In an attempt to understand the mechanisms that underlie tumour pathogenesis in FGFR3 mutant urothelium, we compared the effects of DNA damage caused by OH‐BBN by analysing the levels of γH2AX, p53, p21, and Ki67 (supplementary material, Figure S4), as well as indicators for signalling pathways, including phosphorylation of ERK, AKT, cJUN, and STAT3 (data not shown). Here, FGFR3 is linked to neoplasm.