ERBB2 and renal pelvis/ureter urothelial carcinoma: Among common solid tumors, urothelial cancers had the highest frequency of oncogenic and likely oncogenic ERBB2 mutations, with ERBB2 mutations identified in 8.2% (inclusive of both bladder and upper tract urothelial cancer (UTUC) primary sites), 18.2% of which had concurrent ERBB2 amplification.