It is plausible that the downregulation of FGFR3 by quisinostat we observed in this study may be either an FGFR isoform specific (FGFR3 vs. FGFR2) or a cancer type specific (bladder cancer vs. cholangiocarcinoma) effect. This evidence concerns the gene FGFR3 and urinary bladder carcinoma.