Monday, April 7, 2008

Today's pick: Toxigenic Helicobacter pylori Infection and Gastric Cancer risk to Relatives

I read this article (Argent et al., Clinical Cancer Research 2008 14:2227 -2235) today and quickly gauged that its going to be a citation classic. I submitted an evaluation to F1000Medicine where it was rated as an exceptional article that can change clinical practice ( Since F1000 Medicine is a paid service, not many can see the evaluation. I therefore, take liberty to provide here a simplified version of the evaluation:

This beautiful article provides yet another evidence linking virulent Helicobacter pylori infection to gastric cancer development. The paper describes a novel finding of early childhood transmission of H. pylori among the non-cohabiting relatives of gastric cancer patients. Such patients share with their non-cohabiting relatives the strains that have variable virulence potentials finetuned through microevolution. This work has important clinical implications for the families of gastric cancer patients. Author's investigation of gastric cancer families shows that strains are usually shared. However, this should not mean that different individuals have H. pylori with the same virulence potentials. Toxigenic (vacA type s1/m1) H. pylori was shown to be associated with precancerous gastric hypochlorhydria. Adult family members with this type of H. pylori harbored the same strain as those colonizing their currently noncohabiting adult family members in 68% cases; this simply means acquisition during childhood from each other or a source of infection common to the entire family. The authors believe that the clinical practice should change such that young relatives of cancer patients should be compulsarily screened for H. pylori, and the safest option they suggest to treat all who are positive. Beside this, the paper comprises an excellent approach to study microevolution in a persistent organism as an important measure of virulence gain or loss on a short time scale during colonization. The frequency with which microevolution of virulence factors occurs within families has important bearings for bacterial persistence and thereby the development of atrophic gastritis which preceded transformation to precancerous lesions.

Changes Clinical Practice: It should be compulsory for young relatives of gastric cancer patients to be screened for Helicobacter pylori and all who are positive should be treated.

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