Despite the initial enthusiasm surrounding the cloning of p63 as a homologue of p53 tumour suppressor gene, mutational analyses have demonstrated rare p63 mutations (<4%) in a large number of human primary tumours including urothelial tumours (Osada et al, 1998; Hagiwara et al, 1999; Sunahara et al, 1999; Park et al, 2000). The gene discussed is TP63; the disease is neoplasm.