In gastric cancer, circMAPK1 exerts suppressive function through encoding a novel protein MAPK1-109aa, which competitively binds to MEK1 and then decreases the phosphorylation of MAPK1, thus inactivating MAPK1 and the downstream molecules in MAPK signaling pathway [207]; circRNA hsa_circ_0044301 promotes cell proliferation by acting as hsa-miR-188-5p sponge to upregulate DAXX (ERK1/2) expression and MAPK signaling pathway [208]; hsa-circ-0052001 promotes cell proliferation and invasion via sponging hsa-miR-608 to regulate the MAPK pathway [209] (Fig. 9). Here, MAPK1 is linked to gastric cancer.