H. pylori, pepsinogen, and gastric adenocarcinoma

Dr. Kazumasa Miki, Japan
In this opening presentation, Dr. Miki described a case-control study of gastric cancer in Hawaii, that investigated the association of gastric adenocarcinoma with serum pepsinogens (PG) and antibodies to H. pylori and the CagA protein.
In total, 299 patients with gastric adenocarcinoma and 366 controls were included in the study. To evaluate the joint effect of H.pylori IgG or CagA positivity and low PG I on gastric cancer risk, subjects who were H.pylori and CagA negative and who had normal PG I levels as the referent group were identified.
Subjects seropositive for either H.pylori or CagA with low PG I levels had an elevated odds ratio of 9.21 (95% confidence interval (CI), 4.95–17.13) for non-cardia gastric cancer. When separated by histological classification, the odds ratio was 6.91 (95% CI, 3.53–13.53) for the intestinal type, and 40.74 (95% CI, 9.51–174.60) for the diffuse type of non-cardia gastric cancer. This pattern persisted when PG I/II ratio replaced PG I levels.
Dr. Miki stressed that these results emphasize the heightened risk for the diffuse histological type of gastric cancer associated with atrophy and CagA positive H.pylori strains. This strong association has not, however, been reported elsewhere and needs to be confirmed by others.
In conclusion, Dr. Miki emphasized that persons with both H.pylori or CagA seropositivity, and a low PG I level or a low PG I/II ratio, are at high risk for non-cardia gastric cancer. Furthermore, serum PG measurements and H.pylori/CagA assays may be benefical in serological screening strategies