Tumor cell lines, such as hepatocellular carcinoma cell line HepG2 and murine leukemia monocytes cell lines, were described to secrete HSPD1, HSPA1A, and HSP90AA1 in exosomes, which augmented the cytolytic activity of natural killer cells, macrophages and mononuclear cells [117,118,119,120]. Here, HSP90AA1 is linked to hepatocellular carcinoma.