Identification of a MYO18A-PDGFRB fusion gene in an eosinophilia-associated atypical myeloproliferative neoplasm with a t(5;17)(q33-34;q11.2).

Chromosomal aberrations of 5q31-33 associated with rearrangements of the platelet-derived growth factor receptor beta (PDGFRB) gene are rare but recurrent in patients with eosinophilia-associated atypical myeloproliferative neoplasms (Eos-MPNs). We used a DNA-based "long-distance inverse PCR" (LDI-PCR) to identify a new MYO18A-PDGFRB fusion gene in an Eos-MPN with associated t(5;17)(q33-34;q11.2). MYO18A is the fourth partner gene after BCR, ETV6 and SPTBN1 that fuses to more than one tyrosine kinase gene. Treatment with imatinib (400 mg/day) led to rapid and sustained complete hematologic, cytogenetic and molecular remission. Patients with PDGFRB fusions genes are excellent candidates for treatment with imatinib; complete cytogenetic and even molecular remissions are common while primary or secondary resistance seems to be very rare.