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

Fluorescence in situ hybridization (FISH) analysis of the pediatric T-ALL using a home-made, dual color fusion probe for the detection of the chimeric gene histone-lysine N-methyltransferase 2A - elongation factor for RNA polymerase II (KMT2A-ELL) gene. (A) Ideogram of the chromosome 11 showing the mapping position of the KMT2A gene at 11q23.3 (vertical green line). (B) Diagram showing the FISH probes RP11-770J1 and RP11-861M13 for KMT2A. The neighboring genes are also shown. (C) Ideogram of chromosome 19 showing the mapping position of the ELL gene at 19p13.11 (red box). (D) Diagram showing the FISH probes CH17-258D2, CH17-343F16, CH17-413G9, and CH17-338M17 for ELL. The neighboring genes in this region are also shown. (E) FISH results with the KMT2A (green signal) and ELL (red signal) probes on interphase nuclei. A nucleus with a yellow signal for the KMT2A-ELL fusion, a red signal for normal ELL, a green signal for normal KMT2A, and a green signal corresponding to the 3’end of the KMT2A which was moved to der(19). (F) FISH results with the KMT2A (green signal) and ELL (red signal) probes on a metaphase spread. A KMT2A-ELL fusion yellow signal on der(11), a normal KMT2A green signal on chromosome 11, a KMT2A green signal on der(19), and a normal ELL red signal on chromosome 19 are shown.