Functional polymorphisms of interleukin-18 gene and risk of breast cancer in a Brazilian population

Authors

  • L. K. d. C. Back,

    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
    2. Molecular Diagnostic, Biogenetika, Florianópolis, Brazil
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  • T. D. J. Farias,

    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
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  • P. A. da Cunha,

    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
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  • Y. C. N. Muniz,

    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
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  • M. C. M. Ribeiro,

    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
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  • B. L. Fernandes,

    1. Hospital Universitário (HU-UFSC), Universidade Federal de Santa Catarina, Florianópolis, Brazil
    2. Mastologia, Hospital e Maternidade Carmela Dutra, Florianópolis, Brazil
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  • C. K. Fernandes,

    1. Molecular Diagnostic, Biogenetika, Florianópolis, Brazil
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  • I. R. de Souza

    Corresponding author
    1. Departamento de Biologia, Embriologia e Genética (UFSC - BEG), Universidade Federal de Santa Catarina, Florianópolis, Brazil
    • Correspondence

      Ilíada Rainha de Souza

      Laboratório de Polimorfismos Genéticos

      Depto. BEG

      Centro de Ciências Biológicas

      Universidade Federal de Santa Catarina

      Campus Universitário

      setor F, ed. Fritz Müller

      sala 311. Trindade, Mailbox: 476

      Florianopolis

      SC 88040-900

      Brazil

      Tel: +55 (48) 37219804

      Fax: +55 (48) 37215148

      e-mail: rainha@ccb.ufsc.br

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Abstract

Interleukin-18 (IL-18) is a key cytokine responsible for immune response and involved in the process of cancer development. In this case–control study, we tested whether IL-18 promoter polymorphism contributes to breast cancer susceptibility in Brazilian patients. The two groups studied were 154 patients with breast cancer and 118 healthy individuals. The frequency of IL-18 promoter single nucleotide polymorphisms (SNPs) at positions −607 (C/A) (rs1946518) and −137 (G/C) (rs187238) was determined by polymerase chain reaction analyses. The polymorphisms genotyped in this study showed a significant association with breast cancer under different genetic models. Both SNPs showed a positive association. For the IL18-607 polymorphism the best model was the codominant genetic model [CC vs AA, P = 0.004, odds ratio (OR) = 2.782, 95% confidence interval (CI) 1.385–5.589]. For IL18-137 statistical significance was found using the recessive genetic model (P = 0.008, OR = 3.896, 95% CI 1.427–10.639). The association between the haplotypes of the IL18 gene and breast cancer was further confirmed. Our results suggest that IL18-607 and IL18-137 polymorphism contributes to increase the breast cancer risk. To our knowledge, this is the first report regarding Brazilian breast cancer patients and IL18 promoter polymorphisms.

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