The most frequently mutated genes in the LS-UTUC group were KMT2D, CREBBP, ARID1A, SMARCA4, CIC, FAT1, FGFR3, FOXP1, KMT2C, NOTCH1 and NOTCH3. The gene discussed is FGFR3; the disease is renal pelvis/ureter urothelial carcinoma.