Associations between a PTPN11 polymorphism and gastric atrophy--opposite in Uzbekistan to that in Japan.

Src homology 2 domain-containing protein tyrosine phosphatase-2 (SHP-2) of gastric epithelial cells interacts with cagA from Helicobacter pylori (H. pylori). Our previous studies found the AA genotype of a G/A single nucleotide polymorphism at intron 3 (rs2301756) of PTPN11 gene, which encodes SHP-2, to be associated with a lower risk of gastric atrophy. The present study aimed to examine the association with gastric atrophy among the subjects of a case-control study of peptic ulcer disease (PUD) conducted in the Uzbek Republic. Cases were 95 patients (61 males and 34 females) with PUD aged 16 to 85 years. Controls were 102 hospital volunteers (42 males and 60 females) including 42 patients with miscellaneous diseases, aged 15 to 75 years. Gastric atrophy was evaluated with serum pepsinogens (PG1<70 ng/ml and PG1/PG2<3). Polymorphisms of PTPN11 at intron 3 (rs2301756) and intron10 (rs12229892) were genotyped with PCR with confronting two-pair primers (PCR-CTPP). Anti-cagA IgG antibody was detected in 93.7% of cases and 77.5% in controls. Gastric atrophy was observed in 24.2% of the PUD patients and 33.3% in the controls. The A allele at intron 3 was completely linked to the G allele at intron 10. The age, sex, and group (cases and controls) adjusted odds ratio of gastric atrophy was 0.18 (95% confidence interval, 0.04-0.86) for intron 3 GG genotype relative to AA genotype. Since the finding was opposite to that among Japanese, the H. pylori strains and/or lifestyle in Uzbekistan might modify the association.