PDGFRBrearranged

PDGFRB rearranged refers to a group of hematologic neoplasms in which the PDGFRB gene, encoding the platelet-derived growth factor receptor beta, is involved in chromosomal rearrangements. These fusion events create constitutively active receptor tyrosine kinases that drive proliferation of myeloid and sometimes lymphoid cells, frequently accompanied by eosinophilia. The spectrum includes a variety of fusion partners, such as FIP1L1-PDGFRB and ETV6-PDGFRB, among others, with the exact partner influencing disease presentation and behavior.

Clinical features commonly include persistent eosinophilia and signs related to myeloid or mixed lineage proliferation. Patients may present with fatigue, splenomegaly, anemia, thrombocytopenia, or organ involvement due to eosinophilic infiltration. The abnormal clone can be indolent or progress to a myeloproliferative phenotype, and some cases may evolve over time.

Diagnosis relies on detection of PDGFRB rearrangements in blood or bone marrow. Cytogenetic analysis, fluorescence in situ hybridization (FISH), and reverse transcription polymerase chain reaction (RT-PCR) assays identify rearrangements or fusion transcripts. The World Health Organization classifies these conditions under myeloid/lymphoid neoplasms with eosinophilia and PDGF receptor gene rearrangements, alongside those involving PDGFRA and FGFR1.

Treatment with tyrosine kinase inhibitors, particularly imatinib, is central and often highly effective, even at low doses. Responses can include hematologic and molecular remission. Some patients with resistance or intolerance may benefit from alternative TKIs such as dasatinib, ponatinib, or nilotinib, depending on the fusion partner and disease course. Prognosis is generally favorable with targeted therapy, though outcomes vary by partner gene and disease severity.