Expression Analysis of miR-200a-3p, miR-223-5p and miR-29a-3p in Polymorphic Helicobacter Pylori CagA Genotypes in Gastric Cancer

Gastric cancer is the fifth most common malignancy in the world and is the leading third cause of cancer-related deaths. Helicobacter pylori contains cagA virulence factor, which is associated with gastric cancer development. It has been determined that sequence variations in the 3' variable region of the cagA gene (number of A, B, C EPIYA motifs and A,B,C and D cagA structure formed by the organization of R1, R2, R3 regions) affects gastric cancer risk. In particular, it has been shown that strains with C-type cagA containing more than one EPIYA-C motif increases gastric cancer risk. It has been detected that Helicobacter pylori virulence factor cagA, alters many miRNA expressions, including let-7. In this study, PCR analysis was performed to detect sequence variations in the 3 'variable region of the cagA gene of Helicobacter pylori strains isolated from cancerous stomach tissues. Expression changes of miR-200a-3p, miR-223-5p and miR-29a-3p miRNAs in cancerous stomach tissues infected with Helicobacter pylori were analyzed by quantitative real-time PCR. There was observed that a decrease in miR-200a-3p, miR-29a-3p expressions and a increase in miR-223-5p expression in infected tissues with strains with sequence variations in the 3 'variable region (ABC EPIYA motif A type cagA and AB-ABC EPIYA motifs A anD C type cagA).