Helicobacter pylori CagA seropositivity and gastric carcinoma risk in a Japanese American populationNomura AM, Lee J, Stemmermann GN, Nomura RY, Perez-Perez GI, Blaser MJ
Helicobacter pylori colonization is associated with gastric cancer, but whether and to what extent the risk is greater for strains with the cagA gene than for those without needs to be determined. Between 1967 and 1977, 9963 Japanese American men were recruited and examined. By 1996, incident cases of gastric carcinoma of the distal stomach had been diagnosed in 261 men. Stored serum samples from these case patients and 261 age-matched control subjects were tested for immunoglobulin G antibodies to H. pylori and to the CagA product of H. pylori, using antibody-specific enzyme-linked immunosorbent assays. Compared with H. pylori-negative, CagA-negative men, H. pylori-positive, CagA-negative men had an odds ratio (OR) of 2.7 (95% confidence interval [CI], 1.3-5.6) for intestinal gastric carcinoma. Men seropositive for both H. pylori and CagA had an OR of 4.1 (95% CI, 2.2-7.7). This suggests that colonization by an H. pylori strain with the cagA gene is associated with a greater risk of intestinal gastric carcinoma.
J Infect Dis. 2002 Oct 15;186(8):1138-44. Epub 2002 Sep 25. PMID: 12355365
Relation between Helicobacter pylori CagA status and risk of peptic ulcer diseaseNomura AM, Pérez-Pérez GI, Lee J, Stemmermann GN, Blaser MJ
Although colonization with any Helicobacter pylori strain is associated with peptic ulcer, it is uncertain whether the risk is greater with cagA(+) or cagA(-) strains, which differ in their biology. A nested case-control study was done, based on a cohort of 5,443 Japanese-American men examined on the Hawaiian island of Oahu from 1967 to 1970. A total of 150 men with gastric ulcer, 65 with duodenal ulcer, and 14 with both diseases were identified. The authors matched the 229 cases with 229 population controls and tested their serum for immunoglobulin G antibodies to H. pylori and immunoglobulin G antibodies to the cagA product of H. pylori using enzyme-linked immunosorbent assays. Persons with H. pylori positivity had an odds ratio of 4.0 (95% confidence interval (CI): 1.9, 8.5) for gastric ulcer and 2.5 (95% CI: 0.8, 7.4) for duodenal ulcer. For CagA positivity, the odds ratios were 1.4 (95% CI: 0.9, 2.4) for gastric ulcer and 2.6 (95% CI: 1.1, 5.8) for duodenal ulcer. Subjects who were seropositive for both H. pylori and CagA had an odds ratio of 4.4 (95% CI: 1.8, 10.5) for gastric ulcer and 5.8 (95% CI: 1.1, 30.0) for duodenal ulcer. The results suggest that colonization with a cag(+) H. pylori strain elevates the risk beyond that of a cag(-) H. pylori strain for both gastric and duodenal ulcers.
Am J Epidemiol. 2002 Jun 1;155(11):1054-9. PMID: 12034584
Gastric cancer among the Japanese in HawaiiNomura AM, Stemmermann GN, Chyou PH
The incidence rate of gastric cancer among men of Japanese ancestry living in Hawaii is about one-third as high as that of their counterparts living in Japan. Because of this difference, a prospective study was conducted to identify factors related to the development of gastric cancer in Hawaii. Eight thousand and six (8,006) men born from 1900-1919 were examined from 1965 to 1968 and followed for over 25 years. During this time, 250 incident cases of gastric cancer were identified. The study has found the following: 1) prior infection with Helicobacter pylori bacteria increased the risk for stomach cancer; 2) cigarette smoking was positively associated with gastric cancer with age at which smoking started being an important risk factor; 3) after taking cigarette smoking into account, alcohol intake was not related to stomach cancer risk; 4) a low pepsinogen I level identified subjects at increased risk for the intestinal histologic type of gastric cancer; 5) a low serum ferritin level was a marker for increased risk of stomach cancer; 6) there was a weak indication that the intake of vegetables and fruits was inversely related to gastric cancer; 7) there was no association of stomach cancer with levels of serum cholesterol, serum uric acid, serum micronutrients (retinol, beta-carotene or alpha-tocopherol) or blood hematocrit; 8) there was also no association of gastric cancer with body mass index or physical activity.
Jpn J Cancer Res. 1995 Oct;86(10):916-23. PMID: 7493909
Infection with Helicobacter pylori strains possessing CagA is associated with an increased risk of developing adenocarcinoma of the stomachBlaser MJ, Perez-Perez GI, Kleanthous H, Cover TL, Peek RM, Chyou PH, Stemmermann GN, Nomura AM
To determine whether infection with a Helicobacter pylori strain possessing cagA is associated with an increased risk of development of adenocarcinoma of the stomach, we used a nested case-control study based on a cohort of 5443 Japanese-American men in Oahu, Hawaii, who had a physical examination and a phlebotomy during 1967 to 1970. We matched 103 H. pylori-infected men who developed gastric cancer during a 21-year surveillence period with 103 H. pylori-infected men who did not develop gastric cancer and tested stored serum specimens from patients and controls for the presence of serum IgG to the cagA product of H. pylori using an ELISA. The serum IgG assay using a recombinant CagA fragment had a sensitivity of 94.4% and a specificity of 92.5% when used in a clinically defined population; serological results were stable for more than 7 years. For men with antibodies to CagA, the odds ratio of developing gastric cancer was 1.9 (95% confidence interval, 0.9-4.0); for intestinal type cancer of the distal stomach, the odds ratio was 2.3 (95% confidence interval, 1.0-5.2). Age < 72 years and advanced tumor stage at diagnosis were significantly associated with CagA seropositivity. We conclude that infection with a cagA-positive H. pylori strain in comparison with a cagA-negative strain somewhat increases the risk for development of gastric cancer, especially intestinal type affecting the distal stomach.
Cancer Res. 1995 May 15;55(10):2111-5. PMID: 7743510
LETTER TO THE EDITOR - Helicobacter pylori and peptic ulcerNomura AM, Chyou PH, Blaser MJ
To the Editor: We commend Nomura and coworkers (1) for using an existing cohort to increase our understanding of the relation between Helicobacter Pylori and peptic ulcer disease. However, the nested case-control design that was used has a few methodological problems. First, the case-control design was used in the context of a cohort design, and principles that apply to the cohort design should be respected. Specifically, the disease status (duodenal or gastric ulcer) at study entry is unknown.
Ann Intern Med. 1995 Mar;122(5):394-95 PMID: None