FGFR3 and in situ carcinoma: Activating mutations of FGFR3, which encodes a growth factor receptor of the fibroblast growth factor receptor family, have been shown to be associated mostly with the Ta pathway of tumour progression, as such mutations have been reported in 65% of pTa tumours, less frequently in pT1 (33%) and pT2-4 tumours (22%) and not at all in CIS [4], [8], [9] [Table S1].