17-DMAG is an inhibitor of HSP90 that exhibits neuroprotective, anticancer chemotherapeutic, and antiviral activities. In animal models of Machado-Joseph disease, 17-DMAG increases levels of beclin-1 and LC3-11, inducing autophagy and improving motor dysfunction. In neuroblastoma cells, this compound exerts effects on anaplastic lymphoma kinase (ALK) and N-Myc, inducing cell cycle arrest and apoptosis. Additionally, 17-DMAG inhibits cell growth and induces apoptosis in adult T-cell leukemia (ATL) cells. In animal models with ATL xenografts, 17-DMAG inhibits metastasis and improves survival rates. 17-DMAG also prevents viral production by human T-lymphocytic virus type-1. In separate models, 17-DMAG decreases expression of conserved herpesvirus protein kinases and suppresses viral growth.