Serum Free Light Chain Kinetics Is Predictive of Renal Response in Myeloma Patients With Renal Impairment-An ALLG Trial of Carfilzomib-Dexamethasone Therapy in Frontline and Relapse.

BACKGROUND AND PURPOSE: Renal impairment (RI) confers adverse prognosis in myeloma; its reversal and avoidance of dialysis are crucial. We investigated whether serum free light chain (SFLC) measurements can predict renal outcome, to enable change in therapy to optimize prognosis and avoid dialysis. PATIENTS AND METHODS: We investigated 36 myeloma patients (17 newly diagnosed [ND]; 19 relapsed refractory [RR]; with median of 5 prior lines) with eGFR 15-40 ml/min treated with carfilzomib (Cfz)-dexamethasone to determine whether SFLC kinetics can predict renal outcomes, and assess efficacy and tolerability. RESULTS: The change in involved SFLC at Cycle 2 Day 1 was significantly correlated with renal function; for every one log10 reduction in involved SFLC, eGFR increased by 9.0-15.0 mL/min at cycles 2-4, with SFLC reduction of 54%-78%. At a median follow-up of 30.6 months, renal outcomes were favorable-CRrenal 25%, MRrenal 36%. Disease responses (ND 100%, RR 75%), progression-free survival (ND 32.2 months, RR 11.1 months) and overall survival (ND not reached, RR 42.0 months) were comparable to patients without RI. There was significant toxicity, including Cfz-related cardiac impairment of 20% within a cohort with high co-morbidity, and a high incidence of infections. CONCLUSION: We propose that one log10 reduction in involved SFLC at Cycle 2 Day 1 is an appropriate target for reducing the risk of dialysis in myeloma patients with RI; below this threshold patients may benefit from a change in therapy. While Cfz-dexamethasone achieved favorable renal and disease outcomes, toxicity can be significant in this vulnerable cohort.

Combining 5-azacitidine with the E-selectin antagonist uproleselan is an effective strategy to augment responses in myelodysplasia and acute myeloid leukaemia.

The interaction of acute myeloid leukaemic (AML) blasts with the bone marrow (BM) microenvironment is a major determinant governing disease progression and resistance to treatment. The constitutive expression of E-selectin in the vascular compartment of BM, a key endothelial cell factor, directly mediates chemoresistance via E-selectin ligand/receptors. Despite the success of hypomethylating agent (HMA)-containing regimens to induce remissions in older AML patients, the development of primary or secondary resistance is common. We report that following treatment with 5-azacitidine, promoter regions regulating the biosynthesis of the E-selectin ligands, sialyl Lewis X, become further hypomethylated. The resultant upregulation of these gene products, in particular α(1,3)-fucosyltransferase VII (FUT7) and α(2,3)-sialyltransferase IV (ST3GAL4), likely causes functional E-selectin binding. When combined with the E-selectin antagonist uproleselan, the adhesion to E-selectin is reversed and the survival of mice transplanted with AML cells is prolonged. Finally, we present clinical evidence showing that BM myeloid cells from higher risk MDS and AML patients have the potential to bind E-selectin, and these cells are more abundant in 5-azacitidine-non-responsive patients. The collective data provide a strong rationale to evaluate 5-azacitidine in combination with the E-selectin antagonist, uproleselan, in this patient population.

High Expression of ENO1 and Low Levels of Circulating Anti-ENO1 Autoantibodies in Patients with Myelodysplastic Neoplasms and Acute Myeloid Leukaemia.

In solid tumours, high expression of the glycolytic enzyme, α-enolase (ENO1), predicts for poor patient overall survival (OS), and circulating autoantibodies to ENO1 correlate positively with diagnosis and negatively with advanced disease. Although ENO1 is one of the most highly expressed genes in acute myeloid leukaemia (AML), its potential role as a biomarker in AML or its precursor, myelodysplastic neoplasms (MDS), has not been investigated. A meta-analysis of nine AML online datasets (n = 1419 patients) revealed that high ENO1 expression predicts for poor OS (HR = 1.22, 95% CI: 1.10-1.34, p < 0.001). Additionally, when compared to AML in remission (n = 5), ENO1 protein detected by immunohistochemistry was significantly higher at diagnosis in bone marrow from both AML (n = 5, p < 0.01) and MDS patients (n = 12, p < 0.05), and did not correlate with percentage of blasts (r = 0.28, p = 0.21). AML patients (n = 34) had lower circulating levels of ENO1 autoantibodies detected by ELISA compared to 26 MDS and 18 controls (p = 0.003). However, there was no difference in OS between AML patients with high vs. low levels of anti-ENO1 autoantibodies (p = 0.77). BM immunostaining for ENO1 and patient monitoring of anti-ENO1 autoantibody levels may be useful biomarkers for MDS and AML.

A comparative evaluation of three consecutive artificial intelligence algorithms released by Techcyte for identification of blasts and white blood cells in abnormal peripheral blood films.

INTRODUCTION: Digital pathology artificial intelligence (AI) platforms have the capacity to improve over time through "deep machine learning." We have previously reported on the accuracy of peripheral white blood cell (WBC) differential and blast identification by Techcyte (Techcyte, Inc., Orem, UT, USA), a digital scanner-agnostic web-based system for blood film reporting. The aim of the current study was to compare AI protocols released over time to assess improvement in cell identification. METHODS: WBC differentials were performed using Techcyte's online AI software on the same 124 digitized abnormal peripheral blood films (including 64 acute and 22 chronic leukaemias) in 2019 (AI1), 2020 (AI2), and 2022 (AI3), with no reassignment by a morphologist at any time point. AI results were correlated to the "gold standard" of manual microscopy, and comparison of Lin's concordance coefficients (LCC) and sensitivity and specificity of blast identification were used to determine the superior AI version. RESULTS: AI correlations (r) with manual microscopy for individual cell types ranged from 0.50-0.90 (AI1), 0.66-0.86 (AI2) and 0.71-0.91 (AI3). AI3 concordance with manual microscopy was significantly improved compared to AI1 for identification of neutrophils (LCC AI3 = 0.86 vs. AI1 = 0.77, p = 0.03), total granulocytes (LCC AI3 = 0.92 vs. AI1 = 0.82, p = 0.0008), immature granulocytes (LCC AI3 = 0.67 vs. AI1 = 0.38, p = 0.0014), and promyelocytes (LCC AI3 = 0.53 vs. AI1 = 0.16, p = 0.0008). Sensitivity for blast identification (n = 65 slides) improved from 97% (AI1), to 98% (AI2), to 100% (AI3), while blast specificity decreased from 24% (AI1), to 14% (AI2) to 12% (AI3). CONCLUSION: Techcyte AI has shown significant improvement in cell identification over time and maintains high sensitivity for blast identification in malignant films.

Australia and New Zealand consensus position statement: use of COVID-19 therapeutics in patients with haematological malignancies.

Despite widespread vaccination rates, we are living with high transmission rates of SARS-CoV-2. Although overall hospitalisation rates are falling, the risk of serious infection remains high for patients who are immunocompromised because of haematological malignancies. In light of the ongoing pandemic and the development of multiple agents for treatment, representatives from the Haematology Society of Australia and New Zealand and infectious diseases specialists have collaborated on this consensus position statement regarding COVID-19 management in patients with haematological disorders. It is our recommendation that both patients with haematological malignancies and treating specialists be educated regarding the preventive and treatment options available and that patients continue to receive adequate vaccinations, keeping in mind the suboptimal vaccine responses that occur in haematology patients, in particular, those with B-cell malignancies and on B-cell-targeting or depleting therapy. Patients with haematological malignancies should receive treatment for COVID-19 in accordance with the severity of their symptoms, but even mild infections should prompt early treatment with antiviral agents. The issue of de-isolation following COVID-19 infection and optimal time to treatment for haematological malignancies is discussed but remains an area with evolving data. This position statement is to be used in conjunction with advice from infectious disease, respiratory and intensive care specialists, and current guidelines from the National COVID-19 Clinical Evidence Taskforce and the New Zealand Ministry of Health and Cancer Agency Te Aho o Te Kahu COVID-19 Guidelines.

Crosstalk between DNA methylation and hypoxia in acute myeloid leukaemia.

BACKGROUND: Acute myeloid leukaemia (AML) is a deadly disease characterised by the uncontrolled proliferation of immature myeloid cells within the bone marrow. Altered regulation of DNA methylation is an important epigenetic driver of AML, where the hypoxic bone marrow microenvironment can help facilitate leukaemogenesis. Thus, interactions between epigenetic regulation and hypoxia signalling will have important implications for AML development and treatment. MAIN BODY: This review summarises the importance of DNA methylation and the hypoxic bone marrow microenvironment in the development, progression, and treatment of AML. Here, we focus on the role hypoxia plays on signalling and the subsequent regulation of DNA methylation. Hypoxia is likely to influence DNA methylation through altered metabolic pathways, transcriptional control of epigenetic regulators, and direct effects on the enzymatic activity of epigenetic modifiers. DNA methylation may also prevent activation of hypoxia-responsive genes, demonstrating bidirectional crosstalk between epigenetic regulation and the hypoxic microenvironment. Finally, we consider the clinical implications of these interactions, suggesting that reduced cell cycling within the hypoxic bone marrow may decrease the efficacy of hypomethylating agents. CONCLUSION: Hypoxia is likely to influence AML progression through complex interactions with DNA methylation, where the therapeutic efficacy of hypomethylating agents may be limited within the hypoxic bone marrow. To achieve optimal outcomes for AML patients, future studies should therefore consider co-treatments that can promote cycling of AML cells within the bone marrow or encourage their dissociation from the bone marrow.

Sorafenib plus intensive chemotherapy in newly diagnosed FLT3-ITD AML: a randomized, placebo-controlled study by the ALLG.

Sorafenib maintenance improves outcomes after hematopoietic cell transplant (HCT) for patients with FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) acute myeloid leukemia (AML). Although promising outcomes have been reported for sorafenib plus intensive chemotherapy, randomized data are limited. This placebo-controlled, phase 2 study (ACTRN12611001112954) randomized 102 patients (aged 18-65 years) 2:1 to sorafenib vs placebo (days 4-10) combined with intensive induction: idarubicin 12 mg/m2 on days 1 to 3 plus either cytarabine 1.5 g/m2 twice daily on days 1, 3, 5, and 7 (18-55 years) or 100 mg/m2 on days 1 to 7 (56-65 years), followed by consolidation and maintenance therapy for 12 months (post-HCT excluded) in newly diagnosed patients with FLT3-ITD AML. Four patients were excluded in a modified intention-to-treat final analysis (3 not commencing therapy and 1 was FLT3-ITD negative). Rates of complete remission (CR)/CR with incomplete hematologic recovery were high in both arms (sorafenib, 78%/9%; placebo, 70%/24%). With 49.1-months median follow-up, the primary end point of event-free survival (EFS) was not improved by sorafenib (2-year EFS 47.9% vs 45.4%; hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.51-1.51; P = .61). Two-year overall survival (OS) was 67% in the sorafenib arm and 58% in the placebo arm (HR, 0.76; 95% CI, 0.42-1.39). For patients who received HCT in first remission, the 2-year OS rates were 84% and 67% in the sorafenib and placebo arms, respectively (HR, 0.45; 95% CI, 0.18-1.12; P = .08). In exploratory analyses, FLT3-ITD measurable residual disease (MRD) negative status (<0.001%) after induction was associated with improved 2-year OS (83% vs 60%; HR, 0.4; 95% CI, 0.17-0.93; P = .028). In conclusion, routine use of pretransplant sorafenib plus chemotherapy in unselected patients with FLT3-ITD AML is not supported by this study.

Blockade of ROS production inhibits oncogenic signaling in acute myeloid leukemia and amplifies response to precision therapies.

Mutations in the type III receptor tyrosine kinase FLT3 are frequent in patients with acute myeloid leukemia (AML) and are associated with a poor prognosis. AML is characterized by the overproduction of reactive oxygen species (ROS), which can induce cysteine oxidation in redox-sensitive signaling proteins. Here, we sought to characterize the specific pathways affected by ROS in AML by assessing oncogenic signaling in primary AML samples. The oxidation or phosphorylation of signaling proteins that mediate growth and proliferation was increased in samples from patient subtypes with FLT3 mutations. These samples also showed increases in the oxidation of proteins in the ROS-producing Rac/NADPH oxidase-2 (NOX2) complex. Inhibition of NOX2 increased the apoptosis of FLT3-mutant AML cells in response to FLT3 inhibitors. NOX2 inhibition also reduced the phosphorylation and cysteine oxidation of FLT3 in patient-derived xenograft mouse models, suggesting that decreased oxidative stress reduces the oncogenic signaling of FLT3. In mice grafted with FLT3 mutant AML cells, treatment with a NOX2 inhibitor reduced the number of circulating cancer cells, and combining FLT3 and NOX2 inhibitors increased survival to a greater extent than either treatment alone. Together, these data raise the possibility that combining NOX2 and FLT3 inhibitors could improve the treatment of FLT3 mutant AML.

Panel-based gene testing in myelodysplastic/myeloproliferative neoplasm overlap syndromes: Australasian Leukaemia and Lymphoma Group (ALLG) consensus statement.

This review aims to provide an expert consensus statement to address the role of gene-panel testing in the diagnosis, prognosis and management of adult myelodysplastic syndrome/myeloproliferative neoplasm overlap syndromes (MDS/MPN) in Australia. This consensus statement was developed by an expert group, actively involved in gene panel testing in the area of MDS/MPN in Australia. This work was led by the chairs of the MDS (A/Prof A. Enjeti) and MPN (A/Prof D. Ross) working parties of the Australasian Leukaemia and Lymphoma Group (ALLG). The authors were selected after an expression of interest process on the basis of active laboratory involvement in gene panel testing, a specific demonstrated interest in MDS/MPN and/or publication record in this field. The authors were then allocated sections for literature review to identify the specific genes of interest for each MDS/MPN entity. At least two authors reviewed each section and an overarching diagnostic algorithm was developed by a consensus amongst all authors.

scTEM-seq: Single-cell analysis of transposable element methylation to link global epigenetic heterogeneity with transcriptional programs.

Global changes in DNA methylation are observed in development and disease, and single-cell analyses are highlighting the heterogeneous regulation of these processes. However, technical challenges associated with single-cell analysis of DNA methylation limit these studies. We present single-cell transposable element methylation sequencing (scTEM-seq) for cost-effective estimation of average DNA methylation levels. By targeting high-copy SINE Alu elements, we achieve amplicon bisulphite sequencing with thousands of loci covered in each scTEM-seq library. Parallel transcriptome analysis is also performed to link global DNA methylation estimates with gene expression. We apply scTEM-seq to KG1a acute myeloid leukaemia (AML) cells, and primary AML cells. Our method reveals global DNA methylation heterogeneity induced by decitabine treatment of KG1a cells associated with altered expression of immune process genes. We also compare global DNA methylation estimates to expression of transposable elements and find a predominance of negative correlations. Finally, we observe co-ordinated upregulation of many transposable elements in a sub-set of decitabine treated cells. By linking global DNA methylation heterogeneity with transcription, scTEM-seq will refine our understanding of epigenetic regulation in cancer and beyond.

Consensus guidelines for the management of adult immune thrombocytopenia in Australia and New Zealand.

INTRODUCTION: The absence of high quality evidence for basic clinical dilemmas in immune thrombocytopenic purpura (ITP) underlines the need for contemporary guidelines relevant to the local treatment context. ITP is diagnosed by exclusions, with a hallmark laboratory finding of isolated thrombocytopenia. MAIN RECOMMENDATIONS: Bleeding, family and medication histories and a review of historical investigations are required to gauge the bleeding risk and possible hereditary syndromes. Beyond the platelet count, the decision to treat is affected by individual bleeding risk, disease stage, side effects of treatment, concomitant medications, and patient preference. Treatment is aimed at achieving a platelet count > 20 × 109 /L, and avoidance of severe bleeding. Steroids are the standard first line treatment, with either 6-week courses of tapering prednisone or repeated courses of high dose dexamethasone providing equivalent efficacy. Intravenous immunoglobulin can be used periprocedurally or as first line therapy in combination with steroids. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: There is no consensus on choice of second line treatments. Options with the most robust evidence include splenectomy, rituximab and thrombopoietin receptor agonists. Other therapies include azathioprine, mycophenolate mofetil, dapsone and vinca alkaloids. Given that up to one-third of patients achieve a satisfactory haemostatic response, splenectomy should be delayed for at least 12 months if possible. In life-threatening bleeding, we recommend platelet transfusions to achieve haemostasis, along with intravenous immunoglobulin and high dose steroids.

Risk-benefit analysis of the AstraZeneca COVID-19 vaccine in Australia using a Bayesian network modelling framework.

Thrombosis and Thrombocytopenia Syndrome (TTS) has been associated with the AstraZencea (AZ) COVID-19 vaccine (Vaxzevria). Australia has reported low TTS incidence of < 3/100,000 after the first dose, with case fatality rate (CFR) of 5-6%. Risk-benefit analysis of vaccination has been challenging because of rapidly evolving data, changing levels of transmission, and variation in rates of TTS, COVID-19, and CFR between age groups. We aim to optimise risk-benefit analysis by developing a model that enables inputs to be updated rapidly as evidence evolves. A Bayesian network was used to integrate local and international data, government reports, published literature and expert opinion. The model estimates probabilities of outcomes under different scenarios of age, sex, low/medium/high transmission (0.05%/0.45%/5.76% of population infected over 6 months), SARS-CoV-2 variant, vaccine doses, and vaccine effectiveness. We used the model to compare estimated deaths from AZ vaccine-associated TTS with i) COVID-19 deaths prevented under different scenarios, and ii) deaths from COVID-19 related atypical severe blood clots (cerebral venous sinus thrombosis & portal vein thrombosis). For a million people aged ≥ 70 years where 70% received first dose and 35% received two doses, our model estimated < 1 death from TTS, 25 deaths prevented under low transmission, and > 3000 deaths prevented under high transmission. Risks versus benefits varied significantly between age groups and transmission levels. Under high transmission, deaths prevented by AZ vaccine far exceed deaths from TTS (by 8 to > 4500 times depending on age). Probability of dying from COVID-related atypical severe blood clots was 58-126 times higher (depending on age and sex) than dying from TTS. To our knowledge, this is the first example of the use of Bayesian networks for risk-benefit analysis for a COVID-19 vaccine. The model can be rapidly updated to incorporate new data, adapted for other countries, extended to other outcomes (e.g., severe disease), or used for other vaccines.

White blood cell evaluation in haematological malignancies using a web-based digital microscopy platform.

INTRODUCTION: Digital microscopy systems are beginning to replace traditional light microscopes for morphologic analysis of blood films, but these are geographically restricted to individual computers and technically limited by manufacturer's constraints. We explored the use of a scanner-agnostic web-based artificial intelligence (AI) system to assess the accuracy of white blood cell (WBC) differentials and blast identification in haematological malignancies. METHODS: Digitized images of 20 normal and 124 abnormal peripheral blood films were uploaded to the web-based platform (Techcyte©) and WBC differentials performed using the online AI software. Digital images were viewed for accuracy and manual cell reassignment was performed where necessary. Results were correlated to the 'gold standard' of manual microscopy for each WBC class, and sensitivity and specificity of blast identification were calculated. RESULTS: The AI digital differential was very strongly correlated to microscopy (r > .8) for most normal cell types and did not require any manual reassignment. The AI digital differential was less reliable for abnormal blood films (r = .50-.87), but could be greatly improved by manual assessment of digital images for most cell types (r > .95) with the exception of immature granulocytes (r = .62). For blast identification, initial AI digital differentials showed 96% sensitivity and 25% specificity, which was improved to 99% and 84%, respectively, after manual digital review. CONCLUSIONS: The Techcyte platform allowed remote viewing and manual analysis of digitized slides that was comparable to microscopy. The AI software produced adequate WBC differentials for normal films and had high sensitivity for blast identification in malignant films.

COVID-19 vaccination in haematology patients: an Australian and New Zealand consensus position statement.

Australia and New Zealand have achieved excellent community control of COVID-19 infection. In light of the imminent COVID-19 vaccination roll out in both countries, representatives from the Haematology Society of Australia and New Zealand and infectious diseases specialists have collaborated on this consensus position statement regarding COVID-19 vaccination in patients with haematological disorders. It is our recommendation that patients with haematological malignancies, and some benign haematological disorders, should have expedited access to high-efficacy COVID-19 vaccines, given that these patients are at high risk of morbidity and mortality from COVID-19 infection. Vaccination should not replace other public health measures in these patients, given that the effectiveness of COVID-19 vaccination, specifically in patients with haematological malignancies, is not known. Given the limited available data, prospective collection of safety and efficacy data of COVID-19 vaccination in this patient group is a priority.

Unravelling the Epigenome of Myelodysplastic Syndrome: Diagnosis, Prognosis, and Response to Therapy.

Myelodysplastic syndrome (MDS) is a malignancy that disrupts normal blood cell production and commonly affects our ageing population. MDS patients are diagnosed using an invasive bone marrow biopsy and high-risk MDS patients are treated with hypomethylating agents (HMAs) such as decitabine and azacytidine. However, these therapies are only effective in 50% of patients, and many develop resistance to therapy, often resulting in bone marrow failure or leukemic transformation. Therefore, there is a strong need for less invasive, diagnostic tests for MDS, novel markers that can predict response to therapy and/or patient prognosis to aid treatment stratification, as well as new and effective therapeutics to enhance patient quality of life and survival. Epigenetic modifiers such as DNA methylation, long non-coding RNAs (lncRNAs) and micro-RNAs (miRNAs) are perturbed in MDS blasts and the bone marrow micro-environment, influencing disease progression and response to therapy. This review focusses on the potential utility of epigenetic modifiers in aiding diagnosis, prognosis, and predicting treatment response in MDS, and touches on the need for extensive and collaborative research using single-cell technologies and multi-omics to test the clinical utility of epigenetic markers for MDS patients in the future.

Single-cell epigenomics in cancer: charting a course to clinical impact.

Cancer is a disease of global epigenetic dysregulation. Mutations in epigenetic regulators are common events in multiple cancer types and epigenetic therapies are emerging as a treatment option in several malignancies. A major challenge for the clinical management of cancer is the heterogeneous nature of this disease. Cancers are composed of numerous cell types and evolve over time. This heterogeneity confounds decisions regarding treatment and promotes disease relapse. The emergence of single-cell epigenomic technologies has introduced the exciting possibility of linking genetic and transcriptional heterogeneity in the context of cancer biology. The next challenge is to leverage these tools for improved patient outcomes. Here we consider how single-cell epigenomic technologies may address the current challenges faced by cancer clinicians.

Genomic investigation of inherited thrombotic microangiopathy-aHUS and TTP.

Thrombotic microangiopathies (TMA) are a heterogeneous group of red cell fragmentation syndromes characterized by a tendency for thrombosis and pathognomonic red cell fragments in peripheral blood, which results in thrombosis in the microvasculature due to endothelial damage. Genomic investigations into inherited TMAs are of diagnostic, prognostic and therapeutic value. Here, we present two cases that capture the importance of performing genomic testing in rare disorders. Treatment options for these conditions, such as plasma exchange and monoclonal antibodies against complement factors, are intensive and expensive health care interventions. The results of genomic investigation into rare TMAs can better inform the clinicians and their patients of prognosis and suitable personalized treatment options.

Enrichment of atypical hyperdiploidy and IKZF1 deletions detected by SNP-microarray in high-risk Australian AIEOP-BFM B-cell acute lymphoblastic leukaemia cohort.

Acute lymphoblastic leukaemia (ALL) is the most common childhood malignancy with the majority of patients being classified as B-cell lineage (B-ALL). The sub-classification of B-ALL is based on genomic architecture. Recent studies have demonstrated the capability of SNP-microarrays to detect genomic changes in B-ALL which cannot be observed by conventional cytogenetic methods. In current clinical trials, B-ALL patients at high risk of relapse are mainly identified by adverse cancer genomics and/or poor response to early therapy. To test the hypothesis that inclusion of SNP-microarrays in frontline diagnostics could more efficiently and accurately identify adverse genomic factors than conventional techniques, we evaluated the Australian high-risk B-ALL cohort enrolled on AIEOP-BFM ALL 2009 study (n = 33). SNP-microarray analysis identified additional aberrations in 97% of patients (32/33) compared to conventional techniques. This changed the genomic risk category of 24% (8/33) of patients. Additionally, 27% (9/33) of patients exhibited a 'hyperdiploid' genome, which is generally associated with a good genomic risk and favourable outcomes. An enrichment of IKZF1 deletions was observed with one third of the cohort affected. Our findings suggest the current classification system could be improved and highlights the need to use more sensitive techniques such as SNP-microarray for cytogenomic risk stratification in B-ALL.