MAP2K1 and neoplasm: circASAP1 stimulates the expression of mitogen-activated protein kinase 1 (MAPK1) through sponging miR-326 and miR-532-5p, which further activates the ERK1/2 signaling pathway to promote the proliferation and invasion of HCC cells; additionally, MAPK1 de-inhibits colony stimulating factor 1 (CSF-1) and promotes the proliferation and chemotactic migration of tumor-associated macrophages (TAMs), mediating TAM infiltration into the tumor bed, which is benefit for the tumor metastasis (43).