Lab Med Online.  2019 Oct;9(4):258-262. 10.3343/lmo.2019.9.4.258.

Acute Monoblastic Leukemia with t(11;17)(q23;q21): Fusion of the KMT2A(MLL) and MLLT6(AF17) Genes

• Park CG
• Mun SH
• Lee AJ
• Jeon CH
• Suh HS
• Kim SG

• KMID: 2458689
• DOI: http://doi.org/10.3343/lmo.2019.9.4.258

Abstract

The KMT2A (formerly MLL) gene is associated with at least 10% of all cases of acute leukemia. More than 80 translocation partner genes of KMT2A have been discovered to date, six of which have been identified on the long arm of chromosome 17. Among these, the MLLT6 (formerly AF17) gene is located at 17q12 and fuses with the KMT2A gene in rare cases of acute leukemia. We report here a case of AML with a KMT2A/MLLT6 fusion that was confirmed using molecular genetic methods. According to a literature review, this is the first reported case of AML with a KMT2A/MLLT6 fusion in Korea.

Keyword

Acute monoblastic leukemia; AML; KMT2A; MLL; MLLT6

MeSH Terms

Arm
Chromosomes, Human, Pair 17
Korea
Leukemia
Leukemia, Monocytic, Acute*
Molecular Biology

Figure

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  Fig. 1 Peripheral blood and bone marrow smears of the patient. (A) A peripheral blood smear shows monoblasts with abundant cytoplasm and prominent nucleoli (Wright stain, ×400). (B) A bone marrow aspiration smear shows uniform proliferation of monoblasts which have round/folded nuclear and abundant cytoplasm (Wright stain, ×400).

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  Fig. 2 Chromosomal analysis showed the translocation, 46,XX,t(11;17)(q23;q21)[19]/46,XX[1] (trypsin-Giemsa G-band).

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  Fig. 3 (A) A reverse transcription-PCR assay shows a band in the second lane (M2). (B) Split-out image shows a band (approximately 600 base pairs) in lane 2B, which indicates KMT2A/MLLT6 fusion transcripts.

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  Fig. 4 FISH analysis of a follow-up bone marrow sample with dual color (green and red) probes of KMT2A. The circled cell shows one yellow, one green and one red signal, which indicate KMT2A rearrangement (in 5/200 interphase cells, reference range: < 2%).

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