SIGLEC1 and glioblastoma: Other adhesion proteins are demonstrated to play a role in the capture of exosomes, including CD169 (sialoadhesin) on macrophages [18], and heparin sulfate proteoglycans on both U-87 MG glioblastoma cells [37] and 293T human embryonic kidney cells [38], while the latter may also bind cytotoxic and/or helper T cells.