The diagnosis of CDCK was supported when PAX8+/p63−, the sensitivity and specificity were 85.7% and 100%, respectively; by contrast, the diagnosis of UTUC was supported when PAX8−/p63+, the sensitivity and specificity were 88.2% and 100%, respectively. The gene discussed is PAX8; the disease is renal pelvis/ureter urothelial carcinoma.