Gastric cancer susceptibility in gastric cancer relatives: attributable risks of Macrophage migration inhibitory factor promoter polymorphism and Helicobacter pylori.

The purpose of this study is to assess attributable effects of Macrophage migration inhibitory factor (MIF) promoter region polymorphisms and Helicobacter pylori infection to the susceptibility to gastric cancer. 296 individuals from non-cardia gastric cancer case families and 319 individuals from control families were obtained from Henan Province, China. The results showed the frequencies of MIF (-173 C/C and -794 non-CATT(5)carrier) genotypes were significantly higher in the family members of gastric cancer cases than that in the controls family (-173: OR=2.59; -794: OR=2.65), and the ORs reduced with decreasing relative degrees. Multivariate analysis showed that MIF-173 C and -794 non-CATT(5) alleles synergized with H. pylori for the risk of gastric cancer (OR=14.64). The attributable risk percent (ARP) and the population attributable risk percent (PARP) attributed to interaction of MIF-173 C/C and MIF-794 non-CATT(5)carrier were 72.3% and 4.7%, respectively. The MIF risk genotypes and H. pylori conferred a joint ARP of 93.2% to gastric cancer. In summary, Possession of -173 G→C substitution and -794 non-CATT(5)carrier in the MIF promoter region are associated with increased susceptibility to non-cardia gastric cancer. H. pylori infection increases the risks of MIF polymorphisms for susceptibility with gastric cancer.