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FIP1L1/PDGFRα 4q12 Gene Rearrangement by FISH

Test Code

F 4Q12

Test Synonyms

4q12 rearrangement, CHIC2/F1LP1L1/PDGFRα, platelet-derived growth factor receptor-α


Hypereosinophilia, Mast cell


Fluorescence in situ Hybridization (FISH)

Turnaround Time

3-5 days

Specimen Requirements

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

Specimen Stability
Blood and bone marrow = 4°C to 25°C, specimens are stable up to 72 hours
Fixed cell pellets are stable for years when stored at -28°C to 15°C
Storage & Handling

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.

Causes for Rejection

Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative

Reference Range

See report


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.

  1. Buitenhuis M et al. (2007). Cancer Res. 67:(8) April 15.