4q12 rearrangement, CHIC2/F1LP1L1/PDGFRα, platelet-derived growth factor receptor-α
Hypereosinophilia, Mast cell
Fluorescence in situ Hybridization (FISH)
5mL peripheral blood in sodium heparin
3mL bone marrow in sodium heparin
Fixed cytogenetically prepared cells in sterile centrifuge tube with pellet visible in 3:1, Methanol:Acetic Acid
4°C to 25°C during transit, but specimens may be transported on refrigerated gel packs. Do not allow the gel pack to come in contact with the specimen. Do not freeze. Extreme temperatures should be avoided.
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative
An interstitial deletion on chromosome 4q12 resulting in the formation of the FIP1L1-PDGFRα fusion protein is involved in the pathogenesis of imatinib-sensitive chronic eosinophilic leukemia. Chromosomal deletions resulting in the formation of FIP1L1-PDGFRα has been observed in 14% to 60% of patients with hypereosinophilic syndrome. FISH can detect this deletion in either interphase or metaphase cells.