Four of four cell lines with high HR23b expression were sensitive to vorinostat, whereas none of the four relatively low HR23b expressing lines were sensitive...The overall expression level of HR23b comparing low, moderate and high HR23b expression was significantly associated with sensitivity to HDACi for vorinostat (p = 0.016) but not for belinostat, mocetinostat and entinostat (p = 0.125, p = 0.813 and p = 0.471, respectively; Fisher's exact tests).