TGFB1 and cancer: ,49 Our study revealed an association between decreased TGF-β signaling and reduced CD44 expression in vitro and in vivo (Figure 6): as well as the utilization of the conventional CD44 expressed by LLC and mouse vascular ECs, the addition of an anti-CD44 antibody or CD44 knockdown successfully inhibited the engraftment of cancer cells onto ECs (Figure 7).