Dear Editor,
We read with great interest the recent publication by Ramis IB et al, who investigated Helicobacter pylori virulence factors in Brazilian dyspeptic patients11. Ramis IB, Vianna JS, Silva Junior LV, Groll AV, Silva PEA. cagE as a biomarker of the pathogenicity of Helicobacter pylori. Rev Soc Bras Med Trop 2013;46:185-189.. It has been firmly shown that no reliable diagnostic biomarkers exist to predict a specific disease outcome after primary colonization of H. pylori, although this has become an interesting area of research on this important microorganism worldwide. Many studies had been conducted to test/validate proper disease-related biomarkers of H. pylori. Recent findings based on sequencing and proteomic technologies have suggested new determinants as virulence factors that are disease-specific for H. pylori22. Abadi AT, Taghvaei T, Wolfram L, Kusters JG. Infection with Helicobacter pylori strains lacking dupA is associated with an increased risk of gastric ulcer and gastric cancer development. J Med Microbiol 2012;61:23-30.,33. Abadi ATB, Rafiei A, Ajami A, Hosseini V, Taghvaei T, Jones KR, et al. Helicobacter pylori homB, but Not cagA, Is Associated with Gastric Cancer in Iran. J Clin Microbiol 2011; 49:3191-3197.. Ramis IB et al found that cagA/cagE/babA2/vacAm1s1/iceA1 was a significant biomarker among only 15% (4/26) of their entire investigated population11. Ramis IB, Vianna JS, Silva Junior LV, Groll AV, Silva PEA. cagE as a biomarker of the pathogenicity of Helicobacter pylori. Rev Soc Bras Med Trop 2013;46:185-189.. Indeed, the conclusion in this study is based on a very small number of H. pylori strains (57 isolates), which cannot serve as a proper sample size from which to draw a comprehensive conclusion. Furthermore, the presence of a gene alone is not sufficient to suggest that it is a virulence factor. Gene expression analysis or proteomic tests are needed to identify true biomarkers of H. pylori that are associated with certain gastroduodenal diseases. Undeniably, additional in vitro and in vivo studies are necessary to elucidate the relationship between the H. pylori cagE gene and pathologic findings. It may be advisable to design a prospective study with different samples from other originating populations, and larger groups will be required to enhance the preliminary hypothesis stated in the current study. Moreover, it has been broadly recognized that gastroduodenal diseases are quite complicated outcomes of a variety of parameters, including environmental factors and host genetics. Additional in-depth studies are required to define a true biomarker for Helicobacter pylori-associated gastroduodenal disorders. Another controversial issue in the field of H. pylori biomarker and disease research is whether physicians can use this type of data in clinical trials. While characterizing accurate H. pylori biomarkers associated with certain diseases seems difficult, new, full-genome sequencing studies may answer unsolved related issues in the near future.
REFERENCES
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1Ramis IB, Vianna JS, Silva Junior LV, Groll AV, Silva PEA. cagE as a biomarker of the pathogenicity of Helicobacter pylori. Rev Soc Bras Med Trop 2013;46:185-189.
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2Abadi AT, Taghvaei T, Wolfram L, Kusters JG. Infection with Helicobacter pylori strains lacking dupA is associated with an increased risk of gastric ulcer and gastric cancer development. J Med Microbiol 2012;61:23-30.
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3Abadi ATB, Rafiei A, Ajami A, Hosseini V, Taghvaei T, Jones KR, et al. Helicobacter pylori homB, but Not cagA, Is Associated with Gastric Cancer in Iran. J Clin Microbiol 2011; 49:3191-3197.
Publication Dates
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Publication in this collection
Jul-Aug 2013
History
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Received
22 May 2013 -
Accepted
24 June 2013
