Diversity of 3? variable region of cagA gene in Helicobacter pylori strains isolated from Chinese population

Abstract Background The cytotoxin-associated gene A ( cagA ) is one of the most important virulence factors Helicobacter pylori H. ). There a highly polymorphic Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region in C-terminal CagA protein. This thought to play an role pathogenesis gastrointestinal diseases. aim this study was investigate diversity 3? variable and amino acid polymorphisms EPIYA segments , their association with gastroduodenal Methods total 515 strains from patients 14 different geographical regions China were collected. genomic DNA each strain extracted amplified by polymerase chain reaction (PCR). PCR products sequenced analyzed using MEGA 7.0 software. Results 503 (97.7%) -positive 1,587 motifs identified, including 12 types or EPIYA-like sequences. In addition four reported major segments, several rare (e.g., B?, B? D?) defined 20 sequence ABD, ABC) found our study. 481 (95.6%) carried East Asian type CagA, ABD subtypes prevalent (82.1%). Only 22 Western which included AC, ABC, ABCC ABCCCC subtypes. CagA-ABD subtype had statistical difference (P = 0.006). seven sequences surrounding motifs, among acids 893 894 gastric cancer 0.004). Conclusions study, studied depth. Chinese population, its presence associated Amino at residues flanking statistically significant cancer.