Roughly 20 different Hsp90 inhibitors have been, or are currently, in clinical trials (Li and Luo, 2023) and of these, only one, TAS-116/pimitespib, has gained approval for the treatment of gastrointestinal stromal tumours in Japan (Hoy, 2022; Teranishi et al., 2023a; Teranishi et al., 2023b; Doi et al., 2023). This evidence concerns the gene HSP90AB1 and gastrointestinal stromal tumor.