MTHFR, XRCC1 and OGG1 genetic polymorphisms in breast cancer: a case-control study in a population from North Sardinia

Background: Despite conflicting results, considerable evidence suggests the association between single nucleotide
polymorphisms in MTHFR, XRCC1 and OGG1 genes and, risk of developing breast cancer. Here a case-control study
is reported, including 135 breat cancer patients and 112 healthy women, all representative of Northern Sardinian
population.
Methods: Polymerase chain reaction/restriction fragment length polymorphism method was used to determine the
genotypes of five polymorphisms: MTHFR C677T (rs1801133) and A1298C (rs1801131), XRCC1 Arg194Trp (rs1799782)
and Arg399Gln (rs25487) and OGG1 Ser326Cys (rs1052133). Allelic, genotypic and haplotype association analyses
with disease risk and clinicopathological parameters were performed.
Results: A nominally significant association with breast cancer risk was observed for MTHFR C677T polymorphism
heterozygous genotype in the codominant model (OR: 0.57, 95% CI: 0.32–1.00, p = 0.049) and for Cys/Cys genotype
of the OGG1 Ser326Cys polymorphism in the recessive model (OR: 0.23, 95% CI: 0.05–1.11, p = 0.0465). No significant
differences were found at genotype-level for A1298C polymorphism of the MTHFR gene and Arg194Trp and
Arg399Gln of the XRCC1 gene. Furthermore, the OGG1 and XRCC1 rs25487 polymorphisms were nominally
associated with PgR, Her2 status and with sporadic breast cancer, respectively.
Conclusions: Based on genetic characteristics of individuals included in this study, results suggest that MTHFR CT
and OGG1 Cys/Cys genotypes have a protective effect that may have an influence on breast cancer risk in a
representative Northern Sardinian population.