A genome-wide association study identifies ITGA9 conferring risk of nasopharyngeal carcinoma

To identify a gene(s) susceptible to nasopharyngeal carcinoma (NPC), we carried out a genome-wide association study (GWAS) through genotyping of more than 500 000 tag single-nucleotide polymorphisms (SNPs), using an initial sample set of 111 unrelated NPC patients and 260 controls of a Malaysian Chinese population. We further evaluated the top 200 SNPs showing the smallest P-values, using a replication sample set that consisted of 168 cases and 252 controls. The combined analysis of the two sets of samples found an SNP in intron 3 of the ITGA9 (integrin-alpha 9) gene, rs2212020, to be strongly associated with NPC (P = 8.27 x 10(-7), odds ratio (OR) = 2.24, 95% confidence intervals (CI) = 1.59-3.15). The gene is located at 3p21 which is commonly deleted in NPC cells. We subsequently genotyped additional 19 tag SNPs within a 40-kb linkage disequilibrium (LD) block surrounding this landmark SNP. Among them, SNP rs189897 showed the strongest association with a P-value of 6.85 x 10(-8) (OR = 3.18, 95% CI = 1.94-5.21), suggesting that a genetic variation(s) in ITGA9 may influence susceptibility to NPC in the Malaysian Chinese population. Journal of Human Genetics (2009) 54, 392-397; doi: 10.1038/jhg.2009.49; published online 29 May 2009