Polymorphisms of tumour necrosis factors A and B in breast cancer

Abstract

We assayed for germline single nucleotide polymorphisms (SNPs) in the TNFB and TNFA genes in patients with breast cancer. SNPs were observed in the first intron of TNFB (G/A) and at -1031 (T/C), -863 (C/A), -857 (C/T) and -308 (G/A) in the promoter region of TNFA from peripheral leucocytes in 95 breast cancer patients and 190 healthy subjects as controls. The TNFB*G/TNFB*G homozygote (23.2% vs. 5.8%, P= 0.001) was predominant in patients, while the TNFB*A/TNFB*A homozygote was less frequent in patients (34.7% vs. 46.3%, P = 0.041) than in the control subjects. Breast cancer was not associated with SNPs in the TNFA promoters. Although the TNFB SNP failed to associate with any clinicopathological parameter of breast cancer, a substantial difference in pathology among tumour stages for the -857 SNP in TNFA was detected. These results indicate that TNFB has both tumorigenic and antitumorigenic capabilities depending on the genotype: the TNFB SNP TNFB*G/TNFB*G genotype gave an increased risk for breast cancer and that of TNFB*A/TNFB*A gave resistance to breast cancer (OR = 5.3395%; CI: 2.33-12.19). The results suggest that the TNFB*G allele plays some role in the tumorigenesis or activation of dormant tumour cells, but the TNFB*A allele induces some function(s) leading to the inhibition of tumorigenesis.