<b><i>ETV6/RUNX1</i></b> Rearrangement Identified by RT-PCR without Evidence on FISH

<i>ETV6</i> fusions from insertions of exons 3-5 in pediatric hematologic malignancies

“…An ETV6::RUNX1 fusion cryptic to FISH but detected by RT-PCR, which was designed to amplify any fusion connecting ETV6 exon 5 to RUNX1 exon 3 or exon 4 (including the insertion fusions described here), was previously reported in a pediatric B-ALL, although underlying genomic structure was not determined. 9 Importantly, in the absence of RNA sequencing or RT-PCR, such FISH-negative cases would likely remain unclassified and, in some clinical protocols, may lead to unintended higher risk stratification and more intensive treatment regimens. 3,4 Similarly, although uncommon in pediatric AML, ETV6 rearrangements are important to identify given their association with adverse risk regardless of fusion partner; chromosome 12p abnormalities/ETV6 rearrangements are accordingly an indication in pediatric AML for allogeneic hematopoietic stem cell transplantation in first remission in the current Children's Oncology Group AAML1831 clinical trial (clinicaltrials gov.…”