Table 1.

Known Physiological Roles of CD44 Isoforms

CD44 Isoform	Physiological Role	Role in Cancer	References
CD44s	Regulates cell growth, survival, differentiation, cell-cell interactions, migration, and adhesion	Overexpression promotes metastatic potential and stemness.	[17, 57, 59]
CD44v3	Binds heparin-binding growth factors which can impact receptor tyrosine kinase signaling	Promotes tumor growth, migration, and metastasis in head and neck cancer.	[67, 78, 84]
CD44v6	Binds and sequesters hepatocyte growth factor to activate the receptor tyrosine kinase c-MET.	Promotes metastasis in pancreatic adenocarcinoma, colorectal cancer, and breast cancer.	[80–83]
CD44v8-10	Interacts with xCT glutamate-cysteine transporter to regulate glutathione levels and redox status	Enhances metastatic colonization in lung cancer	[40]