XCL1 and cancer: Wang et al. illustrated that VEGFA secreted from CRC sites stimulated tumor-associated macrophages to produce chemokine (C-X-C motif) ligand 1 (CXCL1), subsequently mobilizing PMN-MDSCs to the liver via the CXCL1/chemokine (C-X-C motif) receptor 2 (CXCR2) axis, which led to PMN formation and facilitated cancer cell survival in the host organ (Wang et al., 2017).