Research investigations in colorectal cancer have demonstrated that cancer-associated fibroblasts (CAFs) secrete hepatocyte growth factor (HGF), osteopontin (also known as secreted phosphoprotein 1; SPP1), and stroma-derived factor 1α (SDF-1α or CXCL12), thereby augmenting cancer cell stemness through the activation of the Wnt pathway [109, 110]. Here, SPP1 is linked to colorectal cancer.