p53, p63 and p73 make a family of transcription factors that play a vital role in development and cancer All p53 family members have more than one promoter producing Transactivating (TA) and Dominant Negative (Delta N) isoforms and their mRNAs are subjected to extensive splicing at 3' end to produce multiple protein products p53 is usually inactivated by point mutations during tumorigenesis, whereas the expression levels and p63 and p73 are modulated to give tumor cells a selective advantage. In this study, aiming to find novel targets of the p53 family members, we identified FGFR3 as a gene transcriptionally controlled by p63 and p73 FGFR3 has been implicated in development and tumor biology as activating mutations of this gene was described in skeletal disorders, non-invasive skin conditions and superficial bladder cancers We found that TAp73,TAp63 and Delta Np63 was capable of inducing FGFR3 siRNA mediated downregulation of Delta Np63 decreased endogenous FGFR3 protein levels Our findings of this new link between p53 family proteins and FGER3 may help understanding the transition of superficial bladder cancers to an invasive phenotype (C) 2010 Elsevier Inc All rights reserved