HSP90B1 and neoplasm: Moreover, stimulation of both innate and adaptive forms of antitumor immune responses can be achieved through tumor-derived extracellular Hsp70-, Hsp90-, and gp96-peptide complexes that bind receptors on antigen presenting cells (APCs) and deliver tumor-specific antigens to major histocompatibility complex (MHC) class I molecules on the surface of such cells [207, 226–228].