PDCD4 and metastatic colorectal cancer: In addition, ABDH5 impairs colon cancer stemness [37]; PDCD4 is a well-known tumor suppressor in CRC [38] and it represses stemness of adipose-derived stem cells [39], gastric [40] and cervical cancer cells [41]; GPA33 is a cell surface antigen expressed across a panel of CSC derived from various stages of CRC, in addition to exhibiting 100% penetrance across over 50 primary and metastatic colorectal cancer specimens, and its application as a therapeutic target is in progress [42,43].