In clinical trials, HSP90 inhibitors were reported to be effective against cancers with driver mutation products that are clients of HSP90, such as KIT, EGFR, ALK, HER2 and BRAF.15 Taken together, TAS-116 may be potentially active against TKI-resistant cancers with driver mutations, of which products are clients of HSP90α/β. Here, HSP90AA1 is linked to cancer.