Single nucleotide polymorphism of transforming growth factor-β1 and interleukin-6 as risk factors for ovarian cancer

Introduction
We investigated the association between common variants in TGF-1, IL-6 and the risk of ovarian cancer (OC) in Tunisian patients and control women.

Material, methods and results
Study subjects comprised 71 OC cases and 74 control women. Genotyping of TGF-1 and IL-6 SNPs was done by real-time PCR. No differences were noted in the minor allele frequencies of the three TGF-1 SNPs between OC patients and controls. However, marked differences in the distribution of TGF-1 rs1800469 genotypes were seen between OC cases and controls (p < 0.001), with TGF-1 rs1800469 heterozygous (C/T) genotype being negatively associated with OC (OR [95% CI] = 0.24 [0.15-0.58]). The allelic and genotypic distributions at IL-6 polymorphisms showed a positive association between minor allele (G) at IL-6 rs1880242 variant (p = 0.0275; R [95% CI] = 1.88 [1.03-3.46]) and the occurrence of OC. In fact, the presence of T allele [G/T + T/T] decrease the risk of OC (p = 0.021; OR [95% CI] = 0.38 [0.17-0.88]). In addition, the Haploview analysis demonstrated high linkage disequilibrium (LD) between IL-6 SNPs and eight-locus haplotype analysis identified that GGAGGGGA and GGAGGGTA haplotypes are positively associated with OC risk. A negative association was shown between IL-6 haplotype (TGGGCCTA) and OC occurrence.

Conclusions
Our results suggest that TGF-1 rs1800469, IL-6 rs1880242 variants and IL-6 haplotype (TGGGCCTA) have protective roles of OC risk. IL-6 haplotypes (GGAGGGGA and GGAGGGTA) increase OC susceptibility among Tunisian women.