First isolated from the T-leukemia cell line J6, FAT1 is located on human chromosome 4q35.2, consists of 27 exons, and encodes proteins with a single transmembrane domain, 34 extracellular cadherin repeats, and laminin G-like and epidermal growth factor (EGF)-like domains (5, 6). This evidence concerns the gene EGF and leukemia.