IL6 and cancer: Moreover, monocytes are able to release monocyte chemo-attractant protein (MCP-1)-1 upon stimulation and mediate tumor-associated macrophage infiltration in solid tumors, which could produce a variety of chemokines such as TGF-â, TNF-á, IL-1 and IL-6 to promote tumorigenesis, angiogenesis and distant metastasis of malignant tumors [48], [49].