The Prevalence of Helicobacter pylori Virulence Factors in Bhutan, Vietnam, and Myanmar Is Related to Gastric Cancer Incidence.

Tran Thi Huyen Trang,Miyuki Matsuda,Vu Van Khien,Varocha Mahachai,Thein Myint,Tran Thanh Binh,Yoshio Yamaoka,Ho D Q Dung,Seiji Shiota,Rumiko Suzuki,Lotay Tshering,Osamu Matsunari,Tomohisa Uchida,Ratha-Korn Vilaichone

doi:10.1155/2015/830813

Abstract

Gastric cancer is a significant health problem in Asia. Although the prevalence of Helicobacter pylori infection is similar in Bhutan, Vietnam, and Myanmar, the incidence of gastric cancer is highest in Bhutan, followed by Vietnam and Myanmar. We hypothesized that H. pylori virulence factors contribute to the differences. The status of cagA, vacA, jhp0562, and β-(1,3)galT(jhp0563) was examined in 371 H. pylori-infected patients from Bhutan, Vietnam, and Myanmar. Each virulence factor could not explain the difference of the incidence of gastric cancer. However, the prevalence of quadruple-positive for cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative was significantly higher in Bhutan than in Vietnam and Myanmar and correlated with gastric cancer incidence. Moreover, gastritis-staging scores measured by histology of gastric mucosa were significantly higher in quadruple-positive strains. We suggest that the cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative genotype may play a role in the development of gastric cancer.

Highlights

Many studies indicate that the highest incidence rate of gastric cancer (GC) is found in East Asia [1]
Because the differences in GC incidence can be explained in part by differences between H. pylori strains [9], we aimed to examine the prevalence of H. pylori virulence factors (cagA, vacA, jhp0562, and β-(1,3)galT) in three South Asian countries with different incidences of GC: Bhutan, Vietnam, and Myanmar
The prevalence of strains quadruple-positive for cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galTnegative was the highest in Bhutan, followed by Vietnam and Myanmar, which correlated with the incidence of GC reported in GLOBOCAN 2012

Summary

Introduction

Many studies indicate that the highest incidence rate of gastric cancer (GC) is found in East Asia (highest in Korea, followed by Mongolia, Japan, and China) [1]. The age standardized incidence rate (ASR) of GC is reported to be high in some countries such as Kazakhstan or Bhutan and to a lesser extent Vietnam, whilst it is lower in Myanmar and India (accessible at BioMed Research International http://globocan.iarc.fr/). Four years later, data from GLOBOCAN 2012 reported that the ASR of GC in Bhutan had fallen to 17.2 cases/100,000 per year. This was still higher than the ASR of GC in Vietnam and Myanmar, but lower than that of Kazakhstan (21.6/100,000 per year). We believe that the actual number of GC patients in Bhutan is higher than previously estimated

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