In HP-infected GES-1 cells, FOS silencing inhibited mast cell migration, cytokine secretion, including C-C motif chemokine ligand 2 (CCL2), interleukin-33 (IL-33), and stem cell factor (SCF), as well as histamine release, accompanied by reduced Treg polarization and decreased expression of transforming growth factor-β and forkhead box P3.<h4>Conclusion</h4>FOS silencing inhibited mast cell activation and Treg cell polarization in HP-induced gastritis, suggesting its promising value as an intervention point in HP-driven gastritis. Here, FOS is linked to gastritis.