Targeting the tetraspanin CD81 reduces cancer invasion and metastasis

Significance CD81 belongs to the evolutionary conserved tetraspanin family of proteins that form specialized membranal platforms that facilitate a vast array of cellular processes. However, little is known about the consequences of these molecular interactions under normal or pathological conditions. Tetraspanins have no known natural ligands, but ligation by some antibodies induces functional consequences. Here we show that engagement of CD81 with 5A6 halts tumor invasion in vitro and reduces breast cancer metastasis in vivo. Altogether, these finding highlight the role of CD81 in cancer progression.