The effect of functional MAPKAPK2 copy number variation CNV-30450 on elevating nasopharyngeal carcinoma risk is modulated by EBV infection.

UNLABELLED Mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2) is recognized as oncogenic and simulative role on tumorigenesis by virtue of abnormal expression in cancer including nasopharyngeal carcinoma (NPC). We hypothesized that the copy number variation (CNV)-30450, which duplicates the MAPKAPK2 promoter, may affect MAPKAPK2 expression and be associated with NPC risk. In two independent case-control panels of southern and eastern Chinese with a total of 1590 NPC patients and 1979 cancer-free controls, we investigated the association between CNV-30450 and NPC risk by genotyping the CNV-30450 with the TaqMan assay, and tested its biological effect. Consistent findings were observed in the two populations, that the increased copy number of CNV-30450 was associated with increased risk of NPC (3/4-copy versus 2-copy: odds ratio = 1.28, 95% confidence interval = 1.10-1.49), in which lies a biological mechanism that the adverse genotypes enhanced the promoter activity of MAPKAPK2 and elevated MAPKAPK2 expression. Moreover, the CNV-30450 adverse genotypes significantly interacted with Epstein-Barr virus (EBV) infection on increasing NPC risk (P = 0.035), and the genotype-phenotype correlation was only significant in EBV-positive cases (P = 0.037) but not in EBV-negative ones (P = 0.366). These data suggest that the functional CNV-30450 in the MAPKAPK2 promoter elevates the NPC risk with a modulation by EBV infection, which may be an indicator of susceptibility to NPC. SUMMARY This case-control study suggests that the functional CNV-30450 in the MAPKAPK2 promoter elevates the NPC risk with a modulation by EBV infection, which may be an indicator of susceptibility to NPC.