The FAT1 mutation in NB63R4 was acquired during relapse, while the FAT1 mutation in NB67R5 was present at the subclonal level with a 2% variant allele fraction in the primary tumor but increasing in relapse (i.e., a 15% variant allele fraction), indicating clonal expansion (Supplemental Table 3 and Supplemental Fig. 2). This evidence concerns the gene FAT1 and neoplasm.