Tumor-derived exosome, a secreted membrane vesicle produced from inward budding of endosomal membrane, is generally considered as a promising source of tumor vaccine since it contains abundant immune regulatory proteins including MHCI [125], MHCII [126], and heat shock protein 70 [127] and various tumor rejection antigens including gp96, Her2, and tyrosinase related protein (TRP) [128]. Here, HSP90B1 is linked to neoplasm.