Myeloid Neoplasm with PCM1-PDGFRB Transcript Responded to Low-Dose Imatinib: One Case Report with Literature Review.

Through an RNA-seq analysis of an adult patient with unclassifiable myelodysplastic/myeloproliferative neoplasms (MDS/MPN-U), we identified a rare PDGFRB fusion partner gene, PCM1. Conventional chromosome karyotype analysis showed abnormal clones of t(5;8)(q32;p22), and fluorescence in situ hybridization (FISH) confirmed rearrangement of the PDGFRB gene. Reverse transcription PCR (RT-PCR) and Sanger sequencing further confirmed that exon 30 of the PCM1 gene was fused with exon 11 of PDGFRB in frame, and the fusion event was accompanied by a 14 bp deletion of exon 11 of PDGFRB. After low-dose imatinib treatment, the patient achieved complete molecular remission. This study not only broadens the understanding of myeloid/lymphoid neoplasms with PDGFRB rearrangement but also reflects the vital role of RNA-seq in identifying PDGFRB rearrangements.