Definition:

Chronic eosinophilic leukemia (CEL) is a chronic myeloproliferative disease of unknown etiology in which a clonal proliferation of eosinophilic precursors results in a persistently elevated number of eosinophils in blood, bone marrow or peripheral tissues. In most patients with CEL (about 60%), eosinophils display PDGFRA-fusion genes and related cytogenetic defects. The most commonly detected oncoprotein is FIP1L1/PDGFRA. FIP1L1-PDGFRA is a constitutively activated tyrosine kinase, which is suggested to induce the proliferation of EoL-1 (The eosinophilic leukemia cell line) cells by inducing c-Myc expression at the mRNA level via ERK and JNK signaling pathways.