To investigate how bladder cancer risk factors might change the clonal landscape of the urothelium, we focused on 15 genes identified previously to be under positive selection in normal bladder10,15 and/or known to frequently drive bladder tumours16,17 and the promoter of the gene encoding TERT, which is mutated in around 70% of bladder tumours18–23. This evidence concerns the gene TERT and urinary bladder cancer.