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DNA repair gene polymorphisms and susceptibility to familial breast cancer in a group of patients from Campinas, Brazil
Rozany Mucha Dufloth1,3, Sandra Costa5, Fernando Schmitt3,4 and Luiz Carlos Zeferino1,2
1Centro de Atenção Integral à Saúde da Mulher (CAISM), Universidade Estadual de Campinas, Campinas, SP, Brasil
2Departamento de Ginecologia e Obstetrícia, Faculdade de Ciências Médicas,
Universidade Estadual de Campinas, Campinas, SP, Brasil
3Instituto de Patologia e Imunologia Molecular, Universidade do Porto, Porto, Portugal
4Faculdade de Medicina, Universidade do Porto, Porto, Portugal
5Instituto de Ciências da Vida e da Saúde, Universidade do Minho, Braga, Portugal
Corresponding author: L.C. Zeferino
E-mail: zeferino@caism.unicamp.br
Genet. Mol. Res. 4 (4): 771-782 (2005)
Received January 26, 2005
Accepted October 24, 2005
Published December 21, 2005

ABSTRACT. Several studies have reported that the genes involved in DNA repair and in the maintenance of genome integrity play a crucial role in protecting against mutations that lead to cancer. Epidemiologic evidence has shown that the inheritance of genetic variants at one or more loci results in a reduced DNA repair capacity and in an increased risk of cancer. Polymorphisms have been identified in several DNA repair genes, such as XRCC1, XPD, XRCC3, and RAD51, but the influence of specific genetic variants on repair phenotype and cancer risk has not yet been clarified. This was a case-control study design with three case groups: 53 women with breast cancer and family history; 33 women with sporadic breast cancer; 175 women with no breast cancer but with family history. The control group included 120 women with no breast cancer and no family history. The PCR-RFLP method was used to analyze the XRCC1-Arg399Gln, XPD-Lys751Gln, XRCC3-Thr241Met, and RAD51-G135C polymorphisms. No statistically significant differences were found between the case groups and the control group for any of the polymorphisms analyzed, and also between the breast cancer and family history group and the sporadic breast cancer group. Sample sizes of women with breast cancer, whether familial or sporadic, were insufficient to show any small true differences between the groups, but we have to consider that currently there is no clear consensus with respect to the association of these polymorphisms with breast cancer risk. Considering the data available, it can be conjectured that if there is any risk association between these single-nucleotide polymorphisms and breast cancer, this risk will probably be minimal. The greater the risk associated with cancer, the smaller the sample size required to demonstrate this association, and the data of different studies are usually, therefore, more concordant.

Key words: Breast cancer, XRCC1-Arg399Gln, XPD-Lys751Gln, XRCC3-Thr241Met,
RAD51-G135C, Polymorphisms

 

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