Evaluation of Gene Expression Alterations of ATM, TP53, and POLM in Gastric Biopsy Specimens of Patients with Gastritis and its Association with Helicobacter Pylori Infection

Gastritis is one of the most common diseases affecting the stomach. Helicobacter pylori infection could lead to DNA damage in gastric epithelial cells, followed by error-prone DNA repair pathways that increase the accumulation of damage at the site of DNA double-stranded breaks, exacerbate genome instability, and facilitate the emergence of gastric cancer. This study aimed to examine the expression level of ATM, POLM, and TP53 genes involving in the DNA Damage Response and the cell cycle arrest in the gastric precancerous stage.

Among 180 gastric biopsy specimens, 30 samples taken from patients with moderate chronic gastritis infected by H. Pylori were regarded as the case group, and 30 other samples taken from non-infected patients with mild chronic gastritis were regarded as control. Following that, RNA extraction and cDNA synthesis was performed. Afterward, the expression levels of ATM, POLM, and TP53 genes were evaluated by the Real-Time PCR method. Ethics code: 98-02-27-43392

The ATM, POLM, and TP53 genes in the cases showed a 4.07, 3.35, and 5.13 increase in the gene expression at the transcriptional level, compared to the controls.

In general, ATM, POLM, and TP53 genes showed a higher increased expression level in the case group, compared to the controls, which might indicate the activation of noted genes after H. pylori infection. This may subsequently activate the error-prone DNA repair and non-homologous recombination pathways.