SMAD2 and colorectal carcinoma: Cai et al. [71] demonstrated in CT26 CRC cell line–derived xenografts that the injection of TAMs into the tumor site significantly increased the number of CRPM nodules and total lung weight, a process dependent on TAM-derived TGF-β secretion and the induction of EMT through the modulation of the Smad2/3/4–Snail–E-cadherin pathway.