The protective role of polymorphism MKK4-1304 T>G in nasopharyngeal carcinoma is modulated by Epstein-Barr virus' infection status.

MKK4 is a candidate tumor suppressor, which acts as a critical mediator of Epstein-Barr Virus (EBV)-induced c-Jun N-terminal kinase (JNK) activation. Functional polymorphism MKK4 -1304T>G has been showed to be protective in colorectal cancer or lung cancer. We hypothesized that genetic variants in the MKK4 promoter were associated with the risk of nasopharyngeal carcinoma (NPC). Two common polymorphisms in MKK4, -1304T>G and -1044A>T were genotyped in two independent case-control panels of Eastern and Southern Chinese populations, totally containing 1237 NPC and 1328 controls. We found that compared to the most common -1304TT genotype, carriers of variant genotypes (-1304TG+GG) were associated with a significantly reduced risk for NPC in total subjects (adjusted OR = 0.78; 95%CI = 0.67-0.94). Further stratification analysis showed that the protective effect was more pronounced in EBV negative status (adjusted OR = 0.51; 95%CI = 0.41-0.68) but restrained in those with EBV infection (adjusted OR = 1.05; 95%CI = 0.88-1.26), and that the -1304GG variant genotypes interacted with EBV negative status on reducing cancer risk (p = 0.011). However, no significant association was observed between the -1044A>T polymorphism and risk of NPC. Our data suggest that the protective role of genetic variant MKK4 -1304T>G is restrained in NPC with EBV infection. These findings implicate the role of EBV and MKK4 -1304 T>G interaction as a causative factor for the NPC.