TP63 and neoplasm: Urine‐derived tubuloids were positive for paired‐box gene 8 (PAX8) and negative for tumour protein p63 (Fig 6A), confirming that these structures indeed consisted of kidney epithelium (PAX8+/TP63−) and not urothelium (PAX8−/TP63+) (Saito et al, 2006; Albadine et al, 2010).