HSP90AA1 and gastrointestinal stromal tumor: TAS-116 is the representative HSP90α/β selective inhibitor, derived from SNX2112,430,431 which realized the affinity for HSP90α/β (Ki = 21.3/34.7 nM), over 1400-folds selective compared to GRP94 and TRAP-1.432,433 Notably, TAS-116 (trade name Jeselhy) have been approved by Japan in 2022, for the treatment of chemotherapy-resistant GIST (Table 2).434 The first approval represents significant progress in the development of targeting molecular chaperones as therapeutic drugs.