To further clarify the role of PI3K/AKT in hsa_circ_0000520 inhibition of Herceptin resistance in gastric cancer, we used IGF‐1 (an activator of PI3K/AKT) to treat NCI‐N87R cells with hsa_circ_0000520 transfection and Herceptin treatment. Here, IGF1 is linked to gastric cancer.