Ege Cubuk, Anindita Ghosh, Pamela E Camacho, Andrea N Marcogliese, Angshumoy Roy, Pulivarthi H Rao, Dolores H Lopez-Terrada, Jennifer Scull, Kevin E Fisher
This case highlights the role of multimodal molecular diagnostics to diagnose and monitor pediatric CML patients with atypical fusion isoforms.
BACKGROUND: Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm typically defined by BCR::ABL1 p210 fusions isoforms.
OBSERVATIONS: An 8-year-old female CML patient harbored a typical t(9;22)(q34;11) Philadelphia chromosome and BCR::ABL1 fusion by conventional karyotyping and FISH but lacked BCR::ABL1 p210 fusion transcripts by RT-PCR. Targeted next-generation sequencing (NGS) revealed BCR::SPECC1L::ABL1 fusion transcripts predicted to encode an in-frame BCR-exon-8::SPECC1L-exon-4::ABL1-exon-2 fusion protein retaining the tyrosine kinase domain. FISH and NGS were used for therapeutic imatinib monitoring given this atypical isoform.
CONCLUSIONS: This case highlights the role of multimodal molecular diagnostics to diagnose and monitor pediatric CML patients with atypical fusion isoforms.