, and diverse studies have shown an association of the risk of developing breast cancer with the presence of such variants. The purpose of this cases-controls study was to analyze the association of the genotypes and the allelic frequencies of three of the polymorphisms of gen p53 with the risk of developing familial mammary cancer in a population group in Colombia. Polymorphisms studied were: in the gen´s exon 4, corresponding to codon 72 of the protein, where there may be an aginine or a proline (Arg72Pro); in the intron 3 (duplication of 16pb); and in the intron 6, where there could be found a guanine or an adenine (G/A). Materials and methods: 186 patients with familial breast cancer were studied, with 186 subjects as controls, determining the allelic and genotype frequencies by RFLPS analyses and measurement the force of association by the Odds Ratio (OR), with a significance of the association utilizing a Confidence Interval (CI) of 95% and the statistical program SPSS 11.5. Results. The genotype frequencies of codon 72 in the study population were: 61.3% for Arg/Arg, 32.3% for Pro/Arg, and 6.5% for Pro/Pro in the cases studied, and 44.1%, 45.7% and 10.2%, respectively, for the control subjects. The allelic frequency obtained for arginine in the cases studied were 77.4%, and 67.0% in the control subjects (P=0.004). An OR=2.19 with a 95% CI (1.33-3.63) was observed. The frequency of the genotypes of intron 6 were between the cases and the W/W controls (75.3% versus 82.3%), W/M (24.2% versus 15.6%), and M/M (0.5% versus 2.2%), while the values of the genotype intron 3 frequencies in the cases were: 90.3% for W/W, 8.6% for W/M, and 1.1% for M/M, and in the controls: 98.9% for W/W and 0.5% for W/M and M/M. The allelic frequencies for the silvester allelo (W) were 94.6% in the cases and 99.2% in the controls. An OR=17.86 with a 95% CI (2.25-141.84) was achieved. Conclusions: Our results in the Colombian population group studied show an important association of the Arg/Arg genotype of codon 72 (2 x) and the W/M intron 3 genotype (18 x) of gen p53 with the risk of developing familial mammary cancer.

Keywords : breast neoplasms; genetic polymorphism; gene p53; hereditary neoplastic syndromes.

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