In colorectal cancer, CD26+ CSCs generated liver metastases following implantation into the mouse cecal wall [134]; in pancreatic cancer, CD133+CXCR4+ CSCs were responsible for metastasis [26] and the overexpression of CXCR4 enhanced the metastatic potential of pancreatic cancer cells [135]. Here, CXCR4 is linked to colorectal cancer.