Abstract: Objective　To investigate the relationship of the single nucleotide polymorphisms and haplotypes of interleukin-18（IL-18）gene promoter with genetic susceptibility of nasopharyngeal carcinoma（NPC）. Methods　The single nucleotide polymorphisms of IL-18 gene promoter -137G/C（rs 187238 G/C）and -607C/A（rs 1946518 C/A）in 190 patients with NPC and 200 healthy controls were determined by polymerase chain reaction-restriction fragment length polymorphism（PCR-RFLP）. The frequency of haplotypes and linkage disequilibrium of IL-18 gene in different groups were analyzed. Results　The distributions of IL-18 gene -607C/A polymorphism had no statistical significance between NPC and control groups（P＞0.05），but the distributions of IL-18 gene -137G/C polymorphism were significantly different between them（P＜0.05）. The relative risk suffered from NPC group found that of C allele was 1.730 times of the G allele [odds ratio（OR）＝1.730，95%confidence interval（CI）: 1.227-2.439）]. Being consistent with the results of the genotyping analysis，IL-18 gene -137G/C and -607C/A single nucleotide polymorphisms showed strong linkage disequilibrium，and the frequency of the -137C/-607A haplotype in NPC group was significantly higher than that in control group（P＜0.05）. The -137C/-607A haplotype was associated with a significantly increased risk of NPC（OR＝1.699，95%CI：1.174-2.457）. Conclusions　IL-18 gene -137G/C polymorphism and its -137C/-607A haplotype are associated with NPC，and -137C allele is an important genetic susceptibility gene for NPC.

Key words: Interleukin-18, Nasopharyngeal carcinoma, Gene, Polymorphism