HSP90AB1 and neoplasm: Exosomes include chaperone HSPs (e.g., Hsp60, Hsp70, Hsp84, and Hsp90), major histocompatibility complex (MHC) for antigen presentation and T cell stimulation, apoptosis-linked gene-2 interacting protein X (ALIX) or tumour susceptibility gene 101 for MVB formation, signal transduction proteins, adhesion molecules, cytoskeletal proteins, enzymes, and tetraspanins [57].