Molecular diagnosis and targeted therapy of a pediatric chronic eosinophilic leukemia patient carrying TPM3-PDGFRB fusion.

We report a rare pediatric chronic eosinophilic leukemia (CEL) case of an 8-year-old male whose leukemic cells carried t(1; 5)(q21; q33) chromosomal abnormality. Sequencing analysis confirmed a TPM3-PDGFRB fusion, and the breakpoint was the same as adult patient. Targeted therapy with imatinib induced a rapid hematologic response and reduction of TPM3-PDGFRB transcripts as monitored by reverse transcription real-time PCR (RT-qPCR). We then established an RT-qPCR assay applicable to detection of all possible PDGFRB fusions and also validated this assay in the patient. These data should provide a valuable reference for management of pediatric CEL.