Thus, alterations in SMAD4 are an important factor affecting the CRC in progression, influencing tumor characteristics by participating in the regulation of multiple biological processes.6 Typically, SMAD4 interacts with other SMAD proteins to facilitate the transduction of TGF-β signals from the cell surface to the nucleus, thereby affecting the expression of target genes. The gene discussed is TGFB1; the disease is colorectal carcinoma.