Our previous preclinical research revealed that subablative RT stimulated bladder cancer cells to secrete C–C motif chemokine receptor 2 (CCL2) [5], which subsequently attracted C–C motif chemokine receptor 2 (CCR2) + myeloid cells and C–C motif chemokine receptor 4 (CCR4) + regulatory T cells (Tregs) to the irradiated tumor microenvironment (TME) [5, 6]. This evidence concerns the gene CCL2 and neoplasm.