FAT3 and nonpapillary renal cell carcinoma: WES analysis showed an increase of mutational load between baseline (81 mutations) and progression (251 mutations), and 32 (39.5%) of the 81 baseline mutations were also found in the re-biopsy (Figure 3), including changes in VHL, BAP1, KMT2C, CSMD3, and FAT3. The re-biopsy revealed additional private mutations in the epigenetic regulators KMT2D (COSM1299437) and KMT2E (COSM1083684) as well as in PBRM1, one of the most frequently mutated genes in ccRCC, which codes for a subunit of the BAF chromatin remodeling complex.