The landscape of somatic mutations in infant MLL-rearranged acute lymphoblastic leukemias.

Infant acute lymphoblastic leukemia (ALL) with MLL rearrangements (MLL-R) represents a distinct leukemia with a poor prognosis. To define its mutational landscape, we performed whole-genome, exome, RNA and targeted DNA sequencing on 65 infants (47 MLL-R and 18 non-MLL-R cases) and 20 older children (MLL-R cases) with leukemia. Our data show that infant MLL-R ALL has one of the lowest frequencies of somatic mutations of any sequenced cancer, with the predominant leukemic clone carrying a mean of 1.3 non-silent mutations. Despite this paucity of mutations, we detected activating mutations in kinase-PI3K-RAS signaling pathway components in 47% of cases. Surprisingly, these mutations were often subclonal and were frequently lost at relapse. In contrast to infant cases, MLL-R leukemia in older children had more somatic mutations (mean of 6.5 mutations/case versus 1.3 mutations/case, P = 7.15 × 10(-5)) and had frequent mutations (45%) in epigenetic regulators, a category of genes that, with the exception of MLL, was rarely mutated in infant MLL-R ALL

Targetable kinase-activating lesions in Ph-like acute lymphoblastic leukemia

BACKGROUN

Contrasting roles of histone 3 lysine 27 demethylases in acute lymphoblastic leukaemia

T-cell acute lymphoblastic leukaemia (T-ALL) is a haematological malignancy with a dismal overall prognosis, including a relapse rate of up to 25%, mainly because of the lack of non-cytotoxic targeted therapy options. Drugs that target the function of key epigenetic factors have been approved in the context of haematopoietic disorders, and mutations that affect chromatin modulators in a variety of leukaemias have recently been identified; however, ‘epigenetic’ drugs are not currently used for T-ALL treatment. Recently, we described that the polycomb repressive complex 2 (PRC2) has a tumour-suppressor role in T-ALL. Here we delineated the role of the histone 3 lysine 27 (H3K27) demethylases JMJD3 and UTX in T-ALL. We show that JMJD3 is essential for the initiation and maintenance of T-ALL, as it controls important oncogenic gene targets by modulating H3K27 methylation. By contrast, we found that UTX functions as a tumour suppressor and is frequently genetically inactivated in T-ALL. Moreover, we demonstrated that the small molecule inhibitor GSKJ4 (ref. 5) affects T-ALL growth, by targeting JMJD3 activity. These findings show that two proteins with a similar enzymatic function can have opposing roles in the context of the same disease, paving the way for treating haematopoietic malignancies with a new category of epigenetic inhibitors.National Institutes of Health (U.S.) (Grant R37-HD04502

Outcomes of children with BCR-ABL1-like acute lymphoblastic leukemia treated with risk-directed therapy based on the levels of minimal residual disease

Abstract not availableKathryn G. Roberts, Deqing Pei, Dario Campana, Debbie Payne-Turner, Yongjin Li, Cheng Cheng, John T. Sandlund, Sima Jeha, John Easton, Jared Becksfort, Jinghui Zhang, Elaine Coustan-Smith, Susana C. Raimondi, Wing H. Leung, Mary V. Relling, William E. Evans, James R. Downing, Charles G. Mullighan, and Ching-Hon Pu

Somatic histone H3 alterations in pediatric diffuse intrinsic pontine gliomas and non-brainstem glioblastomas

To identify somatic mutations in pediatric diffuse intrinsic pontine glioma (DIPG), we performed whole-genome sequencing of DNA from seven DIPGs and matched germline tissue and targeted sequencing of an additional 43 DIPGs and 36 non-brainstem pediatric glioblastomas (non-BS-PGs). We found that 78% of DIPGs and 22% of non-BS-PGs contained a mutation in H3F3A, encoding histone H3.3, or in the related HIST1H3B, encoding histone H3.1, that caused a p.Lys27Met amino acid substitution in each protein. An additional 14% of non-BS-PGs had somatic mutations in H3F3A causing a p.Gly34Arg alteration.Gang Wu, Alberto Broniscer, Troy A McEachron, Charles Lu, Barbara S Paugh, Jared Becksfort, Chunxu Qu, Li Ding, Robert Huether, Matthew Parker, Junyuan Zhang, Amar Gajjar, Michael A Dyer, Charles G Mullighan, Richard J Gilbertson, Elaine R Mardis, Richard K Wilson, James R Downing, David W Ellison, Jinghui Zhang and Suzanne J Bake

The genetic basis of early T-cell precursor acute lymphoblastic leukaemia

Early T-cell precursor acute lymphoblastic leukaemia (ETP ALL) is an aggressive malignancy of unknown genetic basis. We performed whole-genome sequencing of 12 ETP ALL cases and assessed the frequency of the identified somatic mutations in 94 T-cell acute lymphoblastic leukaemia cases. ETP ALL was characterized by activating mutations in genes regulating cytokine receptor and RAS signalling (67% of cases; NRAS, KRAS, FLT3, IL7R, JAK3, JAK1, SH2B3 and BRAF), inactivating lesions disrupting haematopoietic development (58%; GATA3, ETV6, RUNX1, IKZF1 and EP300) and histone-modifying genes (48%; EZH2, EED, SUZ12, SETD2 and EP300). We also identified new targets of recurrent mutation including DNM2, ECT2L and RELN. The mutational spectrum is similar to myeloid tumours, and moreover, the global transcriptional profile of ETP ALL was similar to that of normal and myeloid leukaemia haematopoietic stem cells. These findings suggest that addition of myeloid-directed therapies might improve the poor outcome of ETP ALL.Jinghui Zhang, Li Ding, Linda Holmfeldt, Gang Wu, Sue L. Heatley, Debbie Payne-Turner, John Easton, Xiang Chen, Jianmin Wang, Michael Rusch, Charles Lu, Shann-Ching Chen, Lei Wei, J. Racquel Collins-Underwood, Jing Ma, Kathryn G. Roberts, Stanley B. Pounds, Anatoly Ulyanov, Jared Becksfort, Pankaj Gupta, Robert Huether, Richard W. Kriwacki, Matthew Parker, Daniel J. McGoldrick, David Zhao, Daniel Alford, Stephen Espy, Kiran Chand Bobba, Guangchun Song, Deqing Pei, Cheng Cheng, Stefan Roberts, Michael I. Barbato, Dario Campana, Elaine Coustan-Smith, Sheila A. Shurtleff, Susana C. Raimondi, Maria Kleppe, Jan Cools, Kristin A. Shimano, Michelle L. Hermiston, Sergei Doulatov, Kolja Eppert, Elisa Laurenti, Faiyaz Notta, John E. Dick, Giuseppe Basso, Stephen P. Hunger, Mignon L. Loh, Meenakshi Devidas, Brent Wood, Stuart Winter, Kimberley P. Dunsmore, Robert S. Fulton, Lucinda L. Fulton, Xin Hong, Christopher C. Harris, David J. Dooling, Kerri Ochoa, Kimberly J. Johnson, John C. Obenauer, William E. Evans, Ching-Hon Pui, Clayton W. Naeve, Timothy J. Ley, Elaine R. Mardis, Richard K. Wilson, James R. Downing, Charles G. Mulligha

Targetable kinase-activating lesions in Ph-like acute lymphoblastic leukemia

BACKGROUND: Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is characterized by a gene-expression profile similar to that of BCR-ABL1-positive ALL, alterations of lymphoid transcription factor genes, and a poor outcome. The frequency and spectrum of genetic alterations in Ph-like ALL and its responsiveness to tyrosine kinase inhibition are undefined, especially in adolescents and adults. METHODS: We performed genomic profiling of 1725 patients with precursor B-cell ALL and detailed genomic analysis of 154 patients with Ph-like ALL. We examined the functional effects of fusion proteins and the efficacy of tyrosine kinase inhibitors in mouse pre-B cells and xenografts of human Ph-like ALL. RESULTS: Ph-like ALL increased in frequency from 10% among children with standard-risk ALL to 27% among young adults with ALL and was associated with a poor outcome. Kinase-activating alterations were identified in 91% of patients with Ph-like ALL; rearrangements involving ABL1, ABL2, CRLF2, CSF1R, EPOR, JAK2, NTRK3, PDGFRB, PTK2B, TSLP, or TYK2 and sequence mutations involving FLT3, IL7R, or SH2B3 were most common. Expression of ABL1, ABL2, CSF1R, JAK2, and PDGFRB fusions resulted in cytokine-independent proliferation and activation of phosphorylated STAT5. Cell lines and human leukemic cells expressing ABL1, ABL2, CSF1R, and PDGFRB fusions were sensitive in vitro to dasatinib, EPOR and JAK2 rearrangements were sensitive to ruxolitinib, and the ETV6-NTRK3 fusion was sensitive to crizotinib. CONCLUSIONS: Ph-like ALL was found to be characterized by a range of genomic alterations that activate a limited number of signaling pathways, all of which may be amenable to inhibition with approved tyrosine kinase inhibitors. Trials identifying Ph-like ALL are needed to assess whether adding tyrosine kinase inhibitors to current therapy will improve the survival of patients with this type of leukemia. (Funded by the American Lebanese Syrian Associated Charities and others.).Kathryn G. Roberts ... Charles G. Mullighan ... et al

Contrasting roles of histone 3 lysine 27 demethylases in acute lymphoblastic leukaemia

T-cell acute lymphoblastic leukaemia (T-ALL) is a haematological malignancy with a dismal overall prognosis, including a relapse rate of up to 25%, mainly because of the lack of non-cytotoxic targeted therapy options. Drugs that target the function of key epigenetic factors have been approved in the context of haematopoietic disorders, and mutations that affect chromatin modulators in a variety of leukaemias have recently been identified; however, 'epigenetic' drugs are not currently used for T-ALL treatment. Recently, we described that the polycomb repressive complex 2 (PRC2) has a tumour-suppressor role in T-ALL. Here we delineated the role of the histone 3 lysine 27 (H3K27) demethylases JMJD3 and UTX in T-ALL. We show that JMJD3 is essential for the initiation and maintenance of T-ALL, as it controls important oncogenic gene targets by modulating H3K27 methylation. By contrast, we found that UTX functions as a tumour suppressor and is frequently genetically inactivated in T-ALL. Moreover, we demonstrated that the small molecule inhibitor GSKJ4 (ref. 5) affects T-ALL growth, by targeting JMJD3 activity. These findings show that two proteins with a similar enzymatic function can have opposing roles in the context of the same disease, paving the way for treating haematopoietic malignancies with a new category of epigenetic inhibitors.Panagiotis Ntziachristos, Aristotelis Tsirigos, G. Grant Welstead, Thomas Trimarchi, Sofia Bakogianni, Luyao Xu, Evangelia Loizou, Linda Holmfeldt, Alexandros Strikoudis, Bryan King, Jasper Mullenders, Jared Becksfort, Jelena Nedjic, Elisabeth Paietta, Martin S. Tallman, Jacob M. Rowe, Giovanni Tonon, Takashi Satoh, Laurens Kruidenier, Rab Prinjha, Shizuo Akira, Pieter Van Vlierberghe, Adolfo A. Ferrando, Rudolf Jaenisch, Charles G. Mullighan, Iannis Aifanti

Tyrosine kinome sequencing of pediatric acute lymphoblastic leukemia: a report from the Children's Oncology Group TARGET Project

One recently identified subtype of pediatric B-precursor acute lymphoblastic leukemia (ALL) has been termed BCR-ABL1-like or Ph-like because of similarity of the gene expression profile to BCR-ABL1 positive ALL suggesting the presence of lesions activating tyrosine kinases, frequent alteration of IKZF1, and poor outcome. Prior studies demonstrated that approximately half of these patients had genomic lesions leading to CRLF2 overexpression, with half of such cases harboring somatic mutations in the Janus kinases JAK1 and JAK2. To determine whether mutations in other tyrosine kinases might also occur in ALL, we sequenced the tyrosine kinome and downstream signaling genes in 45 high-risk pediatric ALL cases with either a Ph-like gene expression profile or other alterations suggestive of activated kinase signaling. Aside from JAK mutations and 1 FLT3 mutation, no somatic mutations were found in any other tyrosine kinases, suggesting that alternative mechanisms are responsible for activated kinase signaling in high-risk ALL.Mignon L. Loh, Jinghui Zhang, Richard C. Harvey, Kathryn Roberts, Debbie Payne-Turner, Huining Kang, Gang Wu, Xiang Chen, Jared Becksfort, Michael Edmonson, Kenneth H. Buetow, William L. Carroll, I-Ming Chen, Brent Wood, Michael J. Borowitz, Meenakshi Devidas, Daniela S. Gerhard, Paul Bowman, Eric Larsen, Naomi Winick, Elizabeth Raetz, Malcolm Smith, James R. Downing, Cheryl L. Willman, Charles G. Mullighan, and Stephen P. Hunge

Genetic alterations activating kinase and cytokine Receptor signaling in high-risk acute lymphoblastic leukemia

Genomic profiling has identified a subtype of high-risk B-progenitor acute lymphoblastic leukemia (B-ALL) with alteration of IKZF1, a gene expression profile similar to BCR-ABL1-positive ALL and poor outcome (Ph-like ALL). The genetic alterations that activate kinase signaling in Ph-like ALL are poorly understood. We performed transcriptome and whole genome sequencing on 15 cases of Ph-like ALL and identified rearrangements involving ABL1, JAK2, PDGFRB, CRLF2, and EPOR, activating mutations of IL7R and FLT3, and deletion of SH2B3, which encodes the JAK2-negative regulator LNK. Importantly, several of these alterations induce transformation that is attenuated with tyrosine kinase inhibitors, suggesting the treatment outcome of these patients may be improved with targeted therapy.Kathryn G. Roberts, Ryan D. Morin, Jinghui Zhang, Martin Hirst, Yongjun Zhao, Xiaoping Su, Shann-Ching Chen, Debbie Payne-Turner, Michelle L. Churchman, Richard C. Harvey, Xiang Chen, Corynn Kasap, Chunhua Yan, Jared Becksfort, Richard P. Finney, David T. Teachey, Shannon L. Maude, Kane Tse, Richard Moore, Steven Jones, Karen Mungall, Inanc Birol, Michael N. Edmonson, Ying Hu, Kenneth E. Buetow, I-Ming Chen, William L. Carroll, Lei Wei, Jing Ma, Maria Kleppe, Ross L. Levine, Guillermo Garcia-Manero, Eric Larsen, Neil P. Shah, Meenakshi Devidas, Gregory Reaman, Malcolm Smith, Steven W. Paugh, William E. Evans, Stephan A. Grupp, Sima Jeha, Ching-Hon Pui, Daniela S. Gerhard, James R. Downing, Cheryl L. Willman, Mignon Loh, Stephen P. Hunger, Marco A. Marra, and Charles G. Mulligha