The t(4;9)(q11;q33) fuses CEP110 to KIT in a case of acute myeloid leukemia.

KIT is a class III receptor tyrosine kinase (RTK) that has an important role in hemopoiesis, particularly with regard to stem cell maintenance and mast cell development. KIT is normally activated by engagement with its ligand, stem cell factor, but a variety of acquired KIT point mutations have been described in acute myeloid leukemia (AML) and systemic mastocytosis that result in constitutive, ligand-independent activation. In contrast to other related RTKs such as PDGFRA, PDGFRB and FLT3, constitutive activation of KIT by gene fusion has not been described.