Cytokine gene polymorphisms and breast cancer susceptibility and prognosis

Single nucleotide polymorphisms (SNPs) in the promoter regions of cytokine genes are associated with differential levels of cytokine expression. We hypothesized that these SNPs might influence breast tumour development and progression by affecting the efficiency of the antitumour immune response and/or pathways of angiogenesis. A total of 144 female breast cancer patients and 263 cancer-free population controls were genotyped for the interleukin (IL)-1beta-511 (T/C), IL-6 -174 (G/C), tumour necrosis factor (TNF)-alpha-308 (A/G), IL-10 -1082 (A/G), IL-8 -251 (A/T) and vascular endothelial growth factor (VEGF) -1154 (A/G) SNPs, using amplification refractory mutation system polymerase chain reaction (ARMS-PCR) and TaqMan(R) (Applied Biosystems, Foster City, CA, USA) 5' nuclease assays for allelic discrimination. No significant associations were seen. Patient-control comparisons revealed a non-significant trend for association between the TNF-alpha-308 GG genotype and breast cancer compared to controls (79.7 vs. 68.2%, P = 0.03, P-c = 0.54). Stratification of the patient group according to the Nottingham Prognostic Index and individual prognostic factors revealed trends for association between IL-6 -174 GC and IL-8 -251 AA genotypes and markers of poor prognosis (P = 0.04, P-c = 0.72 and P = 0.02, P-c = 0.36, respectively). There were also trends for associations between VEGF -1154 AG and IL-1beta-511 TC genotypes and markers of good prognosis (P = 0.02, P-c = 0.36 and P = 0.05, P-c = 0.90, respectively). These results suggest that the role of cytokine promoter SNPs in both susceptibility to and prognosis in breast cancer requires further investigation in a larger study.