EP300 and renal pelvis/ureter urothelial carcinoma: Of note, the frequency of FGFR3 (17.02% vs. 2.38%) and EP300 (14.89% vs. 4.76%) was significantly higher in UTUC patients with low clinical stage, along with a higher prevalence of GAs in RTK/RAS pathway (38.30% vs. 21.43%, Figure 4B).