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Infants with KMT2A ‐rearranged acute lymphoblastic leukemia ( KMT2A -r ALL) have a poor prognosis. KMT2A -r ALL overexpresses FLT3, and the FLT3 inhibitor (FLT3i) lestaurtinib potentiates chemotherapy‐induced cytotoxicity in preclinical models. Children’s Oncology Group (COG) AALL0631 tested whether adding lestaurtinib to post‐induction chemotherapy improved event-free survival (EFS). After chemotherapy induction, KMT2A -r infants received either chemotherapy only or chemotherapy plus lestaurtinib. Correlative assays included FLT3i plasma pharmacodynamics (PD), which categorized patients as inhibited or uninhibited, and FLT3i ex vivo sensitivity (EVS), which categorized leukemic blasts as sensitive or resistant. There was no difference in 3-year EFS between patients treated with chemotherapy plus lestaurtinib ( n  = 67, 36 ± 6%) vs. chemotherapy only ( n  = 54, 39 ± 7%, p  = 0.67). However, for the lestaurtinib-treated patients, FLT3i PD and FLT3i EVS significantly correlated with EFS. For FLT3i PD, EFS for inhibited/uninhibited was 59 ± 10%/28 ± 7% ( p  = 0.009) and for FLTi EVS, EFS for sensitive/resistant was 52 ± 8%/5 ± 5% ( p  < 0.001). Seventeen patients were both inhibited and sensitive, with an EFS of 88 ± 8%. Adding lestaurtinib did not improve EFS overall, but patients achieving potent FLT3 inhibition and those whose leukemia blasts were sensitive FLT3-inhibition ex vivo did benefit from the addition of lestaurtinib. Patient selection and PD-guided dose escalation may enhance the efficacy of FLT3 inhibition for KMT2A -r infant ALL.

Adolescent and young adult (AYA) patients 16–30 years old with high-risk acute lymphoblastic leukemia (HR-ALL) have inferior outcomes compared to younger HR-ALL patients. AALL0232 was a Phase 3 randomized Children’s Oncology Group trial for newly diagnosed HR B-ALL (1–30 years). Between 2004 and 2011, 3154 patients enrolled with 3040 eligible and evaluable for induction. AYA patients comprised 20% of patients (16–21 years, n = 551; 22–30 years, n = 46). 5-year event-free survival and overall survival was 65.4 ± 2.2% and 77.4 ± 2.0% for AYA patients compared to 78.1 ± 0.9% and 87.3 ± 0.7% for younger patients (p < 0.0001). Five-year cumulative incidence of relapse was 18.5 ± 1.7% for AYA patients and 13.5 ± 0.7% for younger patients (p = 0.006), largely due to increased marrow relapses (14.0 ± 1.5% versus 9.1 ± 0.6%; p < 0.0001). Additionally, induction failure rate was higher in AYA (7.2 ± 1.1% versus 3.5 ± 0.4%; p < 0.001) and post-induction remission deaths were significantly higher in AYA (5.7 ± 1.0% versus 2.4 ± 0.3%; p < 0.0001). AALL0232 enrolled the largest number of AYA B-ALL patients to date, demonstrating significantly inferior survival and greater rates of treatment-related toxicities compared to younger patients. Although treatment intensification has improved outcomes in younger patients, they have not been associated with the same degree of improvement for older patients.

Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nucleotides, located within the intergenic stretches or overlapping antisense transcripts of protein coding genes. LncRNAs are involved in numerous biological roles including imprinting, epigenetic regulation, apoptosis, and cell cycle. To determine whether lncRNAs are associated with clinical features and recurrent mutations in older patients (aged ≥60 y) with cytogenetically normal (CN) acute myeloid leukemia (AML), we evaluated lncRNA expression in 148 untreated older CN-AML cases using a custom microarray platform. An independent set of 71 untreated older patients with CN-AML was used to validate the outcome scores using RNA sequencing. Distinctive lncRNA profiles were found associated with selected mutations, such as internal tandem duplications in the FLT3 gene ( FLT3 -ITD) and mutations in the NPM1 , CEBPA , IDH2 , ASXL1 , and RUNX1 genes. Using the lncRNAs most associated with event-free survival in a training cohort of 148 older patients with CN-AML, we derived a lncRNA score composed of 48 lncRNAs. Patients with an unfavorable compared with favorable lncRNA score had a lower complete response (CR) rate [ P < 0.001, odds ratio = 0.14, 54% vs. 89%], shorter disease-free survival (DFS) [ P < 0.001, hazard ratio (HR) = 2.88] and overall survival (OS) ( P < 0.001, HR = 2.95). The validation set analyses confirmed these results (CR, P = 0.03; DFS, P = 0.009; OS, P = 0.009). Multivariable analyses for CR, DFS, and OS identified the lncRNA score as an independent marker for outcome. In conclusion, lncRNA expression in AML is closely associated with recurrent mutations. A small subset of lncRNAs is correlated strongly with treatment response and survival. Significance Long noncoding RNAs (lncRNAs) are involved in numerous biological roles including epigenetic regulation, apoptosis, and cell cycle. Whereas lncRNAs contribute to epigenetic gene regulation, metastasis, and prognosis in solid tumors, their role in acute myeloid leukemia (AML) has not been hitherto reported. Here, we show that lncRNA expression profiles are associated with recurrent mutations, clinical features, and outcome in AML. A fraction of these lncRNAs may have a functional role in leukemogenesis. Furthermore, lncRNAs could be used as biomarkers for outcome in AML. The identification of patients likely to achieve complete remission with standard therapy alone, based on lncRNA expression, is a significant advance potentially sparing such patients from other toxicities and focusing investigational approaches on postremission studies.

Charles Mullighan and colleagues report a recurrent rearrangement of CRLF2 in B-progenitor and Down syndrome-associated acute lymphoblastic leukemia. Their genetic and functional evidence indicates that CRLF2 cooperates with activated JAK2 to promote leukemogenesis. Aneuploidy and translocations are hallmarks of B-progenitor acute lymphoblastic leukemia (ALL), but many individuals with this cancer lack recurring chromosomal alterations. Here we report a recurring interstitial deletion of the pseudoautosomal region 1 of chromosomes X and Y in B-progenitor ALL that juxtaposes the first, noncoding exon of P2RY8 with the coding region of CRLF2 . We identified the P2RY8-CRLF2 fusion in 7% of individuals with B-progenitor ALL and 53% of individuals with ALL associated with Down syndrome. CRLF2 alteration was associated with activating JAK mutations, and expression of human P2RY8-CRLF2 together with mutated mouse Jak2 resulted in constitutive Jak-Stat activation and cytokine-independent growth of Ba/F3 cells overexpressing interleukin-7 receptor alpha. Our findings indicate that these two genetic lesions together contribute to leukemogenesis in B-progenitor ALL.

Errors in chromosome segregation during gametogenesis, such as nondisjunction (NDJ) errors, have severe consequences in human reproduction, and a better understanding of their etiology is of fundamental interest in genetics. Mapping NDJ errors to meiotic/mitotic stages typically requires proband-parent comparison, limiting its applicability. Herein, we develop Mis-segregation Error Identification through Hidden Markov Models (MeiHMM), a method for inferring NDJ error stage and crossover events based on only genomic data of trisomic probands. Guided by triallelic genotype/haplotype configurations, MeiHMM discerns the allelic origin at each locus, which informs NDJ error during gamete formation, without identifying the parental origin of the trisomy. In 152 Down syndrome (DS) cases, MeiHMM achieved an accuracy of 96.1% in classifying NDJ errors, with a sensitivity of 91.6% in crossover identification, compared to proband-parents trio analysis. 17% of Meiosis II errors were misclassified as Meiosis I, mainly due to small proximal crossover events. Applying MeiHMM to 509 children with DS-associated childhood leukemia, we demonstrate that NDJ error is associated with the age of disease onset, somatic genomic abnormalities, and prognosis. Thus, MeiHMM is an effective method for trisomic NDJ error classification and crossover identification that can be applied broadly to study the etiology of congenital aneuploidy conditions. The authors report a computational framework for determining the meiotic/mitotic origin of nondisjunction (NDJ) in trisomies without parental data. Applying this to Down syndrome, they uncover links between NDJ error stage and leukemia genomics.

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive Schwann cell-derived neoplasms that occur sporadically or in patients with neurofibromatosis type 1 (NF1). Preclinical research on sporadic MPNSTs has been limited as few cell lines exist. We generated and characterized a new sporadic MPNST cell line, 2XSB, which shares the molecular and genomic features of the parent tumor. These cells have a highly complex karyotype with extensive chromothripsis. 2XSB cells show robust invasive 3-dimensional and clonogenic culture capability and form solid tumors when xenografted into immunodeficient mice. High-density single nucleotide polymorphism array and whole exome sequencing analyses indicate that, unlike NF1-associated MPNSTs, 2XSB cells have intact, functional NF1 alleles with no evidence of mutations in genes encoding components of Polycomb Repressor Complex 2. However, mutations in other genes implicated in MPNST pathogenesis were identified in 2XSB cells including homozygous deletion of CDKN2A and mutations in TP53 and PTEN. We also identified mutations in genes not previously associated with MPNSTs but associated with the pathogenesis of other human cancers. These include DNMT1, NUMA1, NTRK1, PDE11A, CSMD3, LRP5 and ACTL9 . This sporadic MPNST-derived cell line provides a useful tool for investigating the biology and potential treatment regimens for sporadic MPNSTs.

The proximal long arm of chromosome 15 has segmental duplications located at breakpoints BP1–BP5 that mediate the generation of NAHR-related microdeletions and microduplications. The classical Prader-Willi/Angelman syndrome deletion is flanked by either of the proximal BP1 or BP2 breakpoints and the distal BP3 breakpoint. The larger Type I deletions are flanked by BP1 and BP3 in both Prader-Willi and Angelman syndrome subjects. Those with this deletion are reported to have a more severe phenotype than individuals with either Type II deletions (BP2–BP3) or uniparental disomy 15. The BP1–BP2 region spans approximately 500 kb and contains four evolutionarily conserved genes that are not imprinted. Reports of mutations or disturbed expression of these genes appear to impact behavioral and neurological function in affected individuals. Recently, reports of deletions and duplications flanked by BP1 and BP2 suggest an association with speech and motor delays, behavioral problems, seizures, and autism. We present a large cohort of subjects with copy number alteration of BP1 to BP2 with common phenotypic features. These include autism, developmental delay, motor and language delays, and behavioral problems, which were present in both cytogenetic groups. Parental studies demonstrated phenotypically normal carriers in several instances, and mildly affected carriers in others, complicating phenotypic association and/or causality. Possible explanations for these results include reduced penetrance, altered gene dosage on a particular genetic background, or a susceptibility region as reported for other areas of the genome implicated in autism and behavior disturbances.

Targeted mutation assessment of 81 genes in 1021 adults with de novo acute myeloid leukemia (AML) identified recurrent mutations in the neurofibromin 1 (NF1) gene in 52 (5.1%) patients, including 36 (5.2%) younger and 16 (4.8%) older patients, which suggests NF1 belongs to the 20 most frequently mutated genes in adult AML. NF1 mutations were found throughout the gene, and comprised missense, frameshift, and nonsense mutations. One mutation hotspot, at amino acid threonine 676 (Thr676), was found in 27% of AML patients with NF1 mutations. NF1-mutated patients belonged more often to the adverse European LeukemiaNet (ELN) risk category than NF1 wild-type patients. Among patients aged <60 years, the presence of NF1 Thr676 mutations was associated with lower complete remission (CR) rates (P = 0.04) and shorter overall survival (OS; P = 0.01), as was the presence of any NF1 mutation in patients in the adverse ELN risk category (CR, P = 0.05; OS, P < 0.001). CR rates were also lower in NF1-mutated patients aged ≥60 years compared with NF1 wild-type patients (P = 0.001). In summary, our findings provide novel insights into the frequency of NF1 mutations in AML, and are suggestive of an adverse prognostic impact in patients treated with standard chemotherapy.

This study outlines the development of a microRNA signature in patients with cytogenetically normal acute myeloid leukemia (AML) with high-risk molecular features. This type of AML constitutes approximately 65% of cases of cytogenetically normal AML and one third of all AML cases involving patients under the age of 60 years. The microRNA signature correlated not only with the clinical outcome but also with the expression of genes encoding proteins of the innate immune system. This study outlines the development of a microRNA signature in patients with cytogenetically normal AML with high-risk molecular features. The microRNA signature correlated not only with the clinical outcome but also with the expression of genes encoding proteins of the innate immune system. In almost half of patients with acute myeloid leukemia (AML), no cytogenetic abnormality is detectable in the leukemic cells. Such patients are in an intermediate-risk prognostic category, 1 but among them are subgroups of patients who have molecular markers associated with either a favorable prognosis or an unfavorable prognosis. 2 Gene-expression profiling can also identify subgroups of patients who have cytogenetically normal AML with different outcomes. 3 – 5 Patients with internal tandem duplication in the fms-related tyrosine kinase 3 gene ( FLT3 -ITD) and those without FLT3 -ITD but with the wild-type nucleophosmin ( NPM1 ) gene are in a high-risk group, whereas . . .