CCL2 and cancer: Tumor-derived C–C motif chemokine ligand 2 (CCL2) binds to CCR2+/Ly6Chi endothelial cells to increase vascular permeability and recruit inflammatory monocytes in a p38/MAPK-dependent manner, thereby promoting the extravasation and seeding of metastatic cancer cells (Roblek et al., 2016; Roblek et al., 2019).