Similarly, the protocadherins FAT1 (15%) and FAT3 (12%) were altered not only in early T-ALL (FAT1 23%, FAT3 15%), but were also recurrently mutated - though in a lower frequency - in thymic T-ALL (FAT1 15%, FAT3 13%; Table 1). Here, FAT1 is linked to acute lymphoblastic leukemia.