CD44 and neoplasm: On the other hand, ECM degradation has pro-tumor effects, high ECM stiffness promotes tumor growth compared with soft ECM [166], and degradation products bind to CD44 or RHAMM, activation of Ras-MAPK, PI3K-Akt, FAK and other signaling pathways to enhance tumor cell motility [165, 167], it can also activate TGF-β, and it can also activate TGF-β, NF-κb and other signaling to induce epithelial-mesenchymal transition (EMT) of tumor cells, to make them more invasive and migratory [168].