Premium
Is the Association Between Helicobacter pylori and Gastric Cancer Confined to CagA‐Positive Strains?
Author(s) -
Held Maria,
Engstrand Lars,
Hansson LarsErik,
Bergström Reinhold,
Wadström Torkel,
Nyrén Olof
Publication year - 2004
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/j.1083-4389.2004.00222.x
Subject(s) - caga , helicobacter pylori , odds ratio , antibody , cancer , medicine , confounding , gastroenterology , risk factor , case control study , relative risk , antigen , immunology , confidence interval , virulence , biology , gene , genetics
Background. Infection with Helicobacter pylori is associated with an increased risk of gastric cancer. Several studies have indicated that the association differs with strain type. We aimed to find out if infection with strains lacking the virulence factor CagA is linked to gastric cancer risk. Materials and methods. In a hospital‐based case–control study, we collected sera from 100 case patients with a newly diagnosed gastric adenocarcinoma and 96 control patients with diseases unrelated to H. pylori status. Antibodies to H. pylori were analyzed by enzyme‐linked immunosorbent assay (ELISA), and antibodies to CagA were detected by immunoblot. Logistic regression was used to obtain odds ratios (ORs) as estimates of relative risk, adjusted for potential confounding. Results. Among the case patients, 81% were ELISA positive and 86% had antibodies to CagA. The corresponding numbers among the controls were 58% and 55%, respectively. ELISA positivity was associated with an increased risk of gastric adenocarcinoma compared to ELISA negativity (OR for gastric cancer regardless of site 3.9, 95% CI 1.9–8.2). The OR was 7.4 (95% CI 3.3–16.6) for CagA‐positive relative to CagA‐negative subjects. Among ELISA‐positive subjects the presence of CagA antibodies increased the risk 3.6 times (95% CI 1.2–11.1). ELISA‐positive CagA‐negative infections were associated with a fourfold increased risk (OR = 4.2, 95% CI 1.0–17.0) compared to no infection (ELISA‐negative and CagA‐negative). Conclusions. Although patients with antibodies to CagA have the greatest risk of developing gastric cancer, those with CagA‐negative infections run a significantly greater risk than uninfected persons.