Different soluble mediators may exert additive/synergistic effects on the induction of tumor cell EMT, as has been demonstrated with TGF-β and TNF-α in lung cancer cells [95]; TNF-α, IL-1β, and IL-6 in renal cell carcinoma (RCC) cells [85]; IL-6 and CCL2 in NSCLC cells [88]; TGF-β, IL-6, and TNF-α in inflammatory breast cancer cells [76]; IL-6 and EGF in ovarian carcinoma cells [90]; and IL-6 and TGF-β in NSCLC cells [103]. Here, CCL2 is linked to renal cell carcinoma.