en ايمونولوژي Immunology پژوهشي Research <p style="text-align: justify;"><strong>Background:</strong> Chronic inflammation and dys-regulation of the immune system mechanisms are now well established as primary triggers of gastric cancer and peptic ulcer disease. Galectin-9 (Gal-9) is a member of the galectin family and known as an inducer of cell aggregation, adhesion and apoptosis. Gal-9 interaction with its main ligand T-cell immunoglobulin and mucin domain protein-3 (Tim-3) leads to the apoptosis of T cells and dys-regulation of the immune responses in different tumors. In the current study, the mRNA expression pattern of Gal-9 was evaluated in gastric biopsies of patients with gastric cancer and peptic ulcer disease.</p> <p style="text-align: justify;"><strong>Methods</strong>: In this case control study, gastric biopsies were obtained from 46 patients with gastric cancer, 44 patients with peptic ulcer disease and 41 cases <em>with non</em><em>-</em><em>ulcer dyspepsia</em> served as controls who underwent endoscopy for evaluation of their gastric problems. Infection with <em>Helicobacter pylori </em>was determined by rapid urease test for all participants and H&E staining for GC patients. Total RNA was extracted from all gastric tissues and used for cDNA synthesis. Relative expression of Gal-9 mRNA was determined by Real-Time PCR using &beta;-actin as a housekeeping gene.</p> <p style="text-align: justify;"><strong>Results: </strong>Gal-9 was similarly expressed in all three studied groups. No statistical difference was found for Gal-9 expression between gastric cancer patients and control group (2^-&Delta;Ct=0.022 <em>vs</em> 0.0144<em>, p</em>=0.30) and also between peptic ulcer and <em>control groups</em> (2^-&Delta;Ct=0.088 <em>vs</em> 0.144, <em>p</em>=0.16). No correlation was found for Gal-9 expression and infection with <em>Helicobacter pylori</em> (2^-&Delta;Ct= 0.1 <em>vs</em> 0.129, <em>p</em>=0.51).</p> <p style="text-align: justify;"><strong>Conclusion:</strong> Similar expression of Gal-9 in gastric tissues from patients with gastric cancer, peptic ulcer and also <em>non</em><em>-</em><em>ulcer dyspepsia</em> individuals suggest no possible role of this molecule on tumorigenesis and immunoregulatory mechanisms of these gastric disorders.</p> Gastric cancer, Peptic ulcer disease, Galectin-9, Helicobacter pylori 1 7 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-869-1&slc_lang=en&sid=1 Mahdieh Naghavi-Alhosseini mahdyiehnaghavi@yahoo.com 10031947532846006184 10031947532846006184 No Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Tarang Taghvaei Tarang_taghvaei@yahoo.com 10031947532846006185 10031947532846006185 No Department of Internal Medicine, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran Hossein Asgarian-Omran asgarianhossein@yahoo.com 10031947532846006186 10031947532846006186 Yes Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran