FLT3 and cancer: The class III RTK family includes platelet-derived growth factor receptor (PDGFR)-α/β, c-KIT, colony stimulating factor 1 receptor (CSF1R), and FMS-like tyrosine kinase 3 (FLT-3), which play critical roles in the proliferation, differentiation, angiogenesis, and malignancy of various types of human cancers [5].