Publications by authors named "Marian H Harris"

48 Publications

Matched Targeted Therapy for Pediatric Patients with Relapsed, Refractory, or High-Risk Leukemias: A Report from the LEAP Consortium.

Cancer Discov 2021 Jun 9;11(6):1424-1439. Epub 2021 Feb 9.

Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Despite a remarkable increase in the genomic profiling of cancer, integration of genomic discoveries into clinical care has lagged behind. We report the feasibility of rapid identification of targetable mutations in 153 pediatric patients with relapsed/refractory or high-risk leukemias enrolled on a prospective clinical trial conducted by the LEAP Consortium. Eighteen percent of patients had a high confidence Tier 1 or 2 recommendation. We describe clinical responses in the 14% of patients with relapsed/refractory leukemia who received the matched targeted therapy. Further, in order to inform future targeted therapy for patients, we validated variants of uncertain significance, performed drug-sensitivity testing in patient leukemia samples, and identified new combinations of targeted therapies in cell lines and patient-derived xenograft models. These data and our collaborative approach should inform the design of future precision medicine trials. SIGNIFICANCE: Patients with relapsed/refractory leukemias face limited treatment options. Systematic integration of precision medicine efforts can inform therapy. We report the feasibility of identifying targetable mutations in children with leukemia and describe correlative biology studies validating therapeutic hypotheses and novel mutations...
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http://dx.doi.org/10.1158/2159-8290.CD-20-0564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8178162PMC
June 2021

Genetic ancestry and skeletal toxicities among childhood acute lymphoblastic leukemia patients in the DFCI 05-001 cohort.

Blood Adv 2021 01;5(2):451-458

Jacob School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY.

Hispanic children have a higher incidence of acute lymphoblastic leukemia (ALL) and inferior treatment outcomes relative to non-Hispanic White children. We previously reported that Hispanic children with ALL had lower risk of fracture and osteonecrosis. To unravel the genetic root of such ethnic differences, we genotyped 449 patients from the DFCI 05-001 cohort and analyzed their ancestry. Patients with discordant clinical and genetic ancestral groups were reclassified, and those with unknown ancestry were reassigned on the basis of genetic estimates. Both clinical and genetic ancestries were analyzed in relation to risk of bone toxicities and survival outcomes. Consistent with clinically reported race/ethnicity, genetically defined Hispanic and Black patients had significantly lower risk of fracture (Hispanic: subdistribution hazard ratio [SHR], 0.42; 95% confidence interval [CI], 0.22-0.81; P = .01; Black: SHR, 0.28; 95% CI, 0.10-0.75; P = .01), and osteonecrosis (Hispanic: SHR, 0.12; 95% CI, 0.02-0.93; P = .04; Black: SHR, 0.24; 95% CI, 0.08-0.78; P = .02). The lower risk was driven by African but not Native American or Asian ancestry. In addition, patients with a higher percentage of Native American ancestry had significantly poorer overall survival and event-free survival. Our study revealed that the lower risk of bone toxicities among Black and Hispanic children treated for ALL was attributed, in part, to the percentage of African ancestry in their genetic admixture. The findings provide suggestive evidence for the protective effects of genetic factors associated with African decent against bone damage caused by ALL treatment and clues for future studies to identify underlying biological mechanisms.
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http://dx.doi.org/10.1182/bloodadvances.2020003060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7839368PMC
January 2021

Single-cell RNA-seq reveals developmental plasticity with coexisting oncogenic states and immune evasion programs in ETP-ALL.

Blood 2021 May;137(18):2463-2480

Broad Institute of MIT and Harvard, Cambridge, MA.

Lineage plasticity and stemness have been invoked as causes of therapy resistance in cancer, because these flexible states allow cancer cells to dedifferentiate and alter their dependencies. We investigated such resistance mechanisms in relapsed/refractory early T-cell progenitor acute lymphoblastic leukemia (ETP-ALL) carrying activating NOTCH1 mutations via full-length single-cell RNA sequencing (scRNA-seq) of malignant and microenvironmental cells. We identified 2 highly distinct stem-like states that critically differed with regard to cell cycle and oncogenic signaling. Fast-cycling stem-like leukemia cells demonstrated Notch activation and were effectively eliminated in patients by Notch inhibition, whereas slow-cycling stem-like cells were Notch independent and rather relied on PI3K signaling, likely explaining the poor efficacy of Notch inhibition in this disease. Remarkably, we found that both stem-like states could differentiate into a more mature leukemia state with prominent immunomodulatory functions, including high expression of the LGALS9 checkpoint molecule. These cells promoted an immunosuppressive leukemia ecosystem with clonal accumulation of dysfunctional CD8+ T cells that expressed HAVCR2, the cognate receptor for LGALS9. Our study identified complex interactions between signaling programs, cellular plasticity, and immune programs that characterize ETP-ALL, illustrating the multidimensionality of tumor heterogeneity. In this scenario, combination therapies targeting diverse oncogenic states and the immune ecosystem seem most promising to successfully eliminate tumor cells that escape treatment through coexisting transcriptional programs.
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http://dx.doi.org/10.1182/blood.2019004547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109012PMC
May 2021

Identification of prognostic factors in childhood T-cell acute lymphoblastic leukemia: Results from DFCI ALL Consortium Protocols 05-001 and 11-001.

Pediatr Blood Cancer 2021 01 7;68(1):e28719. Epub 2020 Oct 7.

Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.

Background/objectives: While outcomes for pediatric T-cell acute lymphoblastic leukemia (T-ALL) are favorable, there are few widely accepted prognostic factors, limiting the ability to risk stratify therapy.

Design/methods: Dana-Farber Cancer Institute (DFCI) Protocols 05-001 and 11-001 enrolled pediatric patients with newly diagnosed B- or T-ALL from 2005 to 2011 and from 2012 to 2015, respectively. Protocol therapy was nearly identical for patients with T-ALL (N = 123), who were all initially assigned to the high-risk arm. End-induction minimal residual disease (MRD) was assessed by reverse transcription polymerase chain reaction (RT-PCR) or next-generation sequencing (NGS), but was not used to modify postinduction therapy. Early T-cell precursor (ETP) status was determined by flow cytometry. Cases with sufficient diagnostic DNA were retrospectively evaluated by targeted NGS of known genetic drivers of T-ALL, including Notch, PI3K, and Ras pathway genes.

Results: The 5-year event-free survival (EFS) and overall survival (OS) for patients with T-ALL was 81% (95% CI, 73-87%) and 90% (95% CI, 83-94%), respectively. ETP phenotype was associated with failure to achieve complete remission, but not with inferior OS. Low end-induction MRD (<10 ) was associated with superior disease-free survival (DFS). Pathogenic mutations of the PI3K pathway were mutually exclusive of ETP phenotype and were associated with inferior 5-year DFS and OS.

Conclusions: Together, our findings demonstrate that ETP phenotype, end-induction MRD, and PI3K pathway mutation status are prognostically relevant in pediatric T-ALL and should be considered for risk classification in future trials. DFCI Protocols 05-001 and 11-001 are registered at www.clinicaltrials.gov as NCT00165087 and NCT01574274, respectively.
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http://dx.doi.org/10.1002/pbc.28719DOI Listing
January 2021

Making the most of small samples: Optimization of tissue allocation of pediatric solid tumors for clinical and research use.

Pediatr Blood Cancer 2020 09 15;67(9):e28326. Epub 2020 Jul 15.

Department of Pathology, Boston Children's Hospital, Boston, Massachusetts.

Introduction: Tissue from pediatric solid tumors is in high demand for use in high-impact research studies, making the allocation of tissue from an anatomic pathology laboratory challenging. We designed, implemented, and assessed an interdepartmental process to optimize tissue allocation of pediatric solid tumors for both clinical care and research.

Methods: Oncologists, pathologists, surgeons, interventional radiologists, pathology technical staff, and clinical research coordinators participated in the workflow design. Procedures were created to address patient identification and consent, prioritization of protocols, electronic communication of requests, tissue preparation, and distribution. Pathologists were surveyed about the value of the new workflow.

Results: Over a 5-year period, 644 pediatric solid tumor patients consented to one or more studies requesting archival or fresh tissue. Patients had a variety of tumor types, with many rare and singular diagnoses. Sixty-seven percent of 1768 research requests were fulfilled. Requests for archival tissue were fulfilled at a significantly higher rate than those for fresh tissue (P > .001), and requests from resection specimens were fulfilled at a significantly higher rate than those from biopsies (P > .0001). In an anonymous survey, seven of seven pathologists reported that the process had improved since the introduction of the electronic communication model.

Conclusions: A collaborative and informed model for tissue allocation is successful in distributing archival and fresh tissue for clinical research studies. Our workflows and policies have gained pathologists' approval and streamlined our processes. As clinical and research programs evolve, a thoughtful tissue allocation process will facilitate ongoing research.
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http://dx.doi.org/10.1002/pbc.28326DOI Listing
September 2020

Recurrent RET gene fusions in paediatric spindle mesenchymal neoplasms.

Histopathology 2020 Jun 15;76(7):1032-1041. Epub 2020 May 15.

Department of Pathology, Boston Children's Hospital, Boston, MA, USA.

Aims: The classification of paediatric spindle mesenchymal tumours is evolving, and the spectrum of so-called 'infantile fibrosarcoma' has expanded to include tumours with NTRK, BRAF and MET gene fusions. RET-rearranged paediatric spindle cell neoplasms are an emerging group; there is sparse literature on their clinical, pathological and genetic features, and their nosological place in the canon of soft tissue tumours is uncertain. In this study, we report five RET-rearranged paediatric spindle cell tumours with fusion partners MYH10, KIAA1217 and CLIP2.

Methods And Results: The tumours occurred in the pelvic region, paraspinal region, kidney and subcutaneous tissue of hand and abdomen. The patients' ages ranged from 6 months to 13 years (median 1 year). The tumours were composed of monomorphic spindle cells arranged in a fascicular pattern. Lesional cells had minimally atypical ovoid or tapered nuclei and pale cytoplasm with indistinct borders. Necrosis was not identified. Mitoses numbered three to 12 per 10 high-power field. Cases showed inconsistent and variable expression of S100, CD34 and SMA. Clinical behaviour ranged from small lesions potentially cured by simple resection to large lesions exhibiting metastasis, but responsive to kinase inhibitor therapy.

Conclusions: Our findings help to define RET-rearranged spindle cell tumours. Although it is likely that these tumours comprise part of the morphological and clinical spectrum of infantile fibrosarcoma (IFS), identification of RET gene alteration is important for its unique therapeutic implications.
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http://dx.doi.org/10.1111/his.14082DOI Listing
June 2020

Recurrent and novel USP6 fusions in cranial fasciitis identified by targeted RNA sequencing.

Mod Pathol 2020 05 11;33(5):775-780. Epub 2019 Dec 11.

Department of Pathology, Boston Children's Hospital, Boston, MA, USA.

Cranial fasciitis is a benign myofibroproliferative lesion of the scalp and underlying bones typically occurring in the pediatric population. Histologically, it is characterized by loose fascicles of stellate cells in a fibromyxoid background, findings similar to those described in the closely related variant nodular fasciitis. Previously characterized as a reactive process, the identification of USP6 translocations in over 90% of nodular fasciitis cases prompted their reclassification as a clonal neoplastic process. Unlike nodular fasciitis, the molecular underpinnings of cranial fasciitis are less clear. While a subset of cranial fasciitis has been associated with Wnt/β-catenin pathway dysregulation, recent case reports suggest that this entity may also harbor USP6 fusions, a finding we sought to further investigate. We identified fifteen archival cases of cranial fasciitis, five females and ten males ranging in age from 3 months to 9 years (median 11 months), composed of formalin-fixed paraffin-embedded and fresh frozen tissues (11 and 4 cases respectively). Samples were evaluated on an RNA-based targeted sequencing panel targeting genes recurrently rearranged in neoplasia, including USP6. Five of fifteen cases (33%) were positive for USP6 rearrangements predicted to result in the fusion of the entire USP6 coding region to the promoter of the 5' partner, (three of which were novel):  two SERPINH1-USP6 (novel) and one each of COL3A1-USP6 (novel), SPARC-USP6, and MYH9-USP6. These results demonstrate the recurrent nature of USP6 rearrangements in cranial fasciitis, and highlight the success of targeted RNA sequencing in identifying known and novel fusion partners. The identification of USP6 promoter-swapping rearrangements is helpful in understanding the underlying biology of cranial fasciitis, and reinforces its biologic relationship to nodular fasciitis. Targeted RNA sequencing is a helpful tool in diagnosing this pseudosarcomatous lesion.
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http://dx.doi.org/10.1038/s41379-019-0422-6DOI Listing
May 2020

Fanconi-BRCA pathway mutations in childhood T-cell acute lymphoblastic leukemia.

PLoS One 2019 13;14(11):e0221288. Epub 2019 Nov 13.

Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts, United States of America.

BRCA2 (also known as FANCD1) is a core component of the Fanconi pathway and suppresses transformation of immature T-cells in mice. However, the contribution of Fanconi-BRCA pathway deficiency to human T-cell acute lymphoblastic leukemia (T-ALL) remains undefined. We identified point mutations in 9 (23%) of 40 human T-ALL cases analyzed, with variant allele fractions consistent with heterozygous mutations early in tumor evolution. Two of these mutations were present in remission bone marrow specimens, suggesting germline alterations. BRCA2 was the most commonly mutated gene. The identified Fanconi-BRCA mutations encode hypomorphic or null alleles, as evidenced by their inability to fully rescue Fanconi-deficient cells from chromosome breakage, cytotoxicity and/or G2/M arrest upon treatment with DNA cross-linking agents. Disabling the tumor suppressor activity of the Fanconi-BRCA pathway is generally thought to require biallelic gene mutations. However, all mutations identified were monoallelic, and most cases appeared to retain expression of the wild-type allele. Using isogenic T-ALL cells, we found that BRCA2 haploinsufficiency induces selective hypersensitivity to ATR inhibition, in vitro and in vivo. These findings implicate Fanconi-BRCA pathway haploinsufficiency in the molecular pathogenesis of T-ALL, and provide a therapeutic rationale for inhibition of ATR or other druggable effectors of homologous recombination.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0221288PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6853288PMC
March 2020

A Distinctive Genomic and Immunohistochemical Profile for NOTCH3 and PDGFRB in Myofibroma With Diagnostic and Therapeutic Implications.

Int J Surg Pathol 2020 Apr 29;28(2):128-137. Epub 2019 Sep 29.

Boston Children's Hospital, Boston, MA, USA.

. Myofibromas are rare tumors of pericytic lineage, typically affecting children, and are sometimes aggressive. A subset of sporadic and familial myofibromas have activating variants in . The relationship of myofibroma and PDGFRB to the NOTCH pathway has not yet been described. . Ten myofibroma cases were sequenced with a targeted panel of 447 genes, including copy number variation and selected fusions. Immunohistochemical analysis of total NOTCH3 and activated NOTCH3 was assessed for all 10 myofibroma cases, and a series of histologic mimics (n = 20). . Alterations identified by next-generation sequencing included sequence variants in 8/10 cases (80%), a variant in 1/10 cases (10%), and a variant in 1/10 cases (10%). All 10 cases also showed a pattern of low-amplitude (1.5- to 2-fold) copy number alterations including gains in and . Ten of 10 myofibromas (100%) showed cytoplasmic staining for total NOTCH3 and 9 of 10 cases (90%) showed nuclear staining for activated NOTCH3. Within the control cohort of histologic mimics, 3 of 3 nodular fasciitis cases (100%) were positive for activated and total NOTCH3, and the remaining 17 cases were negative for pan NOTCH3, while 3 of 3 desmoid-type fibromatosis cases (100%) showed patchy weak nuclear staining for activated NOTCH3. . Our findings suggest a common pathway of PDGFRB/NOTCH3 activation in myofibromas, even in cases that lack sequence variants. These results support the pericytic lineage of myofibroma. Identification of the characteristic genomic alterations or immunohistochemical staining pattern may facilitate a difficult pathologic diagnosis, and support the use of targeted treatments.
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http://dx.doi.org/10.1177/1066896919876703DOI Listing
April 2020

Genetic Testing in the Diagnosis and Biology of Acute Leukemia.

Am J Clin Pathol 2019 08;152(3):322-346

Department of Pathology and Laboratory Medicine, Indiana University, Indianapolis.

Objectives: The 2017 Workshop of the Society for Hematopathology/European Association for Haematopathology examined the role of molecular genetics in the diagnosis and biology of acute leukemia.

Methods: Acute leukemias were reviewed in two sessions: "Genetic Testing in Diagnosis of Acute Leukemias" (53 cases) and "Genetics Revealing the Biology of Acute Leukemias" (41 cases).

Results: Cases included acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemia of ambiguous lineage. Many cases demonstrated genetic alterations of known diagnostic, prognostic, and/or therapeutic significance, while others exhibited alterations that illuminated disease biology. The workshop highlighted the complexity of acute leukemia diagnosis and follow-up, while illustrating advantages and pitfalls of molecular genetic testing.

Conclusions: Our understanding of the molecular genetics of acute leukemias continues to grow rapidly. Awareness of the potential complexity of genetic architecture and environment is critical and emphasizes the importance of integrating clinical information with morphologic, immunophenotypic, and molecular genetic evaluation.
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http://dx.doi.org/10.1093/ajcp/aqz093DOI Listing
August 2019

High NPM1 mutant allele burden at diagnosis correlates with minimal residual disease at first remission in de novo acute myeloid leukemia.

Am J Hematol 2019 08 17;94(8):921-928. Epub 2019 Jun 17.

Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts.

Acute myeloid leukemia (AML) with mutated NPM1 is a newly recognized separate entity in the revised 2016 WHO classification, and is associated with a favorable prognosis. While previous studies have evaluated NPM1 in a binary fashion, we recently demonstrated a significant independent negative prognostic effect of high NPM1 mutant allele burden (VAF) at diagnosis in a cohort of de novo AML patients. Although the importance of minimal residual disease (MRD) monitoring in NPM1-mutated AML has been well characterized, the potential relationship between diagnostic allele burden and MRD is unknown. We retrospectively evaluated for MRD at first remission (CR1). We used either next-generation sequencing (NGS) [n = 71], and/or immunohistochemistry (IHC) for mutant NPM1 (NPM1c) [n = 60], in a subset of patients from our recently examined cohort. We identified a statistically significant positive correlation between the VAF at diagnosis, and at CR1 (Spearman r = 0.4, P = .006), and enrichment for MRD in high diagnostic VAF patients (P = .05), as previously defined. IHC-positivity also correlated significantly with a higher median diagnostic NPM1 VAF (0.42 vs 0.39, P = .02), and with the VAF at CR1 (Spearman r = 0.7, P = .003). In multivariable analyses, both high diagnostic VAF (P = .003) and MRD (P = .02) were independent predictors of shorter event-free survival (EFS). Our findings suggest a relationship between the NPM1 mutant allele burden at diagnosis, and the presence of MRD at first remission. Our findings support IHC as a potentially useful adjunctive tool for disease monitoring.
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http://dx.doi.org/10.1002/ajh.25544DOI Listing
August 2019

Genomic and clinical characterization of B/T mixed phenotype acute leukemia reveals recurrent features and T-ALL like mutations.

Am J Hematol 2018 11 26;93(11):1358-1367. Epub 2018 Sep 26.

Department of Pathology, Boston Children's Hospital, Boston, Massachusetts.

The B/T subtype of mixed phenotype acute leukemia (B/T MPAL) is defined by co-expression of antigens of both B- and T-cell lineages on leukemic blasts. Although it has been suggested that multilineage antigen expression portends poor response to chemotherapy, the clinical characteristics and driver mutations that underlie the pathogenesis of this rare subtype of acute leukemia are scarcely known. We identified nine cases of B/T MPAL from multiple institutions and correlated clinical and immunophenotypic findings with next-generation sequencing data. We report that B/T MPAL commonly presents with lymphadenopathy in adolescence and young adulthood. While the tumors have diverse cytogenetic and genomic perturbations, recurrent acquired aberrations include mutations in the putative transcriptional regulator PHF6 and the JAK-STAT and Ras signaling pathways. Alterations were also identified in genes encoding hematopoietic transcription factors, cell cycle regulators/tumor suppressors, and chromatin modifying enzymes. The genomic landscape of B/T MPAL strongly resembles that of T-ALL subgroups associated with early developmental arrest, while genetic alterations that are common in B-ALL were rarely seen. Two-thirds of the patients responded to ALL-based chemotherapy with or without stem cell transplantation. Our observations lay the groundwork for further study of the unique biology and clinical trajectory of B/T MPAL.
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http://dx.doi.org/10.1002/ajh.25256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193761PMC
November 2018

Refining risk classification in childhood B acute lymphoblastic leukemia: results of DFCI ALL Consortium Protocol 05-001.

Blood Adv 2018 06;2(12):1449-1458

Department of Pediatric Oncology, Dana-Farber Cancer Institute.

Dana-Farber Cancer Institute (DFCI) ALL Consortium Protocol 05-001 tested a new risk stratification system in children and adolescents with newly diagnosed acute lymphoblastic leukemia (ALL). At study entry, B-ALL patients were classified as standard risk (SR) or high risk (HR) based on age, white blood cell (WBC) count, and central nervous system status. After achieving complete remission (CR), patients with high end-induction minimal residual disease (MRD) (≥10 by polymerase chain reaction analysis of patient-specific antigen receptor rearrangements) and/or adverse cytogenetics ( rearrangement or hypodiploidy) were reclassified as very high risk (VHR) and received intensified therapy. deletion status was retrospectively evaluated by multiplex ligation-dependent probe amplification. Between 2005 and 2011, 678 Philadelphia chromosome-negative B-ALL patients aged 1 to 18 years enrolled; 651 achieved CR and 648 received a final risk group. Among all 678 patients, 5-year event-free survival (EFS) was 87% (95% confidence interval [CI], 84-89) and overall survival 93% (95% CI, 90-94). Five-year disease-free survival of SR patients (N = 407) was 94% (95% CI, 91-96), HR (N = 176) was 84% (95% CI, 77-88), and VHR (N = 65) was 79% (95% CI, 67-87). deletion was present in 62 of 385 (16%) assessed patients and was associated with inferior 5-year EFS (63%; 95% CI, 49%-74% vs 88%; 95% CI, 84%-91%; < .001), and higher 5-year cumulative incidence of relapse, including among those with low MRD (24% vs 8%, = .001). In multivariable analysis, age ≥15 years, WBC ≥50 × 10/L, deletion, and MRD ≥10 was each associated with inferior outcome. In conclusion, risk-stratified therapy on DFCI 05-001 resulted in favorable outcomes for B-ALL patients, including those with VHR features. deletion was an independent predictor of inferior outcome. This trial was registered at www.clinicaltrials.gov as #NCT00400946.
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http://dx.doi.org/10.1182/bloodadvances.2018016584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6020806PMC
June 2018

Outcome of children and adolescents with Down syndrome treated on Dana-Farber Cancer Institute Acute Lymphoblastic Leukemia Consortium protocols 00-001 and 05-001.

Pediatr Blood Cancer 2018 10 7;65(10):e27256. Epub 2018 Jun 7.

Department of Pediatric Oncology, Dana-Farber Cancer Institute and Division of Pediatric Hematology-Oncology, Boston Children's Hospital, Boston, MA, USA.

Background: Children and adolescents with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) are reported to have increased relapse rates and therapy-related mortality (TRM). Treatment regimens for DS-ALL patients often include therapy modifications. Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols have used same risk-stratified treatment for patients with and without DS.

Procedures: We compared clinical and outcome data of DS (n = 38) and non-DS (n = 1,248) patients enrolled on two consecutive DFCI ALL trials 00-001 (2000-2004) and 05-001 (2005-2011) with similar risk adapted therapy regardless of DS status.

Results: There was no difference in demographic or presenting clinical features between two groups except absence of T-cell phenotype and lower frequency of hyperdiploidy in DS-ALL group. All DS-ALL patients achieved complete remission; four relapsed and one subsequently died. There was no TRM in DS-ALL patients. DS-ALL patients had significantly higher rates of mucositis (52% vs. 12%, p < 0.001), non-CNS thrombosis (18% vs. 8%; p = 0.036), and seizure (16% vs. 5%, p = 0.010). Compared to non-DS-ALL patients, DS-ALL patients had a higher incidence of infections during all therapy phases. The 5-year event-free and overall survival rates of DS-ALL patients were similar to non-DS-ALL patients (91% [95% confidence interval (CI), 81-100] vs. 84% [95% CI, 82-86]; 97% [95% CI, 92-100] vs. 91% [95% CI, 90-93]).

Conclusion: The low rates of relapse and TRM indicate that uniform risk-stratified therapy for DS-ALL and non-DS-ALL patients on DFCI ALL Consortium protocols was safe and effective, although the increased rate of toxicity in the DS-ALL patients highlights the importance of supportive care during therapy.
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http://dx.doi.org/10.1002/pbc.27256DOI Listing
October 2018

Hedgehog pathway mutations drive oncogenic transformation in high-risk T-cell acute lymphoblastic leukemia.

Leukemia 2018 10 20;32(10):2126-2137. Epub 2018 Mar 20.

Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, 02115, USA.

The role of Hedgehog signaling in normal and malignant T-cell development is controversial. Recently, Hedgehog pathway mutations have been described in T-ALL, but whether mutational activation of Hedgehog signaling drives T-cell transformation is unknown, hindering the rationale for therapeutic intervention. Here, we show that Hedgehog pathway mutations predict chemotherapy resistance in human T-ALL, and drive oncogenic transformation in a zebrafish model of the disease. We found Hedgehog pathway mutations in 16% of 109 childhood T-ALL cases, most commonly affecting its negative regulator PTCH1. Hedgehog mutations were associated with resistance to induction chemotherapy (P = 0.009). Transduction of wild-type PTCH1 into PTCH1-mutant T-ALL cells induced apoptosis (P = 0.005), a phenotype that was reversed by downstream Hedgehog pathway activation (P = 0.007). Transduction of most mutant PTCH1, SUFU, and GLI alleles into mammalian cells induced aberrant regulation of Hedgehog signaling, indicating that these mutations are pathogenic. Using a CRISPR/Cas9 system for lineage-restricted gene disruption in transgenic zebrafish, we found that ptch1 mutations accelerated the onset of notch1-induced T-ALL (P = 0.0001), and pharmacologic Hedgehog pathway inhibition had therapeutic activity. Thus, Hedgehog-activating mutations are driver oncogenic alterations in high-risk T-ALL, providing a molecular rationale for targeted therapy in this disease.
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http://dx.doi.org/10.1038/s41375-018-0097-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6148437PMC
October 2018

Phase I trial of the mTOR inhibitor everolimus in combination with multi-agent chemotherapy in relapsed childhood acute lymphoblastic leukemia.

Pediatr Blood Cancer 2018 07 30;65(7):e27062. Epub 2018 Mar 30.

Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, Massachusetts.

Background: We sought to determine the feasibility of co-administering everolimus with a four-drug reinduction in children and adolescents with acute lymphoblastic leukemia (ALL) experiencing a first marrow relapse.

Procedure: This phase I study tested everolimus with vincristine, prednisone, pegaspargase and doxorubicin in patients with marrow relapse occurring >18 months after first complete remission (CR). The primary aim was to identify the maximum tolerated dose of everolimus. Three dose levels (DLs) were tested during dose escalation (2, 3, and 5 mg/m /day). Additional patients were enrolled at the 3- and 5 mg/m /day DLs to further evaluate toxicity (dose expansion).

Results: Thirteen patients enrolled during dose escalation and nine during dose expansion. During dose escalation, one dose-limiting toxicity occurred (grade 4 hyperbilirubinemia) in six evaluable patients at DL3 (5 mg/m /day). The most common grade ≥3 adverse events were febrile neutropenia, infections, transaminitis, hyperbilirubinemia, and hypophosphatemia. Two of the 12 patients treated at DL3 developed Rothia mucilaginosa meningitis. Nineteen patients (86%) achieved a second CR (CR2). Of those, 13 (68%) had a low end-reinduction minimal residual disease (MRD) level (≤10 by polymerase chain reaction-based assay). The CR2 rate for patients with B-cell ALL treated at DL3 (n = 12) was 92%; 82% of these patients had low MRD.

Conclusions: Everolimus combined with four-drug reinduction chemotherapy was generally well tolerated and associated with favorable rates of CR2 and low end-reinduction MRD. The recommended phase 2 dose of everolimus given in combination with a four-drug reinduction is 5 mg/m /day. This promising combination should be further evaluated in a larger patient cohort.
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http://dx.doi.org/10.1002/pbc.27062DOI Listing
July 2018

Prognostic impact of kinase-activating fusions and IKZF1 deletions in pediatric high-risk B-lineage acute lymphoblastic leukemia.

Blood Adv 2018 03;2(5):529-533

Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, MA.

Recurrent chromosomal rearrangements carry prognostic significance in pediatric B-lineage acute lymphoblastic leukemia (B-ALL). Recent genome-wide analyses identified a high-risk B-ALL subtype characterized by a diverse spectrum of genetic alterations activating kinases and cytokine receptor genes. This subtype is associated with a poor prognosis when treated with conventional chemotherapy but has demonstrated sensitivity to the relevant tyrosine kinase inhibitors. We sought to determine the frequency of kinase-activating fusions among National Cancer Institute (NCI) high-risk, Ph-negative, B-ALL patients enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 05-001 and to describe their associated clinical characteristics and outcomes. Among the 105 patients screened, 16 (15%) harbored an ABL-class fusion (: n = 1; : n = 1; : n = 1; : n = 1) or a fusion activating the JAK-STAT pathway (: n = 8; : n = 4). Sixty-nine percent of patients with an identified fusion had a concomitant deletion (n = 11). In univariate analysis, fusion-positivity and deletion were each associated with inferior event-free survival; deletion retained statistical significance in multivariable analysis (hazard ratio, 2.64; = .019). Our findings support therapy intensification for -altered patients, irrespective of the presence of a kinase-activating fusion.
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http://dx.doi.org/10.1182/bloodadvances.2017014704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5851421PMC
March 2018

Recurrent EML4-NTRK3 fusions in infantile fibrosarcoma and congenital mesoblastic nephroma suggest a revised testing strategy.

Mod Pathol 2018 03 3;31(3):463-473. Epub 2017 Nov 3.

Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.

Infantile fibrosarcoma and congenital mesoblastic nephroma are tumors of infancy traditionally associated with the ETV6-NTRK3 gene fusion. However, a number of case reports have identified variant fusions in these tumors. In order to assess the frequency of variant NTRK3 fusions, and in particular whether the recently identified EML4-NTRK3 fusion is recurrent, 63 archival cases of infantile fibrosarcoma, congenital mesoblastic nephroma, mammary analog secretory carcinoma and secretory breast carcinoma (tumor types that are known to carry recurrent ETV6-NTRK3 fusions) were tested with NTRK3 break-apart FISH, EML4-NTRK3 dual fusion FISH, and targeted RNA sequencing. The EML4-NTRK3 fusion was identified in two cases of infantile fibrosarcoma (one of which was previously described), and in one case of congenital mesoblastic nephroma, demonstrating that the EML4-NTRK3 fusion is a recurrent genetic event in these related tumors. The growing spectrum of gene fusions associated with infantile fibrosarcoma and congenital mesoblastic nephroma along with the recent availability of targeted therapies directed toward inhibition of NTRK signaling argue for alternate testing strategies beyond ETV6 break-apart FISH. The use of either NTRK3 FISH or next-generation sequencing will expand the number of cases in which an oncogenic fusion is identified and facilitate optimal diagnosis and treatment for patients.
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http://dx.doi.org/10.1038/modpathol.2017.127DOI Listing
March 2018

Clinical, Pathologic, and Genetic Features of Wilms Tumors With WTX Gene Mutation.

Pediatr Dev Pathol 2017 Mar-Apr;20(2):105-111. Epub 2017 Jan 26.

1 Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA.

Clinical and pathologic features of patients with WTX-mutated Wilms tumor (WT) have not been studied in detail. We characterize the clinical and pathologic findings in WT with WTX abnormalities and provide comparison with WT without WTX mutation. Clinical, gross, and microscopic features in 35 patients with WT were examined. Karyotype was examined in a subset of cases. All cases had been previously analyzed for WTX, WT1, and CTNNB1 aberrations via array comparative genomic hybridization; OncoMap 4 high throughput genotyping was performed on 18 cases. Eleven tumors had WTX abnormality. No significant differences were identified between patients with mutated versus nonmutated WTX with respect to gender (45% versus 33% male), age (mean 3.9 versus 4.1 years), tumor size (mean 12.7 cm versus 12.8 cm), anaplasia (9% versus 12%), rhabdomyoblastic differentiation (18% versus 8%), cartilage differentiation (9% versus 4%), mucinous epithelial differentiation (9% versus 4%), nephrogenic rests (28% versus 21%), or relapse rate (11% versus 25%). Mutations in KRAS, MYC, and PIK3R1 were restricted to WTX-mutated WT, mutations in AKT, CKDN2A, EFGR, HRAS, MET, and RET were restricted to WT without WTX mutation, and mutations in BRAF, CTTNB1, NRAS, PDGFRA, and STK11 were seen in both groups. Our study revealed no clinical or pathologic distinctions between WT with and without WTX abnormality. This similarity lends support to the concept of a common tumorigenic pathway between WT with aberrant WTX and those without.
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http://dx.doi.org/10.1177/1093526616683881DOI Listing
April 2019

Clinical targeted exome-based sequencing in combination with genome-wide copy number profiling: precision medicine analysis of 203 pediatric brain tumors.

Neuro Oncol 2017 Jul;19(7):986-996

Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Department of Pathology, Department of Radiology, Department of Neurosurgery, Boston Children's Hospital, Boston, Massachusetts; Department of Medical Oncology, Oncologic Pathology, Department of Pediatric Oncology, Department of Cancer Biology, Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Boston, Massachusetts; Department of Pathology, Department of Neurosurgery, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts; Pratiti Bandopadhayay, Broad Institute of MIT and Harvard, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.

Background: Clinical genomics platforms are needed to identify targetable alterations, but implementation of these technologies and best practices in routine clinical pediatric oncology practice are not yet well established.

Methods: Profile is an institution-wide prospective clinical research initiative that uses targeted sequencing to identify targetable alterations in tumors. OncoPanel, a multiplexed targeted exome-sequencing platform that includes 300 cancer-causing genes, was used to assess single nucleotide variants and rearrangements/indels. Alterations were annotated (Tiers 1-4) based on clinical significance, with Tier 1 alterations having well-established clinical utility. OncoCopy, a clinical genome-wide array comparative genomic hybridization (aCGH) assay, was also performed to evaluate copy number alterations and better define rearrangement breakpoints.

Results: Cancer genomes of 203 pediatric brain tumors were profiled across histological subtypes, including 117 samples analyzed by OncoPanel, 146 by OncoCopy, and 60 tumors subjected to both methodologies. OncoPanel revealed clinically relevant alterations in 56% of patients (44 cancer mutations and 20 rearrangements), including BRAF alterations that directed the use of targeted inhibitors. Rearrangements in MYB-QKI, MYBL1, BRAF, and FGFR1 were also detected. Furthermore, while copy number profiles differed across histologies, the combined use of OncoPanel and OncoCopy identified subgroup-specific alterations in 89% (17/19) of medulloblastomas.

Conclusion: The combination of OncoPanel and OncoCopy multiplex genomic assays can identify critical diagnostic, prognostic, and treatment-relevant alterations and represents an effective precision medicine approach for clinical evaluation of pediatric brain tumors.
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http://dx.doi.org/10.1093/neuonc/now294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5570190PMC
July 2017

Pediatric-type nodal follicular lymphoma: a biologically distinct lymphoma with frequent MAPK pathway mutations.

Blood 2016 08 20;128(8):1093-100. Epub 2016 Jun 20.

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA; Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA;

Pediatric-type nodal follicular lymphoma (PTNFL) is a variant of follicular lymphoma (FL) characterized by limited-stage presentation and invariably benign behavior despite often high-grade histological appearance. It is important to distinguish PTNFL from typical FL in order to avoid unnecessary treatment; however, this distinction relies solely on clinical and pathological criteria, which may be variably applied. To define the genetic landscape of PTNFL, we performed copy number analysis and exome and/or targeted sequencing of 26 PTNFLs (16 pediatric and 10 adult). The most commonly mutated gene in PTNFL was MAP2K1, encoding MEK1, with a mutation frequency of 43%. All MAP2K1 mutations were activating missense mutations localized to exons 2 and 3, which encode negative regulatory and catalytic domains, respectively. Missense mutations in MAPK1 (2/22) and RRAS (1/22) were identified in cases that lacked MAP2K1 mutations. The second most commonly mutated gene in PTNFL was TNFRSF14, with a mutation frequency of 29%, similar to that seen in limited-stage typical FL (P = .35). PTNFL was otherwise genomically bland and specifically lacked recurrent mutations in epigenetic modifiers (eg, CREBBP, KMT2D). Copy number aberrations affected a mean of only 0.5% of PTNFL genomes, compared with 10% of limited-stage typical FL genomes (P < .02). Importantly, the mutational profiles of PTNFLs in children and adults were highly similar. Together, these findings define PTNFL as a biologically and clinically distinct indolent lymphoma of children and adults characterized by a high prevalence of MAPK pathway mutations and a near absence of mutations in epigenetic modifiers.
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http://dx.doi.org/10.1182/blood-2015-12-682591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5000844PMC
August 2016

Characterization of a novel fusion gene EML4-NTRK3 in a case of recurrent congenital fibrosarcoma.

Cold Spring Harb Mol Case Stud 2015 Oct;1(1):a000471

Columbia University Medical Center, Department of Pediatric Oncology/Hematology/Stem Cell Transplantation, Department of Pediatrics, New York, New York 10032, USA;

We describe the clinical course of a recurrent case of congenital fibrosarcoma diagnosed in a 9-mo-old boy with a history of hemimelia. Following complete surgical resection of the primary tumor, the patient subsequently presented with bulky bilateral pulmonary metastases 6 mo following surgery. Molecular characterization of the tumor revealed the absence of the prototypical ETV6-NTRK3 translocation. However, tumor characterization incorporating cytogenetic, array comparative genomic hybridization, and RNA sequencing analyses, revealed a somatic t(2;15)(2p21;15q25) translocation resulting in the novel fusion of EML4 with NTRK3. Cloning and expression of EML4-NTRK3 in murine fibroblast NIH 3T3 cells revealed a potent tumorigenic phenotype as assessed in vitro and in vivo. These results demonstrate that multiple fusion partners targeting NTRK3 can contribute to the development of congenital fibrosarcoma.
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http://dx.doi.org/10.1101/mcs.a000471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4850889PMC
October 2015

The Public Repository of Xenografts Enables Discovery and Randomized Phase II-like Trials in Mice.

Cancer Cell 2016 04;29(4):574-586

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, 450 Brookline Avenue, Dana 510B, MA 02215, USA.

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease.
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http://dx.doi.org/10.1016/j.ccell.2016.03.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5177991PMC
April 2016

Multicenter Feasibility Study of Tumor Molecular Profiling to Inform Therapeutic Decisions in Advanced Pediatric Solid Tumors: The Individualized Cancer Therapy (iCat) Study.

JAMA Oncol 2016 May;2(5):608-615

Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts6Harvard Medical School, Boston, Massachusetts.

Importance: Pediatric cancers represent a unique case with respect to cancer genomics and precision medicine, as the mutation frequency is low, and targeted therapies are less available. Consequently, it is unknown whether clinical sequencing can be of benefit.

Objective: To assess the feasibility of identifying actionable alterations and making individualized cancer therapy (iCat) recommendations in pediatric patients with extracranial solid tumors.

Design, Setting, And Participants: Clinical sequencing study at 4 academic medical centers enrolling patients between September 5, 2012, and November 19, 2013, with 1 year of clinical follow-up. Participants were 30 years or younger with high-risk, recurrent, or refractory extracranial solid tumors. The data analysis was performed October 28, 2014.

Interventions: Tumor profiling performed on archived clinically acquired specimens consisted of mutation detection by a Sequenom assay or targeted next-generation sequencing and copy number assessment by array comparative genomic hybridization. Results were reviewed by a multidisciplinary expert panel, and iCat recommendations were made if an actionable alteration was present, and an appropriate drug was available.

Main Outcomes And Measures: Feasibility was assessed using a 2-stage design based on the proportion of patients with recommendations.

Results: Of 100 participants (60 male; median [range] age, 13.4 [0.8-29.8] years), profiling was technically successful in 89 (89% [95% CI, 83%-95%]). Median (range) follow-up was 6.8 (2.0-23.6) months. Overall, 31 (31% [95% CI, 23%-41%]) patients received an iCat recommendation and 3 received matched therapy. The most common actionable alterations leading to an iCat recommendation were cancer-associated signaling pathway gene mutations (n = 10) and copy number alterations in MYC/MYCN (n = 6) and cell cycle genes (n = 11). Additional alterations with implications for clinical care but not resulting in iCat recommendations were identified, including mutations indicating the possible presence of a cancer predisposition syndrome and translocations suggesting a change in diagnosis. In total, 43 (43% [95% CI, 33%-53%]) participants had results with potential clinical significance.

Conclusions And Relevance: A multi-institution clinical genomics study in pediatric oncology is feasible and a substantial proportion of relapsed or refractory pediatric solid tumors have actionable alterations.

Trial Registration: clinicaltrials.gov Identifier: NCT01853345.
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http://dx.doi.org/10.1001/jamaoncol.2015.5689DOI Listing
May 2016

Intravenous pegylated asparaginase versus intramuscular native Escherichia coli L-asparaginase in newly diagnosed childhood acute lymphoblastic leukaemia (DFCI 05-001): a randomised, open-label phase 3 trial.

Lancet Oncol 2015 Dec 6;16(16):1677-90. Epub 2015 Nov 6.

Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA. Electronic address:

Background: l-asparaginase is a universal component of treatment for childhood acute lymphoblastic leukaemia, and is usually administered intramuscularly. Pegylated Escherichia coli asparaginase (PEG-asparaginase) has a longer half-life and is potentially less immunogenic than the native Escherichia coli (E coli) preparation, and can be more feasibly administered intravenously. The aim of the Dana-Farber Cancer Institute Acute Lymphoblastic Leukaemia Consortium Protocol 05-001 (DFCI 05-001) was to compare the relative toxicity and efficacy of intravenous PEG-asparaginase and intramuscular native E colil-asparaginase in children with newly diagnosed acute lymphoblastic leukaemia.

Methods: DFCI 05-001 enrolled patients aged 1-18 years with newly diagnosed acute lymphoblastic leukaemia from 11 consortium sites in the USA and Canada. Patients were assigned to an initial risk group on the basis of their baseline characteristics and then underwent 32 days of induction therapy. Those who achieved complete remission after induction therapy were assigned to a final risk group and were eligible to participate in a randomised comparison of intravenous PEG-asparaginase (15 doses of 2500 IU/m(2) every 2 weeks) or intramuscular native E colil-asparaginase (30 doses of 25 000 IU/m(2) weekly), beginning at week 7 after study entry. Randomisation (1:1) was unmasked, and was done by a statistician-generated allocation sequence using a permuted blocks algorithm (block size of 4), stratified by final risk group. The primary endpoint of the randomised comparison was the overall frequency of asparaginase-related toxicities (defined as allergy, pancreatitis, and thrombotic or bleeding complications). Predefined secondary endpoints were disease-free survival, serum asparaginase activity, and quality of life during therapy as assessed by PedsQL surveys. All analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00400946.

Findings: Between April 22, 2005, and Feb 12, 2010, 551 eligible patients were enrolled. 526 patients achieved complete remission after induction, of whom 463 were randomly assigned to receive intramuscular native E colil-asparaginase (n=231) or intravenous PEG-asparaginase (n=232). The two treatment groups did not differ significantly in the overall frequency of asparaginase-related toxicities (65 [28%] of 232 patients in the intravenous PEG-asparaginase group vs 59 [26%] of 231 patients in the intramuscular native E colil-asparaginase group, p=0·60), or in the individual frequency of allergy (p=0·36), pancreatitis (p=0·55), or thrombotic or bleeding complications (p=0·26). Median follow-up was 6·0 years (IQR 5·0-7·1). 5-year disease-free survival was 90% (95% CI 86-94) for patients assigned to intravenous PEG-asparaginase and 89% (85-93) for those assigned to intramuscular native E colil-asparaginase (p=0·58). The median nadir serum asparaginase activity was significantly higher in patients who received intravenous PEG-asparaginase than in those who received intramuscular native E colil-asparaginase. Significantly more anxiety was reported by both patients and parent-proxy in the intramuscular native E colil-asparaginase group than in the intravenous PEG-asparaginase group. Scores for other domains were similar between the groups. The most common grade 3 or worse adverse events were bacterial or fungal infections (47 [20%] of 232 in the intravenous PEG-asparaginase group vs 51 [22%] of 231 patients in the intramuscular E colil-asparaginase group) and asparaginase-related allergic reactions (14 [6%] vs 6 [3%]).

Interpretation: Intravenous PEG-asparaginase was not more toxic than, was similarly efficacious to, and was associated with decreased anxiety compared with intramuscular native E colil-asparaginase, supporting its use as the front-line asparaginase preparation in children with newly diagnosed acute lymphoblastic leukaemia.

Funding: National Cancer Institute and Enzon Pharmaceuticals.
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http://dx.doi.org/10.1016/S1470-2045(15)00363-0DOI Listing
December 2015

Imaging findings in children with proliferative disorders following multivisceral transplantation.

Pediatr Radiol 2015 Jul 22;45(8):1138-45. Epub 2015 Mar 22.

Department of Radiology, Tufts Medical Center, Boston, MA, USA.

Background: Multivisceral transplantation represents an important treatment option for children with intestinal failure. The attendant immunosuppression can lead to a spectrum of cellular proliferations including benign and malignant smooth muscle tumors and lymphoproliferative disorders, many related to cellular dysregulation from Epstein-Barr virus infection.

Objective: The purpose of this study is to investigate the rates of post-transplantation proliferative disorders among children with multivisceral transplantation and to characterize the imaging and pathological features of these disorders.

Materials And Methods: We identified all consecutive children who underwent multivisceral transplant from August 2004 to October 2011 with at least 27 months of clinical and imaging follow-up. We reviewed medical records to determine the underlying causes of the multivisceral transplant, age at transplantation, onset of neoplasm development, and outcome. Two pediatric radiologists reviewed all imaging studies independently and diagnosis of disease was made by consensus interpretation. Pathological specimens were reviewed for histopathological findings of post-transplantation neoplasm in this pediatric patient population.

Results: The study population consisted of 14 consecutive pediatric patients (7 boys and 7 girls; mean age 26 months, range 4-113 months). Of these 14 children, 4 (29%) developed histologically confirmed post-transplant neoplasms at a mean time of 2.4 years after multivisceral transplantation. Types of neoplasms included post-transplant lymphoproliferative disorder (PTLD) in three (21%) and Epstein-Barr-virus-associated smooth muscle tumor in two (14%). (One child developed both neoplasms following transplantation). Both children with smooth muscle tumor associated with Epstein-Barr virus presented with characteristic hypointense solid masses with peripheral rim enhancement on cross-sectional imaging studies. The mortality rate of children who developed post-transplant neoplasms was higher than that of those who did not develop post-transplant neoplasm (50% vs. 10%, P = 0.17), suggesting a possible risk factor for death.

Conclusion: Post-transplant neoplasm in children with multivisceral transplantation occurs with high frequency, often presents as Epstein-Barr-virus-associated smooth muscle tumor showing characteristic peripheral rim enhancement on cross-sectional imaging studies.
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http://dx.doi.org/10.1007/s00247-015-3303-2DOI Listing
July 2015

Pediatric aplastic anemia and refractory cytopenia: A retrospective analysis assessing outcomes and histomorphologic predictors.

Am J Hematol 2015 Apr 2;90(4):320-6. Epub 2015 Mar 2.

Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.

Pediatric acquired aplastic anemia (AA) is a bone marrow disorder that is difficult to distinguish from inherited bone marrow failure syndromes and hypocellular refractory cytopenia of childhood (RCC). Historically, patients with hypocellular RCC have been given the diagnosis of AA. To assess the clinical and histologic distinction between RCC and AA, we performed a retrospective analysis of 149 patients previously diagnosed with AA between 1976 and 2010. We evaluated event free survival (EFS), overall survival (OS), response rates to immunosuppressive therapy, treatment-related toxicities and clonal evolution. The 5-year EFS and OS were 50.8% ± 5.5% and 73.1% ± 4.7%, respectively. Patients with very severe AA had worse OS compared to patients with severe and moderately severe AA. Seventy-two patients had diagnostic pathology specimens available for review. Three pediatric hematopathologists reviewed and reclassified these specimens as AA, RCC or Other based on 2008 WHO Criteria. The concordance between pathologists in the diagnosis of AA or RCC was modest. RCC was associated with a trend toward improved OS and EFS and was not prognostic of immunosuppression therapy treatment failure. There was a low rate of clonal evolution exclusively associated with moderately severe AA. Our findings indicate that a diagnosis of RCC is difficult to establish with certainty and does not predict outcomes, calling into question the reproducibility and clinical significance of the RCC classification and warranting further studies.
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http://dx.doi.org/10.1002/ajh.23937DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384448PMC
April 2015