CUX1–PDGFRA: a novel fusion in myeloid/lymphoid neoplasms with eosinophilia

Eosinophilic disorders are a heterogeneous group of neoplastic and non-neoplastic conditions, characterized by increased number of eosinophils in the peripheral blood and sometimes lead to eosinophil-driven organ damage and dysfunction. Myeloid/lymphoid neoplasms with eosinophilia and tyrosine-kinase fusion genes (MLN-TK) is a group of hematologic neoplasms resulting from the formation of abnormal fusion genes that encode constitutively activated tyrosine kinases. The FIP1L1-PDGFRA fusion gene is the most common genetic abnormality detected in MLN-TK and nine rarer PDGFRA partners have also been documented at the time of writing. A novel fusion gene CUX1-PDGFRA was identified in an adult male with myeloid/lymphoid neoplasms with eosinophilia and tyrosine-kinase fusion genes (MLN-TK) through targeted RNA sequencing. This is the eleventh partner gene fusions for PDGFRA in MLN-TK discovered so far. Given the exquisite responsiveness of PDGFRA fusions to imatinib, we recommended imatinib at a dose of 100mg daily to the patient. The therapeutic response and prognosis remains to be further observed.