Genetic Factors Increase Cancer Risk from H pylori

A recent study based on the fact that both Helicobacter pylori genotype and host genetic polymorphisms play a role in determining the consequences of H pylori infection has shown that certain combinations of bacterial and host genotypes are particularly associated with the occurrence of gastric carcinoma. The study appeared in the November 20, 2002, issue of the Journal of the National Cancer Institute.

Investigators from the Institute of Molecular Pathology and Immunology at the University of Porto (Portugal) employed a polymerase chain reaction (PCR) line probe assay to determine genotypic variations in virulence-associated genes of H pylori vacA (s and m regions) and cagA in 221 subjects with chronic gastritis and 222 patients with gastric carcinoma.

Certain combinations of bacterial and host genotypes were found to be 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.

The authors concluded, "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.”




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