Cldn18 is a tight junction protein specifically expressed in gastric epithelial cells and is frequently downregulated in human gastric cancer, while also serving as a target for novel therapeutic approaches including CAR-T cell therapy and antibody-drug conjugates (Oshima et al., 2013; Moraes et al., 2024; Barrett et al., 2024; Jin et al., 2024). The gene discussed is CLDN18; the disease is gastric cancer.