Through secreting transforming growth factor β1 (TGFB1), TAMs have abilities to upregulate vascular endothelial growth factor (VEGF) and interleukin-6 (IL6), and the latter binds with IL6 receptor on the tumor cell surface to promote CRC proliferation via activating STAT3 (75, 76). Here, TGFB1 is linked to colorectal carcinoma.