Cytokine gene polymorphisms and breast cancer susceptibility.

Human breast cancer (BC) is characterized by a considerable clinical heterogeneity. Steroid hormone receptor expression and growth factor receptor expression have been considered suitable diagnostic and prognostic markers, whereas mutations of oncosuppressor and gatekeeper genes have been found associated with an increased risk for this malignancy. To evaluate the role that polymorphisms of genes involved in the regulation of inflammatory response might play in BC susceptibility, we investigated associations between cytokine functionally relevant polymorphisms in 84 BC patients compared to 110 age- and sex-matched controls. TNF-alpha (-308G/A), TGF-beta1 (+869C/T), IL-10 (-1117G/A; -854C/T; -627C/A), and IFN-gamma (874T/A) single nucleotide polymorphisms (SNPs) were identified by sequence-specific primers (SSP)-PCR or restriction fragment length polymorphism (RFLP)-PCR. Genotype or haplotype distributions for each polymorphisms were consistent with the HWE in these populations. We were unable to demonstrate differences in genotype or allele frequencies between patient and control groups. Data obtained in this study indicate that none of the cytokine SNPs studied is likely to have predisposing or protective effects on BC susceptibility. On the other hand, both positive and negative association with BC have been reported for some of the studied genotypes by different research groups. In conclusion, further studies involving larger numbers of subjects are required.