TAS2R38 polymorphisms, Helicobacter pylori infection and susceptibility to gastric cancer and premalignant gastric lesions

Background: Gastric cancer is worldwide the fourth more common cancer type by incidence, and the third by mortality. We analyzed three missense variants of TAS2R38 gene: rs713598 (A49P), rs1726866 (V262A), and rs10246939 (I296V). These variants and their combination in haplotypes (proline, alanine and valine/tasters or alanine, valine and isoleucine/nontasters) and diplotypes are responsible for individual differences in bitter perception. The single-nucleotide polymorphisms and the related phenotypes are known to be associated with susceptibility to Gram-negative bacterial infections, such as Helicobacter pylori, and with risk of various cancer types. An association between intermediate tasters (as defined by TAS2R38 diplotypes) and increased risk of gastric cancer was reported in a Korean population. Methods: We analyzed 2616 individuals of Latin American origin, representing the whole spectrum of lesions from gastritis to gastric cancer. Results: Comparing cancer cases vs. noncancers we observed a decrease in risk associated with heterozygous carriers of rs10246939 (P = 0.006) and rs1726866 (P = 0.003) when compared with homozygotes of the more common allele. Also, the analysis of diplotypes/phenotypes reflected the same association, with super-tasters showing a borderline increased risk of developing gastric cancer compared to medium-tasters [odds ratio (OR) = 1.63; 95% confidence interval (CI), 1.04-2.56; P = 0.033]. Also, nontasters showed an increased risk when compared to medium-tasters although not reaching statistical significance (OR = 1.58; 95% CI, 0.80-2.87; P = 0.203). We also tested the interactions between the TAS2R38 genotypes and H. pylori cagA status in a subset of samples and found no interaction. Conclusion: In conclusion, our results suggest only a modest contribution of TAS2R38 gene genetic variability in gastric cancer etiology.