In this study, we demonstrate that constitutively releasing high levels of extracellular Hsp70 and Hsp90 through EVs is a common feature of diverse types of cachexia-inducing tumor cells, and that tumor cell-released extracellular Hsp70 and Hsp90 stimulate muscle catabolism resulting in muscle wasting. The gene discussed is HSP90AB1; the disease is Cachexia.