A case of pediatric B-Lymphoblastic leukemia presenting with a t(9;12)(p24;q11.2) involving JAK2 and concomitant MLL rearrangement with apparent insertion at 6q27

Biomarker Research

Carlos A Tirado³  David Shabsovich¹  Matthew DeNicola³  Dinesh Rao³  Lynn Yang³  Rolando Garcia²  Nagesh Rao³ 

[1] Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA

[2] UT Southwestern Medical Center Department of Pathology, Dallas, Texas, USA

[3] Department of Pathology and Laboratory Medicine, David Geffen UCLA School of Medicine, Los Angeles, CA 90095, USA

关键词: B-ALL;    FISH;    MLL;    JAK2;   

Others  :  791839
DOI  :  10.1186/2050-7771-1-31

 received in 2013-11-07, accepted in 2013-11-08,  发布年份 2013

【 摘 要 】

Background

B-cell acute lymphoblastic leukemia (B-ALL) is the most common malignancy in pediatric patients and the leading cause of cancer-related death in children and young adults. Translocations of 9p24 involving JAK2 (9p24) and gain-of-function mutations of JAK2 with subsequent activation of the JAK2 kinase have been described in several hematological malignancies including B-ALL. However, rearrangements involving JAK2 are rare in B-ALL as only few cases have been described in the literature.

Findings

Herein, we present a case of pediatric B-ALL whose conventional cytogenetics revealed an abnormal karyotype with a reciprocal translocation involving 9p24 (JAK2) and 12p11.2. Fluorescence in situ hybridization (FISH) studies using the RP11-927H16 Spectrum Green JAK2 probe on previously G-banded metaphases confirmed the involvement of JAK2 in this rearrangement. Further FISH studies on the same previously G-banded metaphases using the LSI MLL probe helped to characterize an insertion of MLL into 6q27 as an additional abnormality in this karyotype. FISH studies performed on interphase nuclei also revealed an abnormal clone with MLL rearrangements in 23.6% of the nuclei examined as well as an abnormal clonal population with a deletion of the 5'IGH@ region in 88.3% of the nuclei examined.

Conclusions

Rearrangements of 9p24 can result in constitutive activation of JAK2, and have been observed in B-ALL. Rearrangements of the MLL gene have also been described extensively in B-ALL. However, rearrangements of MLL with a partner at 6q27 and in conjunction with a translocation involving JAK2 have not been previously described. This case pinpoints the importance of FISH and conventional cytogenetics to characterize complex rearrangements in which JAK2 and MLL are involved. The therapeutic targeting of JAK2 and MLL in cases like this may be prognostically beneficial.

【 授权许可】

   
2013 Tirado et al.; licensee BioMed Central Ltd.

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