CCL2 and neoplasm: In addition to CSF1 and TGF-β, RT causes tumor cells to overexpress the C-C motif ligand 2 (CCL2) chemokine, which in turn induces the recruitment of inflammatory macrophages expressing the CCL2 receptor (CCR2) to the tumor site; tumor cell recognition and uptake by inflammatory macrophages release anti-inflammatory signals that facilitate tumor tolerance and therefore contribute to the signaling inhibition of effective anti-tumor immune responses [36,43].