CD44 and colorectal carcinoma: Upon exploring the role of CD44v6 in CRC progression, several anti-CD44v6 strategies have been developed; several of these strategies aim to antagonize the interaction between HA and CD44v6 by using the soluble CD44 ectodomain to block HA binding, by using the α-CD44-HABD mAb to block the HA-binding epitope on the CD44 ectodomain, or by using the small fragment of HA (sHA), which inhibits the binding of HA to the CD44 ectodomain (Fig. 5a).