Rare KMT2A-ELL and Novel ZNF56-KMT2A Fusion Genes in Pediatric T-cell Acute Lymphoblastic Leukemia

Abstract

Background/aim: Previous reports have associated the KMT2A-ELL fusion gene, generated by t(11;19)(q23;p13.1), with acute myeloid leukemia (AML). We herein report a KMT2A-ELL and a novel ZNF56-KMT2A fusion genes in a pediatric T-lineage acute lymphoblastic leukemia (T-ALL).

Materials and methods: Genetic investigations were performed on bone marrow of a 13-year-old boy diagnosed with T-ALL.

Results: A KMT2A-ELL and a novel ZNF56-KMT2A fusion genes were generated on der(11)t(11;19)(q23;p13.1) and der(19)t(11;19)(q23;p13.1), respectively. Exon 20 of KMT2A fused to exon 2 of ELL in KMT2A-ELL chimeric transcript whereas exon 1 of ZNF56 fused to exon 21 of KMT2A in ZNF56-KMT2A transcript. A literature search revealed four more T-ALL patients carrying a KMT2A-ELL fusion. All of them were males aged 11, 11, 17, and 20 years.

Conclusion: KMT2A-ELL fusion is a rare recurrent genetic event in T-ALL with uncertain prognostic implications. The frequency and impact of ZNF56-KMT2A in T-ALL are unknown.

Keywords: ELL; KMT2A; KMT2A-ELL ZNF56-KMT2A; RNA-sequencing; T-cell acute lymphoblastic leukemia; ZNF56; fusion gene; pediatric.