The PDGFRA (platelet-derived growth factor receptor alpha) gene encodes a transmem-brane glycoprotein that belongs to the type III receptor tyrosine kinase family and has a key role in a variety of cellular processes. 

PDGFRA gene rearrangements are rarely genetic events detected in myeloid and lymphoid neoplasms. These rearrangements most frequently occur in chronic eosinophilic leukemia (CEL), but can be also detected in acute myeloid leukemia (AML), and T-lymphoblastic leukemia/lymphoma (T-ALL). The most common gene fusion partner for PDGFRA is the FIP1-like 1 (FIP1L1) gene caused by an 800 kb interstitial deletion on chromosome 4q12. The result of this deletion is the loss of the CHIC2 gene and the fusion of the 5' end of the FIP1L1 gene with the 3' end of the PDGFRA gene. Although FIP1L1 is the most common fusion partner of PDGFRA, five other partner genes have been identified, including BCR, ETV6, KIF5B, STRN, and CDK5RAP2. Identification of patients harboring a PDGFRA rearrangement is important as these patients respond very well to a targeted therapy with imatinib. In CEL patients harboring a PDGFRA-FIP1L1 fusion a good response to other tyrosine kinase inhibitors like dastinib, nilotinib, sorafenib, and midostaurin could be demonstrated. Hence, detection of PDGFRA rearrangements by Fluorescence in situ Hybridization (FISH) may be of diagnostic and predictive relevance.