伊朗胃癌高发区和低发区人群中幽门螺杆菌 vacA d1/-i1 基因型的地理差异。

Helicobacter pylori vacA d1/-i1 genotypes and geographic differentiation between high and low incidence areas of gastric cancer in Iran.

机构信息

Department of Biology, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.

出版信息

Arch Iran Med. 2013 Jun;16(6):330-7.

Abstract

BACKGROUND

Helicobacter pylori (H. pylori)-specific genotypes have been closely correlated with an increased risk of gastric cancer (GC). The present study aimed to determine the distribution of H. pylori pathogenic genotypes amongst Iranians infected with strains representing European ancestry in areas with different GC incidence.

METHODS

A total of 138 H. pylori isolates from ten districts in Iran were used for genotyping.

RESULTS

The following genotypic frequency was observed: vacA s1 (94.9%), s2 (5.1%), m1 (24.6%), m2 (75.4%), d1 (39.9%), d2 (60.1%), i1 (40.6%), i2 (59.4%), iceA1 (76.8%), iceA2 (52.9%), iceA1/2 (29.7%), babA2 (40.6%), and cagA (65.9%). Hierarchical analyses of molecular variance (AMOVA) for the vacA d1, d2, i1, and i2 alleles and iceA1 and iceA1/2 genes found significant levels of genetic differentiation among populations (P < 0.05). Prevalence of the vacA d1, i1, and iceA1/2 (but not iceA1) genes and vacA d1/i1, vacA d1/iceA1, vacA d1/iceA1/2, vacA d1/cagA+, vacA i1/iceA1, vacA i1/iceA1/2, and vacA i1/cagA+ genotypes were significantly higher (>2- or 3-fold) among H. pylori isolates from high incidence GC areas that had age-standardized rates (ASRs) of >20/105 (max. 51.8/105) when compared with those from low incidence (ASRs <10/105) GC areas (P < 0.005, for the latter, P = 0.016). In contrast, the vacA d2/i2, m2/d2, and m2/i2 genotypes were significantly more prevalent in low compared to high incidence GC areas (P < 0.005). The results of Mantel's test only showed a low correlation between genetic and geographic distances for the iceA1 and iceA1/2 (but not vacA alleles, iceA2, babA2, and cagA) genes among ten districts of Iran (r = 0.098 and 0.074, respectively, P < 0.05).

CONCLUSIONS

We propose that the H. pylori vacA d1/-i1 genotypes, which are new determinants of GC, have tremendous potential for differentiating H. pylori strains from high and low incidence GC areas in Iran.

摘要

背景

幽门螺杆菌（H. pylori）特异性基因型与胃癌（GC）风险增加密切相关。本研究旨在确定在不同 GC 发病率地区代表欧洲血统的伊朗感染者中 H. pylori 致病基因型的分布。

方法

对来自伊朗 10 个地区的 138 株 H. pylori 分离株进行基因分型。

结果

观察到以下基因型频率：vacA s1（94.9%）、s2（5.1%）、m1（24.6%）、m2（75.4%）、d1（39.9%）、d2（60.1%）、i1（40.6%）、i2（59.4%）、iceA1（76.8%）、iceA2（52.9%）、iceA1/2（29.7%）、babA2（40.6%）和 cagA（65.9%）。对 vacA d1、d2、i1 和 i2 等位基因以及 iceA1 和 iceA1/2 基因的分子方差分析（AMOVA）分层分析发现，各人群间存在显著的遗传分化水平（P<0.05）。vacA d1、i1 和 iceA1/2（但不是 iceA1）基因以及 vacA d1/i1、vacA d1/iceA1、vacA d1/iceA1/2、vacA d1/cagA+、vacA i1/iceA1、vacA i1/iceA1/2 和 vacA i1/cagA+基因型的流行率在高 GC 发病率地区（年龄标准化率（ASR）>20/105（最高 51.8/105））的 H. pylori 分离株中明显高于低 GC 发病率地区（ASR<10/105）（P<0.005，后者 P=0.016）。相比之下，vacA d2/i2、m2/d2 和 m2/i2 基因型在低 GC 发病率地区的流行率明显高于高 GC 发病率地区（P<0.005）。Mantel 检验的结果仅表明，在伊朗的 10 个地区，iceA1 和 iceA1/2（但不是 vacA 等位基因、iceA2、babA2 和 cagA）基因的遗传和地理距离之间存在低度相关性（r=0.098 和 0.074，分别，P<0.05）。