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Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia.

ABSTRACT: Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathway-activating mutations in the neuroblastoma RAS viral oncogene homolog (NRAS), kirsten rat sarcoma viral oncogene homolog (KRAS), and protein tyrosine phosphatase, nonreceptor type 11 (PTPN11) genes were present in 24 of 55 (44%) cases in our series. Interestingly, some leukemias showed retention or emergence of RAS mutant clones at relapse, whereas in others RAS mutant clones present at diagnosis were replaced by RAS wild-type populations, supporting a role for both positive and negative selection evolutionary pressures in clonal evolution of RAS-mutant leukemia. Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts. These results highlight the central role of chemotherapy-driven selection as a central mechanism of leukemia clonal evolution in relapsed ALL, and demonstrate a previously unrecognized dual role of RAS mutations as drivers of both sensitivity and resistance to chemotherapy.

SUBMITTER: Oshima K

PROVIDER: S-EPMC5056035 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia.

Oshima Koichi K Khiabanian Hossein H da Silva-Almeida Ana C AC Tzoneva Gannie G Abate Francesco F Ambesi-Impiombato Alberto A Sanchez-Martin Marta M Carpenter Zachary Z Penson Alex A Perez-Garcia Arianne A Eckert Cornelia C Nicolas Concepción C Balbin Milagros M Sulis Maria Luisa ML Kato Motohiro M Koh Katsuyoshi K Paganin Maddalena M Basso Giuseppe G Gastier-Foster Julie M JM Devidas Meenakshi M Loh Mignon L ML Kirschner-Schwabe Renate R Palomero Teresa T Rabadan Raul R Ferrando Adolfo A AA

Proceedings of the National Academy of Sciences of the United States of America 20160921 40

Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathw ...[more]

PMID: 27655895

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Project description:Multiple Myeloma (MM) arises from malignant transformation and deregulated proliferation of clonal plasma cells (PCs) harbouring heterogeneous molecular anomalies. The effect of evolving mutations on clone fitness and their cellular prevalence shapes the progressing myeloma genome and impacts clinical outcomes. Although clonal heterogeneity in MM is well established, which subclonal mutations emerge/persist/perish with progression in MM and which of these can be targeted therapeutically remains an open question. In line with this, we have sequenced pairwise whole exomes of 62 MM patients collected at two time points, i.e., at diagnosis and on progression. Somatic variants were called using a novel ensemble approach where a consensus was deduced from four variant callers (Illumina's Dragen, Strelka2, SomaticSniper and SpeedSeq) and actionable/druggable gene targets were identified. A marked intraclonal heterogeneity was observed. Branching evolution was observed among 72.58% patients, of whom 64.51% had low TMBs (<10) and 61.29% had 2 or more founder clones. The hypermutator patients (with high TMB levels ≥10 to ≤100) showed a significant decrease in their TMBs from diagnosis (median TMB 77.11) to progression (median TMB 31.22). A distinct temporal fall in subclonal driver mutations was identified recurrently across diagnosis to progression e.g., in PABPC1, BRAF, KRAS, CR1, DIS3 and ATM genes in 3 or more patients suggesting such patients could be treated early with target specific drugs like Vemurafenib/Cobimetinib. An analogous rise in driver mutations was observed in KMT2C, FOXD4L1, SP140, NRAS and other genes. A few drivers such as FAT4, IGLL5 and CDKN1A retained consistent distribution patterns at two time points. These findings are clinically relevant and point at consideration of evaluating multi time point subclonal mutational landscapes for designing better risk stratification strategies and tailoring time to time risk adapted combination therapies in future.

Dataset Information

Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia.

Publications

Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia.

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