Characteristics and outcome of patients with acute myeloid leukaemia and t(8;16)(p11;p13): results from an International Collaborative Study.

In acute myeloid leukaemia (AML) t(8;16)(p11;p13)/MYST3-CREBBP is a very rare abnormality. Previous small series suggested poor outcome. We report on 59 patients with t(8;16) within an international, collaborative study. Median age was 52 (range: 16-75) years. AML was de novo in 58%, therapy-related (t-AML) in 37% and secondary after myelodysplastic syndrome (s-AML) in 5%. Cytogenetics revealed a complex karyotype in 43%. Besides MYST3-CREBBP, whole-genome sequencing on a subset of 10 patients revealed recurrent mutations in ASXL1, BRD3, FLT3, MLH1, POLG, TP53, SAMD4B (n = 3, each), EYS, KRTAP9-1 SPTBN5 (n = 4, each), RUNX1 and TET2 (n = 2, each). Complete remission after intensive chemotherapy was achieved in 84%. Median follow-up was 5·48 years; five-year survival rate was 17%. Patients with s-/t-AML (P = 0·01) and those with complex karyotype (P = 0·04) had an inferior prognosis. Allogeneic haematopoietic cell transplantation (allo-HCT) was performed in 21 (36%) patients, including 15 in first complete remission (CR1). Allo-HCT in CR1 significantly improved survival (P = 0·04); multivariable analysis revealed that allo-HCT in CR1 was effective in de novo AML but not in patients with s-AML/t-AML and less in patients exhibiting a complex karyotype. In summary, outcomes of patients with t(8;16) are dismal with chemotherapy, and may be substantially improved with allo-HCT performed in CR1.

Molecular MRD status and outcome after transplantation in NPM1-mutated AML.

Relapse remains the most common cause of treatment failure for patients with acute myeloid leukemia (AML) who undergo allogeneic stem cell transplantation (alloSCT), and carries a grave prognosis. Multiple studies have identified the presence of measurable residual disease (MRD) assessed by flow cytometry before alloSCT as a strong predictor of relapse, but it is not clear how these findings apply to patients who test positive in molecular MRD assays, which have far greater sensitivity. We analyzed pretransplant blood and bone marrow samples by reverse-transcription polymerase chain reaction in 107 patients with NPM1-mutant AML enrolled in the UK National Cancer Research Institute AML17 study. After a median follow-up of 4.9 years, patients with negative, low (<200 copies per 105ABL in the peripheral blood and <1000 copies in the bone marrow aspirate), and high levels of MRD had an estimated 2-year overall survival (2y-OS) of 83%, 63%, and 13%, respectively (P < .0001). Focusing on patients with low-level MRD before alloSCT, those with FLT3 internal tandem duplications(ITDs) had significantly poorer outcome (hazard ratio [HR], 6.14; P = .01). Combining these variables was highly prognostic, dividing patients into 2 groups with 2y-OS of 17% and 82% (HR, 13.2; P < .0001). T-depletion was associated with significantly reduced survival both in the entire cohort (2y-OS, 56% vs 96%; HR, 3.24; P = .0005) and in MRD-positive patients (2y-OS, 34% vs 100%; HR, 3.78; P = .003), but there was no significant effect of either conditioning regimen or donor source on outcome. Registered at ISRCTN (http://www.isrctn.com/ISRCTN55675535).

Allogeneic hematopoietic cell transplantation improves outcome of adults with t(6;9) acute myeloid leukemia: results from an international collaborative study.

Acute myeloid leukemia (AML) with t(6;9)(p22;q34) is a distinct entity accounting for 1-2% of AML cases. A substantial proportion of these patients have a concomitant FLT3-ITD. While outcomes are dismal with intensive chemotherapy, limited evidence suggests allogeneic hematopoietic cell transplantation (allo-HCT) may improve survival if performed early during first complete remission. We report on a cohort of 178 patients with t(6;9)(p22;q34) within an international, multicenter collaboration. Median age was 46 years (range: 16-76), AML was de novo in 88%, FLT3-ITD was present in 62%, and additional cytogenetic abnormalities in 21%. Complete remission was achieved in 81% (n=144), including 14 patients who received high-dose cytarabine after initial induction failure. With a median follow up of 5.43 years, estimated overall survival at five years was 38% (95%CI: 31-47%). Allo-HCT was performed in 117 (66%) patients, including 89 in first complete remission. Allo-HCT in first complete remission was associated with higher 5-year relapse-free and overall survival as compared to consolidation chemotherapy: 45% (95%CI: 35-59%) and 53% (95%CI: 42-66%) versus 7% (95%CI: 3-19%) and 23% (95%CI: 13-38%), respectively. For patients undergoing allo-HCT, there was no difference in overall survival rates at five years according to whether it was performed in first [53% (95%CI: 42-66%)], or second [58% (95%CI: 31-100%); n=10] complete remission or with active disease/relapse [54% (95%CI: 34-84%); n=18] (P=0.67). Neither FLT3-ITD nor additional chromosomal abnormalities impacted survival. In conclusion, outcomes of t(6;9)(p22;q34) AML are poor with chemotherapy, and can be substantially improved with allo-HCT.

Correction: High expression of HMGA2 independently predicts poor clinical outcomes in acute myeloid leukemia.

Since the publication of the original article the authors noticed the the affiliation details for Paresh Vyas are incorrect. The correct affiliation details for this author are given below.

High expression of HMGA2 independently predicts poor clinical outcomes in acute myeloid leukemia.

In acute myeloid leukemia (AML), risk stratification based on cytogenetics and mutation profiling is essential but remains insufficient to select the optimal therapy. Accurate biomarkers are needed to improve prognostic assessment. We analyzed RNA sequencing and survival data of 430 AML patients and identified HMGA2 as a novel prognostic marker. We validated a quantitative PCR test to study the association of HMGA2 expression with clinical outcomes in 358 AML samples. In this training cohort, HMGA2 was highly expressed in 22.3% of AML, mostly in patients with intermediate or adverse cytogenetics. High expression levels of HMGA2 (H + ) were associated with a lower frequency of complete remission (58.8% vs 83.4%, P < 0.001), worse 3-year overall survival (OS, 13.2% vs 43.5%, P < 0.001) and relapse-free survival (RFS, 10.8% vs 44.2%, P < 0.001). A positive HMGA2 test also identified a subgroup of patients unresponsive to standard treatments. Multivariable analyses showed that H + was independently associated with significantly worse OS and RFS, including in the intermediate cytogenetic risk category. These associations were confirmed in a validation cohort of 260 patient samples from the UK NCRI AML17 trial. The HMGA2 test could be implemented in clinical trials developing novel therapeutic strategies for high-risk AML.

Risk-adapted treatment of acute promyelocytic leukemia: results from the International Consortium for Childhood APL.

Pediatric acute promyelocytic leukemia (APL) can be cured with all-trans retinoic acid (ATRA) and anthracycline. However, most published trials have employed high cumulative doses of anthracyclines. Here, we report the outcome of newly diagnosed APL patients enrolled in the International Consortium for Childhood APL (ICC-APL-01) trial, which reduced anthracycline exposure but extended that of ATRA. The study recruited 258 children/adolescents with molecularly/cytogenetically proven APL. Patients were stratified into standard-risk (SR) and high-risk (HR) groups according to baseline white blood cell counts (<10 × 109/L or ≥10 × 109/L); both groups received identical induction treatment with ATRA and 3 doses of idarubicin. Two or 3 blocks of consolidation therapy were administered to SR and HR patients, respectively, while maintenance therapy with low-dose chemotherapy and ATRA cycles was given to all patients for 2 years. The cumulative dose of daunorubicin equivalent anthracyclines in SR and HR patients was lower than that of previous studies (355 mg/m2 and 405 mg/m2, respectively). Hematologic remission was obtained in 97% of patients; 8 children died of intracranial hemorrhage in the first 2 weeks following diagnosis. Five-year overall and event-free survival for the whole cohort were 94.6% and 79.9%, respectively; they were 98.4% and 89.4% in SR patients and 84.3% and 74.2% in HR patients (P = .002 and P = .043, respectively). These data demonstrate that extended use of ATRA coupled to a risk-adapted consolidation can achieve high cure rates in childhood APL and limit anthracycline exposure. The trial was registered at www.clinicaltrials.gov as EudractCT 2008-002311-40.

Measurable Residual Disease at Induction Redefines Partial Response in Acute Myeloid Leukemia and Stratifies Outcomes in Patients at Standard Risk Without NPM1 Mutations.

Purpose We investigated the effect on outcome of measurable or minimal residual disease (MRD) status after each induction course to evaluate the extent of its predictive value for acute myeloid leukemia (AML) risk groups, including NPM1 wild-type (wt) standard risk, when incorporated with other induction response criteria. Methods As part of the NCRI AML17 trial, 2,450 younger adult patients with AML or high-risk myelodysplastic syndrome had prospective multiparameter flow cytometric MRD (MFC-MRD) assessment. After course 1 (C1), responses were categorized as resistant disease (RD), partial remission (PR), and complete remission (CR) or complete remission with absolute neutrophil count < 1,000/µL or thrombocytopenia < 100,000/µL (CRi) by clinicians, with CR/CRi subdivided by MFC-MRD assay into MRD+ and MRD-. Patients without high-risk factors, including Flt3 internal tandem duplication wt/- NPM1-wt subgroup, received a second daunorubicin/cytosine arabinoside induction; course 2 (C2) was intensified for patients with high-risk factors. Results Survival outcomes from PR and MRD+ responses after C1 were similar, particularly for good- to standard-risk subgroups (5-year overall survival [OS], 27% RD v 46% PR v 51% MRD+ v 70% MRD-; P < .001). Adjusted analyses confirmed significant OS differences between C1 RD versus PR/MRD+ but not PR versus MRD+. CRi after C1 reduced OS in MRD+ (19% CRi v 45% CR; P = .001) patients, with a smaller effect after C2. The prognostic effect of C2 MFC-MRD status (relapse: hazard ratio [HR], 1.88 [95% CI, 1.50 to 2.36], P < .001; survival: HR, 1.77 [95% CI, 1.41 to 2.22], P < .001) remained significant when adjusting for C1 response. MRD positivity appeared less discriminatory in poor-risk patients by stratified analyses. For the NPM1-wt standard-risk subgroup, C2 MRD+ was significantly associated with poorer outcomes (OS, 33% v 63% MRD-, P = .003; relapse incidence, 89% when MRD+ ≥ 0.1%); transplant benefit was more apparent in patients with MRD+ (HR, 0.72; 95% CI, 0.31 to 1.69) than those with MRD- (HR, 1.68 [95% CI, 0.75 to 3.85]; P = .16 for interaction). Conclusion MFC-MRD can improve outcome stratification by extending the definition of partial response after first induction and may help predict NPM1-wt standard-risk patients with poor outcome who benefit from transplant in the first CR.

Minimal/measurable residual disease in AML: a consensus document from the European LeukemiaNet MRD Working Party.

Measurable residual disease (MRD; previously termed minimal residual disease) is an independent, postdiagnosis, prognostic indicator in acute myeloid leukemia (AML) that is important for risk stratification and treatment planning, in conjunction with other well-established clinical, cytogenetic, and molecular data assessed at diagnosis. MRD can be evaluated using a variety of multiparameter flow cytometry and molecular protocols, but, to date, these approaches have not been qualitatively or quantitatively standardized, making their use in clinical practice challenging. The objective of this work was to identify key clinical and scientific issues in the measurement and application of MRD in AML, to achieve consensus on these issues, and to provide guidelines for the current and future use of MRD in clinical practice. The work was accomplished over 2 years, during 4 meetings by a specially designated MRD Working Party of the European LeukemiaNet. The group included 24 faculty with expertise in AML hematopathology, molecular diagnostics, clinical trials, and clinical medicine, from 19 institutions in Europe and the United States.

Pml nuclear body disruption cooperates in APL pathogenesis and impairs DNA damage repair pathways in mice.

A hallmark of acute promyelocytic leukemia (APL) is altered nuclear architecture, with disruption of promyelocytic leukemia (PML) nuclear bodies (NBs) mediated by the PML-retinoic acid receptor α (RARα) oncoprotein. To address whether this phenomenon plays a role in disease pathogenesis, we generated a knock-in mouse model with NB disruption mediated by 2 point mutations (C62A/C65A) in the Pml RING domain. Although no leukemias developed in PmlC62A/C65A mice, these transgenic mice also expressing RARα linked to a dimerization domain (p50-RARα model) exhibited a doubling in the rate of leukemia, with a reduced latency period. Additionally, we found that response to targeted therapy with all-trans retinoic acid in vivo was dependent on NB integrity. PML-RARα is recognized to be insufficient for development of APL, requiring acquisition of cooperating mutations. We therefore investigated whether NB disruption might be mutagenic. Compared with wild-type cells, primary PmlC62A/C65A cells exhibited increased sister-chromatid exchange and chromosome abnormalities. Moreover, functional assays showed impaired homologous recombination (HR) and nonhomologous end-joining (NHEJ) repair pathways, with defective localization of Brca1 and Rad51 to sites of DNA damage. These data directly demonstrate that Pml NBs are critical for DNA damage responses, and suggest that Pml NB disruption is a central contributor to APL pathogenesis.

The Cks1/Cks2 axis fine-tunes Mll1 expression and is crucial for MLL-rearranged leukaemia cell viability.

The Cdc28 protein kinase subunits, Cks1 and Cks2, play dual roles in Cdk-substrate specificity and Cdk-independent protein degradation, in concert with the E3 ubiquitin ligase complexes SCFSkp2 and APCCdc20. Notable targets controlled by Cks include p27 and Cyclin A. Here, we demonstrate that Cks1 and Cks2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together, the Cks proteins define Mll1 levels throughout the cell cycle. Overexpression of CKS1B and CKS2 is observed in multiple human cancers, including various MLL-rearranged (MLLr) AML subtypes. To explore the importance of MLL-Fusion Protein regulation by CKS1/2, we used small molecule inhibitors (MLN4924 and C1) to modulate their protein degradation functions. These inhibitors specifically reduced the proliferation of MLLr cell lines compared to primary controls. Altogether, this study uncovers a novel regulatory pathway for MLL1, which may open a new therapeutic approach to MLLr leukaemia.

A PML/Slit Axis Controls Physiological Cell Migration and Cancer Invasion in the CNS.

Cell migration through the brain parenchyma underpins neurogenesis and glioblastoma (GBM) development. Since GBM cells and neuroblasts use the same migratory routes, mechanisms underlying migration during neurogenesis and brain cancer pathogenesis may be similar. Here, we identify a common pathway controlling cell migration in normal and neoplastic cells in the CNS. The nuclear scaffold protein promyelocytic leukemia (PML), a regulator of forebrain development, promotes neural progenitor/stem cell (NPC) and neuroblast migration in the adult mouse brain. The PML pro-migratory role is active also in transformed mouse NPCs and in human primary GBM cells. In both normal and neoplastic settings, PML controls cell migration via Polycomb repressive complex 2 (PRC2)-mediated repression of Slits, key regulators of axon guidance. Finally, a PML/SLIT1 axis regulates sensitivity to the PML-targeting drug arsenic trioxide in primary GBM cells. Taken together, these findings uncover a drug-targetable molecular axis controlling cell migration in both normal and neoplastic cells.

Clinical impact of BAALC expression in high-risk acute promyelocytic leukemia.

Although overexpression of the brain and acute leukemia, cytoplasmic (BAALC) gene is associated with primary resistant disease and shorter relapse-free, disease-free, and overall survival in different subsets of acute myeloid leukemia (AML), little is known about its clinical impact in acute promyelocytic leukemia (APL). Using real-time reverse transcriptase polymerase chain reaction, we showed that BAALC expression is significantly lower in APL compared with other subsets of AML (P < .001). We also demonstrated that BAALC overexpression was associated with shorter disease-free survival (DFS) (hazard ratio [HR], 4.43; 95% confidence interval [CI], 1.29-15.2; P = .018) in 221 consecutive patients (median age, 35 years; range, 18-82 years) with newly diagnosed APL homogeneously treated with all-trans retinoic acid and anthracycline-based chemotherapy. Cox proportional hazard modeling showed that BAALC overexpression was independently associated with shorter DFS in the total cohort (HR, 5.26; 95% CI, 1.52-18.2; P = .009) and in patients with high-risk disease (ie, those with initial leukocyte counts >10 × 109/L) (HR, 5.3; 95% CI, 1.14-24.5; P = .033). We conclude that BAALC expression could be useful for refining risk stratification in APL, although this needs to be confirmed in independent cohorts.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel.

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

Normal Hematopoietic Progenitor Subsets Have Distinct Reactive Oxygen Species, BCL2 and Cell-Cycle Profiles That Are Decoupled from Maturation in Acute Myeloid Leukemia.

In acute myeloid leukemia (AML) quiescence and low oxidative state, linked to BCL2 mitochondrial regulation, endow leukemic stem cells (LSC) with treatment-resistance. LSC in CD34+ and more mature CD34- AML have heterogeneous immunophenotypes overlapping with normal stem/progenitor cells (SPC) but may be differentiated by functional markers. We therefore investigated the oxidative/reactive oxygen species (ROS) profile, its relationship with cell-cycle/BCL2 for normal SPC, and whether altered in AML and myelodysplasia (MDS). In control BM (n = 24), ROS levels were highest in granulocyte-macrophage progenitors (GMP) and CD34- myeloid precursors but megakaryocyte-erythroid progenitors had equivalent levels to CD34+CD38low immature-SPC although they were ki67high. BCL2 upregulation was specific to GMPs. This profile was also observed for CD34+SPC in MDS-without-excess-blasts (MDS-noEB, n = 12). Erythroid CD34- precursors were, however, abnormally ROS-high in MDS-noEB, potentially linking oxidative stress to cell loss. In pre-treatment AML (n = 93) and MDS-with-excess-blasts (MDS-RAEB) (n = 14), immunophenotypic mature-SPC had similar ROS levels to co-existing immature-SPC. However ROS levels varied between AMLs; Flt3ITD+/NPM1wild-type CD34+SPC had higher ROS than NPM1mutated CD34+ or CD34- SPC. An aberrant ki67lowBCL2high immunophenotype was observed in CD34+AML (most prominent in Flt3ITD AMLs) but also in CD34- AMLs and MDS-RAEB, suggesting a shared redox/pro-survival adaptation. Some patients had BCL2 overexpression in CD34+ ROS-high as well as ROS-low fractions which may be indicative of poor early response to standard chemotherapy. Thus normal SPC subsets have distinct ROS, cell-cycle, BCL2 profiles that in AML /MDS-RAEB are decoupled from maturation. The combined profile of these functional properties in AML subpopulations may be relevant to differential treatment resistance.