SMAD7 and prostate cancer: The exact biological mechanism for the interaction between polyps and SMAD7 is unknown; however, a recent study in prostate cancer cells found that SMAD7 can interact with adenomatous polyposis coli (APC) protein in linking the TGF-β type I receptors to the microtubule system to promote cell migration [32], indicating a possible role of SMAD7 in the progression from adenomatous polyps to CRCs.