ARID1A and renal pelvis/ureter urothelial carcinoma: In UTUC, the most prevalently altered genes were TP53 (38%), KMT2D (23%), and FGFR3 (17%) in clinical stage I/II tumors, while TP53 (51%), KMT2D (26%), and ARID1A (21%) in clinical stage III/IV tumors (Figure 4A).