We have shown that metastatic oral cancer and metastatic prostate cancer secrete high levels of HSP90-positive EVs and EV-free HSP90, while the targeted knockdown of HSP90α, HSP90β, and their cochaperone CDC37 powerfully diminish EV-driven malignancy events and macrophage M2 polarization in oral cancer [17,19,20,30]. Here, HSP90AA1 is linked to metastatic prostate carcinoma.