Helicobacter pylori Seropositivities and Risk of Pancreatic Carcinoma
Menée en population chinoise auprès de 761 cas et de 794 témoins, cette étude évalue l'association entre une séropositivité pour Hélicobacter pylori et le risque de carcinome pancréatique
Background: Pathophysiologic actions of Helicobacter pylori colonization on gastric acidity have been hypothesized to modulate the effect of pancreatic carcinogens, through CagA-negative organism strain type, hyperchlorhydria and increased risk of pancreatic cancer, or CagA-positive strain, hypochlorhydria and decreased risk of pancreatic cancer. We aimed to determine H. pylori strain-specific associations with pancreatic cancer in a population where colonization by CagA-positive strains is common. Methods: We carried out a large population-based case-control study of pancreatic carcinoma in Shanghai, China. Venipuncture specimens were obtained from a representative sample of 761 case patients and 794 randomly selected control subjects matched by category of age and gender. Antibody seropositivity for H. pylori and its virulence protein CagA were determined by commercial enzyme-linked immunosorbent IgG assays. Results: Compared to individuals seronegative for both H. pylori and CagA, decreased pancreas-cancer risk was seen for CagA seropositivity (adjusted odds ratio [OR], 0.68; 95% confidence interval (CI), 0.54−0.84), while some increased risk was suggested for CagA-negative H. pylori seropositivity (OR, 1.28; 95% CI, 0.76−2.13). No risk interactions were observed between CagA seropositivity and gender, cigarette smoking, or age-21 body mass index. Conclusions: Similar to what has been seen in animal models, our results provide suggestive evidence in humans for the involvement of gastric acidity, through its bidirectional modification according to colonization by Helicobacter pylori CagA strain type, in the risk of pancreatic carcinoma. Impact: Helicobacter pylori colonization may have diverse effects on cancer risk, depending on the organism strain type as well as on the particular cancer site.