Evaluation of the associations between the single nucleotide polymorphisms of the promoter region of the tumor necrosis factor-α gene and nasopharyngeal carcinoma

Background: Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine and may act as an endogenous tumor promoter. Single nucleotide polymorphisms (SNPs) of the TNF-α gene promoter region have been found to be associated with certain cancers. We conducted a case-control study to evaluate the association between these SNPs and nasopharyngeal carcinoma (NPC). Methods: We used polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine the -308 TNF-α promoter genotypes of 89 NPC patients and 360 healthy controls. In 23 NPC patients and 50 controls, we determined the sequence from -1065 to -101 nucleotides of the TNF-α gene promoter region to detect SNPs. Results: In comparison with the controls, the NPC patients had higher proportions of men and carriage of IgA antibodies against the capsid antigen of Epstein-Barr virus, but had a similar carrier rate of the -308A allele (odds ratio [OR], 1.2; 95% confidence interval [CI], 0.7-2.0). The carriage of the -308A allele was not associated with the occurrence of NPC in comparison with -308G homozygosity. We also found no significant differences in the distributions of allelic variants of the -1031, -863, -857, and -806 loci of the TNF-α promoter region, but observed a lower carrier rate of the novel -806T allele in the NPC patients (OR, 0.3; 95% CI, 0.0-2.9). Conclusion: Allelic variants of the TNF-α promoter gene may not be used as biomarkers of susceptibility to NPC. The role of the -806T allele needs to be studied further.