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Amino acid polymorphisms flanking the EPIYA ‐A motif of H elicobacter pylori CagA C ‐terminal region is associated with gastric cancer in E ast C hina: Experience from a single center
Author(s) -
Chen Chun Yan,
Wang Fang Yu,
Wan Hai Jun,
Jin Xin Xin,
Wei Juan,
Wang Zhen Kai,
Liu Chang,
Lu Heng,
Shi Hui,
Li Dong Hai,
Liu Jiong
Publication year - 2013
Publication title -
journal of digestive diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 51
eISSN - 1751-2980
pISSN - 1751-2972
DOI - 10.1111/1751-2980.12056
Subject(s) - caga , helicobacter pylori , amino acid , gene , gastritis , microbiology and biotechnology , biology , chemistry , genetics , virulence
Objective The study aimed to investigate the relationship between gastroduodenal disease and the diversity of the cagA 3′ variable region and the amino acid polymorphisms in the Glu‐Pro‐Ile‐Tyr‐Ala (EPIYA) segments of the CagA C‐terminal region of H elicobacter pylori ( H. pylori ). Methods Gastric mucosal specimens from 170 patients in our center (Nanjing, Jiangsu Province, China) were collected and the genomic DNA of the H . pylori strains was extracted directly from biopsied specimens. Polymerase chain reaction (PCR) was used to amplify the cag A gene, and diversity in its 3′ variable region was assessed by direct sequencing. Results A total of 154 (90.6%) H . pylori isolates were cag A ‐positive, but the presence of this gene alone was not associated with the type of gastroduodenal disease. A total of 151 (88.8%) strains had the E ast A sian type EPIYA‐D sequence, most of which were of ABD subtype. Three isolates from patients with chronic gastritis possessed the EPIYA ‐ C segment. The sequences flanking the EPIYA motifs contained polymorphisms at seven residues, among which amino acid positions 878 and 879 had a statistically significant association with gastric cancer ( P = 0.021). Amino acid change from glycine to aspartic acid at residue 968 was present only in patients with gastric cancer (4/20) ( P < 0.001). Conclusions Most H . pylori strains present in our study are of the CagA ‐ ABD subtype. Polymorphisms at amino acids 878 and 879 flanking the EPIYA ‐A motif are statistically associated with gastric cancer.