HSP90AA1 and digestive system neoplasm: Recently, the first Hsp90 inhibitor, 3-ethyl-4-[3-(1-methylethyl)-4-[4-(1-methyl-1H-pyrazol-4-yl)-1H-imidazol-1-yl]-1H-pyrazolo[3,4-b]pyridin-1-yl]-benzamide (TAS-116), was approved for gastrointestinal tumors in Japan (52).