CLDN18 and gastric cancer: In gastric cancer, ARHGAP26 is fused with claudin-18 gene (CLDN18), and the translated abnormal fusion protein regulates the development of gastric cancer [7–9], while circular RNA ARHGAP26 (circ-ARHGAP26) modulates microRNA through a “sponge” mechanism to affect the progression of gastric cancer [10–12].