Functional IL-18 promoter gene polymorphisms in Tunisian nasopharyngeal carcinoma patients

Objectives: There is growing evidence suggesting that IL-18 levels may affect individual to virus-associated neoplasia and that single nucleotide polymorphisms (SNPs) within the gene may influence its production. In this study we wanted to know whether IL-18 polymorphisms at positions −607 C/A and −137 G/A are associated with susceptibility and/or are markers of nasopharyngeal carcinoma (NPC) prognosis. Methods: Using the restriction fragment length polymerase chain reaction (RFLP-PCR), 163 Tunisian patients and 164 healthy controls were genotyped. Results: No significant association was found between each studied polymorphism and NPC. However, we noted that the −607 A allele, which is associated with lower IL-18 production, increased the risk of advanced tumor stages (OR = 3.59; P = 0.017) and that this risk was more pronounced among the older patient's age at onset (OR = 3.85; P = 0.012). Moreover, the significant difference in CA/GG haplotype frequency distribution between young and older patients supported the idea that NPC disease has biologically different features between age sub-groups. Conclusion: Functional IL-18 gene polymorphisms do not influence the susceptibility to NPC in Tunisians but may contribute to disease onset and aggressiveness.