This forms a CCR2-MMP9-CCL2+ feedback loop between TAMs and the cancer cells, which significantly contributes to resistance to chemotherapeutic drugs (e.g., cisplatin) due to the expression of ZEB1 by both cancer and stroma cells (TAMs) (Fig. 2).260 Targeting ZEB1 in cancer cells is currently being considered in clinical trials. The gene discussed is MMP9; the disease is cancer.