CCL2 and neoplasm: Besides the elevated levels of matrix metalloproteinases (which remodel the tumor extracellular matrix), tumor cells and activated fibroblasts secrete vascular endothelial growth factor (VEGF) and CXCL-family chemokines (e.g., CXCL12 and CCL2), which result in the recruitment of leukocytes and endothelial cells into the tumor microenvironment [3].