1. Expression of a novel type of KMT2A/EPS15 fusion transcript in FLT3 mutation-positive B-lymphoblastic leukemia with t(1;11)(p32;q23)
- Author
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Hisayuki Matsumoto, Kimikazu Yakushijin, Yu Mizutani, Marika Okuni-Watanabe, Hironobu Minami, Hiroshi Matsuoka, Katsuya Yamamoto, Yoshiharu Miyata, Akihito Kitao, Jun Saegusa, Hideaki Goto, and Ako Higashime
- Subjects
Cancer Research ,Oncogene Proteins, Fusion ,CD33 ,Bone Marrow Cells ,Chromosomal translocation ,Translocation, Genetic ,Fusion gene ,03 medical and health sciences ,Exon ,Fatal Outcome ,0302 clinical medicine ,Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ,hemic and lymphatic diseases ,Genetics ,Humans ,Amino Acid Sequence ,RNA, Messenger ,B-lymphoblastic leukemia ,Cell Shape ,Molecular Biology ,Aged ,KMT2A/EPS15 ,Base Sequence ,biology ,Chromosomes, Human, Pair 11 ,Lymphoblast ,Myeloid leukemia ,Molecular biology ,KMT2A ,fms-Like Tyrosine Kinase 3 ,Fusion transcript ,Chromosomes, Human, Pair 1 ,030220 oncology & carcinogenesis ,Mutation ,biology.protein ,Female ,FLT3 mutation - Abstract
The t(1;11)(p32;q23) translocation is a rare but recurrent cytogenetic aberration in acute myeloid leukemia (AML) and B-cell acute lymphoblastic leukemia (B-ALL). This translocation was initially shown to form a fusion gene between KMT2A exon 8 at 11q23 and EPS15 exon 2 at 1p32 in AML. Activating mutations of FLT3 are frequently found in AML but are very rare in ALL. Here, we describe a 75-year old woman who was diagnosed with B-ALL since her bone marrow was made up of 98.2% lymphoblasts. These blasts were positive for CD19, CD22, CD79a, CD13, and CD33 but negative for CD10 and myeloperoxidase. The karyotype by G-banding and spectral karyotyping was 46,XX,t(1;11)(p32;q23). Expression of KMT2A/EPS15 and reciprocal EPS15/KMT2A fusion transcripts were shown: KMT2A exon 8 was in-frame fused to EPS15 exon 12, indicating that this fusion transcript was a novel type. Considering three reported B-ALL cases, EPS15 breakpoints were markedly different between AML (exon 2) and B-ALL (exons 10-12). Furthermore, an uncommon type of FLT3 mutation in the juxtamembrane domain was detected: in-frame 4-bp deletion and 10-bp insertion. Accordingly, our results indicate that the novel type of KMT2A/EPS15 fusion transcript and FLT3 mutation may cooperate in the pathogenesis of adult B-ALL as class II and class I mutations, respectively.
- Published
- 2021