Genotyping targets individuals at high risk for H. pylori-associated stomach cancer

A new study indicates that people carrying certain strains of the Helicobacter pylori bacterium who also have specific genetic polymorphisms are more likely to develop stomach cancer than others. The findings appear in the November 20 issue of the Journal of the National Cancer Institute.

People infected with H. pylori have an increased risk of stomach cancer, but many of these people will never develop the disease. Past studies have suggested that disease progression depends on a number of factors, including the bacterial strain and genetic variations in the host.

To determine whether certain combinations of bacterial and host genotypes increase the risk of stomach cancer, Céu Figueiredo, Ph.D., of the Institute of Molecular Pathology and Immunology at the University of Porto in Portugal, and colleagues examined 221 people with chronic gastritis and 222 people with stomach cancer.

The authors found that certain combinations of bacterial and host genotypes were strongly associated with the risk of stomach cancer. For example, people carrying a high-activity version of interleukin-1 beta gene who were infected by an H. pylori strain with a particular variant of the vacA vacuolating cytotoxin had a nearly 90-fold increase in the risk of stomach cancer.

"Our findings indicate that H. pylori and host genotyping can be important in better defining disease risk and preferentially targeting H. pylori eradication to high-risk individuals," the authors conclude.

In an accompanying editorial, Martin Blaser, M.D., of the New York University School of Medicine, says that these findings are promising, but he cautions that it still too early to generalize from this work.

"The study needs confirmation, different ethnic groups must be examined, the technique must be simplified for general use, and our understanding of the risks and benefits of H. pylori must grow," he writes. "Nevertheless, assessing risk for gastric diseases now is becoming a tractable problem and may ultimately prove to be a paradigm for other microbially induced diseases."

Contact: Céu Figueiredo or José Carlos Machado, Institute of Molecular Pathology and Immunology at the University of Porto,
35-122-557-0765;
fax: 35-122-557-0799,
ceu.figueiredo@ipatimup.pt or josem@ipatimup.pt

Editorial: Pamela McDonnell, NYU School of Medicine, 212-404-3555, Pam.McDonnell@med.nyu.edu.

Figueiredo C, Machado J, Pharoah P, Seruca R, Sousa S, Carvalho R, et al. Helicobacter pylori and interleukin 1 genotyping: An opportunity to identify high-risk individuals for gastric carcinoma. J Natl Cancer Inst 2002;94:1680–7.

Editorial: Blaser M. Polymorphic bacteria persisting in polymorphic hosts: Assessing helicobacter pylori-related risks for gastric cancer. J Natl Cancer Inst 2002;94:1662–3.

Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.

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