FL indicates FLT3 ligand; E, extracellular domain of FLT3; TM, transmembrane domain; JM, juxtamembrane domain; TKD1, tyrosine kinase domain 1; TKD2, tyrosine kinase domain 2; TKI, tyrosine kinase inhibitor; AGP, alpha-1 acid glycoprotein; and FLT3-ITD, FLT3 receptor with internal tandem duplication mutation.