BST2 and cancer: As the BST-2 extracellular domain is critical for BST-2-mediated tumorigenesis, including mediating interactions between cancer cells and other components of the tumor microenvironment, promoting cancer cell survival through activation of the BST-2/GRB2/ERK/BIM/Cas3 signaling pathway, and promoting tumor growth and survival6, we designed B49 that binds to the BST-2 extracellular domain and a non-binding Control peptide (Fig. 1A) and then assessed the efficacy of B49 in blocking cancer cell adhesion.