Predicting relapse risk in childhood acute lymphoblastic leukaemia

[Risk factors for recurrence of childhood acute lymphoblastic leukemia after treatment with the Chinese Children's Cancer Group ALL-2015 protocol]

OBJECTIVES

To investigate the cumulative incidence of recurrence (CIR) in children with acute lymphoblastic leukemia (ALL) after treatment with the Chinese Children's Cancer Group ALL-2015 (CCCG-ALL-2015) protocol and the risk factors for recurrence.

METHODS

A retrospective analysis was conducted on the clinical data of 852 children who were treated with the CCCG-ALL-2015 protocol from January 2015 to December 2019. CIR was calculated, and the risk factors for the recurrence of B-lineage acute lymphoblastic leukemia (B-ALL) were analyzed.

RESULTS

Among the 852 children with ALL, 146 (17.1%) experienced recurrence, with an 8-year CIR of 19.8%±1.6%. There was no significant difference in 8-year CIR between the B-ALL group and the acute T lymphocyte leukemia group (P>0.05). For the 146 children with recurrence, recurrence was mainly observed in the very early stage (n=62, 42.5%) and the early stage (n=46, 31.5%), and there were 42 children with bone marrow recurrence alone (28.8%) in the very early stage and 27 children with bone marrow recurrence alone (18.5%) in the early stage. The Cox proportional-hazards regression model analysis showed that positive MLLr fusion gene (HR=4.177, 95%CI: 2.086-8.364, P<0.001) and minimal residual disease≥0.01% on day 46 (HR=2.013, 95%CI: 1.163-3.483, P=0.012) were independent risk factors for recurrence in children with B-ALL after treatment with the CCCG-ALL-2015 protocol.

CONCLUSIONS

There is still a relatively high recurrence rate in children with ALL after treatment with the CCCG-ALL-2015 protocol, mainly bone marrow recurrence alone in the very early stage and the early stage, and minimal residual disease≥0.01% on day 46 and positive MLLr fusion gene are closely associated with the recurrence of B-ALL.

RNA-seq-based miRNA signature as an independent predictor of relapse in pediatric B-cell acute lymphoblastic leukemia

ABSTRACT

Aberrant micro-RNA (miRNA) expression profiles have been associated with disease progression and clinical outcome in pediatric cancers. However, few studies have analyzed genome-wide dysregulation of miRNAs and messenger RNAs (mRNAs) in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). To identify novel prognostic factors, we comprehensively investigated miRNA and mRNA sequencing (miRNA-seq and mRNA-seq) data in pediatric BCP-ALL samples with poor outcome. We analyzed 180 patients, including 43 matched pairs at diagnosis and relapse. Consensus clustering of miRNA expression data revealed a distinct profile characterized by mainly downregulation of miRNAs (referred to as an miR-low cluster [MLC]). The MLC profile was not associated with any known genetic subgroups. Intriguingly, patients classified as MLC had significantly shorter event-free survival (median 21 vs 33 months; log-rank P = 3 ×10-5). Furthermore, this poor prognosis was retained even in hyperdiploid ALL. This poor prognostic MLC profiling was confirmed in the validation cohort. Notably, non-MLC profiling at diagnosis (n = 9 of 23; Fisher exact test, P = .039) often changed into MLC profiling at relapse for the same patient. Integrated analysis of miRNA-seq and mRNA-seq data revealed that the transcriptional profile of MLC was characterized by enrichment of MYC target and oxidative phosphorylation genes, reduced intron retention, and low expression of DICER1. Thus, our miRNA-mRNA integration approach yielded a truly unbiased molecular stratification of pediatric BCP-ALL cases based on a novel prognostic miRNA signature, which may lead to better clinical outcomes.

Nelarabine-containing salvage therapy and conditioning regimen in transplants for pediatric T-cell acute lymphoblastic leukemia and lymphoma

Therapy for relapsed or refractory (r/r) T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in children is challenging, and new treatment methods are needed. We retrospectively analyzed eight patients with r/r T-ALL (five patients) and T-LBL (three patients) who were treated with nelarabine (NEL) plus etoposide, cyclophosphamide, and intrathecal therapy, administered 3 days apart. Five patients achieved a complete response, and the other three achieved a partial response (PR). All patients underwent hematopoietic stem cell transplantation (HSCT) after two cycles of treatment, except for one patient who received one cycle. Three patients who had previously received HSCT were treated with reduced-intensity conditioning regimens, including fludarabine, melphalan, and NEL; one survived for over 5 years after the second HSCT. Grade 2 neuropathy occurred in one patient, but other severe toxicities commonly associated with NEL were not observed during NEL administration in combination with chemotherapy. The 2-year overall survival and event-free survival rates were 60.0% and 36.5%, respectively. The addition of NEL to reinduction chemotherapy was useful in achieving remission and did not lead to excessive toxicity. In addition, a conditioning regimen, including NEL, appeared to be effective in patients who had previously undergone HSCT.

Prognostic implications of CD9 in childhood acute lymphoblastic leukemia: insights from a nationwide multicenter study in China

The outcomes of children with acute lymphoblastic leukemia (ALL) have been incrementally improved with risk-directed chemotherapy but therapy responses remain heterogeneous. Parameters with added prognostic values are warranted to refine the current risk stratification system and inform appropriate therapies. CD9, implicated by our prior single-center study, holds promise as one such parameter. To determine its precise prognostic significance, we analyzed a nationwide, multicenter, uniformly treated cohort of childhood ALL cases, where CD9 status was defined by flow cytometry on diagnostic samples of 3781 subjects. CD9 was expressed in 88.5% of B-ALL and 27.9% of T-ALL cases. It conferred a lower 5-year EFS and a higher CIR in B-ALL but not in T-ALL patients. The prognostic impact of CD9 was most pronounced in the intermediate/high-risk arms and those with minimal residual diseases, particularly at day 19 of remission induction. The adverse impact of CD9 was confined to specific cytogenetics, notably BCR::ABL1+ rather than KMT2A-rearranged leukemia. Multivariate analyses confirmed CD9 as an independent predictor of both events and relapse. The measurement of CD9 offers insights into patients necessitating intervention, warranting its seamless integration into the diagnostic marker panel to inform risk level and timely introduction of therapeutic intervention for childhood ALL.

Transcription factor abnormalities in B-ALL leukemogenesis and treatment

The biological regulation of transcription factors (TFs) and repressor proteins is an important mechanism for maintaining cell homeostasis. In B cell acute lymphoblastic leukemia (B-ALL) TF abnormalities occur at high frequency and are often recognized as the major driving factor in carcinogenesis. We provide an in-depth review of molecular mechanisms of six major TF rearrangements in B-ALL, including DUX4-rearranged (DUX4-R), MEF2D-R, ZNF384-R, ETV6-RUNX1 and TCF3-PBX1 fusions, and KMT2A-R. In addition, the therapeutic options and prognoses for patients who harbor these TF abnormalities are discussed. This review aims to provide an up-to-date panoramic view of how TF-based oncogenic fusions might drive carcinogenesis and impact on potential therapeutic exploration of B-ALL treatments.

Increased MYB alternative promoter usage is associated with relapse in acute lymphoblastic leukemia

Therapy-resistant disease is a major cause of death in patients with acute lymphoblastic leukemia (ALL). Activation of the MYB oncogene is associated with ALL and leads to uncontrolled neoplastic cell proliferation and blocked differentiation. Here, we used RNA-seq to study the clinical significance of MYB expression and MYB alternative promoter (TSS2) usage in 133 pediatric ALLs. RNA-seq revealed that all cases analyzed overexpressed MYB and demonstrated MYB TSS2 activity. qPCR analyses confirmed the expression of the alternative MYB promoter also in seven ALL cell lines. Notably, high MYB TSS2 activity was significantly associated with relapse (p = 0.007). Moreover, cases with high MYB TSS2 usage showed evidence of therapy-resistant disease with increased expression of ABC multidrug resistance transporter genes (e.g., ABCA2, ABCB5, and ABCC10) and enzymes catalyzing drug degradation (e.g., CYP1A2, CYP2C9, and CYP3A5). Elevated MYB TSS2 activity was further associated with augmented KRAS signaling (p < 0.05) and decreased methylation of the conventional MYB promoter (p < 0.01). Taken together, our results suggest that MYB alternative promoter usage is a novel potential prognostic biomarker for relapse and therapy resistance in pediatric ALL.

Functional Characterization of Transforming Growth Factor-β Signaling in Dasatinib Resistance and Pre-BCR+ Acute Lymphoblastic Leukemia

The multi-kinase inhibitor dasatinib has been implicated to be effective in pre-B-cell receptor (pre-BCR)-positive acute lymphoblastic leukemia (ALL) expressing the E2A-PBX1 fusion oncoprotein. The TGFβ signaling pathway is involved in a wide variety of cellular processes, including embryonic development and cell homeostasis, and it can have dual roles in cancer: suppressing tumor growth at early stages and mediating tumor progression at later stages. In this study, we identified the upregulation of the TGFβ signaling pathway in our previously generated human dasatinib-resistant pre-BCR+/E2A-PBX1+ ALL cells using global transcriptomic analysis. We confirm the upregulation of the TGFβ pathway member SMAD3 at the transcriptional and translational levels in dasatinib-resistant pre-BCR+/E2A-PBX1+ ALL cells. Hence, dasatinib blocks, at least partially, TGFβ-induced SMAD3 phosphorylation in several B-cell precursor (BCP) ALL cell lines as well as in dasatinib-resistant pre-BCR+/E2A-PBX1+ ALL cells. Activation of the TGFβ signaling pathway by TGF-β1 leads to growth inhibition by cell cycle arrest at the G0/G1 stage, increase in apoptosis and transcriptional changes of SMAD-targeted genes, e.g. c-MYC downregulation, in pre-BCR+/E2A-PBX1+ ALL cells. These results provide a better understanding about the role that the TGFβ signaling pathway plays in leukemogenesis of BCP-ALL as well as in secondary drug resistance to dasatinib.

PEG-asparaginase treatment regimens for acute lymphoblastic leukaemia in children: a network meta-analysis

BACKGROUND

Asparaginase has played a crucial role in the improvement of survival in children with acute lymphoblastic leukaemia (ALL), which is the commonest cancer among children. Survival rates have steadily increased over decades since the introduction of asparaginase to ALL therapy, and overall survival rates reach 90% with the best contemporary protocols. Currently, polyethylene glycolated native Escherichia coli-derived L-asparaginase (PEG-asparaginase) is the preferred first-line asparaginase preparation. Besides its clinical benefits, PEG-asparaginase is well known for severe toxicities. Agreement on the optimal dose, treatment duration, and frequency of administration has never been reached among clinicians.

OBJECTIVES

Primary objective To assess the effect of the number of PEG-asparaginase doses on survival and relapse in children and adolescents with ALL. Secondary objectives To assess the association between the number of doses of PEG-asparaginase and asparaginase-associated toxicities (e.g. hypersensitivity, thromboembolism, pancreatitis and osteonecrosis). To undertake a network meta-analysis at dose-level in order to generate rankings of the number of doses of PEG-asparaginase used in the treatment for ALL, according to their benefits (survival and relapse) and harms (toxicity).

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, Web of Science databases and three trials registers in November 2021, together with reference checking, citation searching and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different PEG-asparaginase treatment regimens in children and adolescents (< 18 years of age) with first-line ALL treated with multiagent chemotherapy including PEG-asparaginase.

DATA COLLECTION AND ANALYSIS

Using a standardised data collection form, two review authors independently screened and selected studies, extracted data, assessed risk of bias for each outcome using a standardised tool (RoB 2.0) and assessed the certainty of evidence for each outcome using the GRADE approach. Primary outcomes included overall survival, event-free survival and leukaemic relapse. Secondary outcomes included asparaginase-associated toxicities (hypersensitivity, thromboembolism, pancreatitis, sinusoidal obstruction syndrome and osteonecrosis as well as overall asparaginase-associated toxicity). We conducted the review and performed the analyses in accordance with the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included three RCTs in the review, and identified an additional four ongoing studies. We judged outcomes of two RCTs to be at low risk of bias in all the Cochrane risk of bias (RoB 2) domains. We rated the remaining study as having some concerns regarding bias. Due to concerns about imprecision, we rated all outcomes as having low- to moderate-certainty evidence.  One study compared intermittent PEG-asparaginase treatment (eight doses of PEG-asparaginase, 1000 IU/m2, intramuscular (IM) administration) versus continuous PEG-asparaginase treatment (15 doses of PEG-asparaginase, 1000 IU/m2, IM) in 625 participants with non-high risk ALL aged 1.0 to 17.9 years. We found that treatment with eight doses probably results in little to no difference in event-free survival compared to treatment with 15 doses (RR 1.01, 95% CI 0.97 to 1.06; moderate-certainty evidence). Compared to treatment with 15 doses, treatment with eight doses may result in either no difference or a slight reduction in hypersensitivity (RR 0.64, 95% CI 0.21 to 1.93; low-certainty evidence), thromboembolism (RR 0.55, 95% CI 0.22 to 1.36; low-certainty evidence) or osteonecrosis (RR 0.68, 95% CI 0.35 to 1.32; low-certainty evidence). Furthermore, we found that treatment with eight doses probably reduces pancreatitis (RR 0.31, 95% CI 0.12 to 0.75; moderate-certainty evidence) and asparaginase-associated toxicity (RR 0.53, 95% CI 0.35 to 0.78; moderate-certainty evidence) compared to treatment with 15 doses. One study compared low-risk standard treatment with additional PEG-asparaginase (six doses, 2500 IU/m2, IM) versus low-risk standard treatment (two doses, 2500 IU/m2, IM) in 1857 participants aged one to nine years old with standard low-risk ALL. We found that, compared to treatment with two doses, treatment with six doses probably results in little to no difference in overall survival (RR 0.99, 95% CI 0.98 to 1.00; moderate-certainty evidence) and event-free survival (RR 1.01, 95% CI 0.99 to 1.04; moderate-certainty evidence), and may result in either no difference or a slight increase in osteonecrosis (RR 1.65, 95% CI 0.91 to 3.00; low-certainty evidence). Furthermore, we found that treatment with six doses probably increases hypersensitivity (RR 12.05, 95% CI 5.27 to 27.58; moderate-certainty evidence), pancreatitis (RR 4.84, 95% CI 2.15 to 10.85; moderate-certainty evidence) and asparaginase-associated toxicity (RR 4.49, 95% CI 3.05 to 6.59; moderate-certainty evidence) compared to treatment with two doses. One trial compared calaspargase (11 doses, 2500 IU/m2, intravenous (IV)) versus PEG-asparaginase (16 doses, 2500 IU/m2, IV) in 239 participants aged one to 21 years with standard- and high-risk ALL and lymphoblastic lymphoma. We found that treatment with 11 doses of calaspargase probably results in little to no difference in event-free survival compared to treatment with 16 doses of PEG-asparaginase (RR 1.06, 95% CI 0.97 to 1.16; moderate-certainty evidence). However, treatment with 11 doses of calaspargase probably reduces leukaemic relapse compared to treatment with 16 doses of PEG-asparaginase (RR 0.32, 95% CI 0.12 to 0.83; moderate-certainty evidence). Furthermore, we found that treatment with 11 doses of calaspargase results in either no difference or a slight reduction in hypersensitivity (RR 1.17, 95% CI 0.64 to 2.13; low-certainty evidence), pancreatitis (RR 0.85, 95% CI 0.47 to 1.52; low-certainty evidence), thromboembolism (RR 0.83, 95% CI 0.48 to 1.42; low-certainty evidence), osteonecrosis (RR 0.63, 95% CI 0.15 to 2.56; low-certainty evidence) and asparaginase-associated toxicity (RR 1.00, 95% CI 0.71 to 1.40; low-certainty evidence) compared to treatment with 16 doses of PEG-asparaginase.

AUTHORS' CONCLUSIONS

We were not able to conduct a network meta-analysis, and could not draw clear conclusions because it was not possible to rank the interventions. Overall, we found that different numbers of doses of PEG-asparaginase probably result in little to no difference in event-free survival across all studies. In two studies, we found that a higher number of PEG-asparaginase doses probably increases pancreatitis and asparaginase-associated toxicities.

Invasive fungal diseases impact on outcome of childhood ALL - an analysis of the international trial AIEOP-BFM ALL 2009

In children with acute lymphoblastic leukemia (ALL), risk groups for invasive fungal disease (IFD) with need for antifungal prophylaxis are not well characterized, and with the advent of new antifungal compounds, current data on outcome are scarce. Prospectively captured serious adverse event reports of children enrolled in the international, multi-center clinical trial AIEOP-BFM ALL2009 were screened for proven/probable IFD, defined according to the updated EORTC/MSG consensus definitions. In a total of 6136 children (median age 5.2 years), 224 proven/probable IFDs (65 yeast and 159 mold) were reported. By logistic regression, the risk for proven/probable IFDs was significantly increased in children ≥12 years and those with a blast count ≥10% in the bone marrow on day 15 (P < 0.0001 each). Proven/probable IFDs had a 6-week and 12-week mortality of 10.7% and 11.2%, respectively. In the multivariate analysis, the hazard ratio for event-free and overall survival was significantly increased for proven/probable IFD, age ≥12 years, and insufficient response to therapy (P < 0.001, each). Our data define older children with ALL and those with insufficient treatment-response at high risk for IFD. As we show that IFD is an independent risk factor for event-free and overall survival, these patients may benefit from targeted antifungal prophylaxis.

Peripheral Bone Relapse of Paediatric TCF3-HLF Positive Acute Lymphoblastic Leukaemia during Haematopoietic Stem Cell Transplantation: A Case Report

The present case report features a highly uncommon form of a paediatric TCF3-HLF positive acute lymphoblastic leukaemia (ALL) relapse, an extramedullary, peripheral bone manifestation. Following complete remission, during the conditioning for haematopoietic stem cell transplantation (HSCT), our sixteen-year-old male patient complained of fever, pain and swelling of the right forearm. Radiography suggested acute osteomyelitis in the right ulna with subsequent surgical confirmation. Intraoperatively obtained debris culture grew Staphylococcus aureus and Acinetobacter pittii. Measures taken to control the infection were deemed to be successful. However, after the completion of the otherwise uneventful HSCT, a very early medullary relapse was diagnosed. Revising the original surgical samples from the ulna, bone relapse of ALL was immunohistochemically confirmed. Reviewing the previous cases found in the literature, it is advised to consider uncommon forms of ALL relapse when encountering ambiguous cases of osteomyelitis or arthritis during haematological remission.

Parametric Models for Survival Analysis of Childhood Cancer Patients' Data

Background: The rate of childhood cancer death has dropped steadily over the past 50 years. The pediatric cancer risk has remained under investigation. Objectives: This study aims at investigating the associated factors with the survival of pediatric patients with retinoblastoma, sarcoma, brain tumor, and leukemia cancer. Methods: The cohort study of 1879 children with retinoblastoma, sarcoma, brain tumor, and leukemia aged < 1, 1 - 5, 6 - 10, 11 - 15, and > 15 years in Mahak Hospital and Rehabilitation Complex from 2007 to 2016 were enrolled in the study. Median survival time was reported for each cancer. Parametric survival models including Gompertz, Weibull, lognormal, and log‑logistic models were fitted. Then, the model with almost minimum Akaike information criterion (AIC) was chosen. The hazard ratio (HR) and the analysis were performed by R3.5.1. Results: Totally, 270 (14.37%) patients with Retinoblastoma, 667 (35.5%) with leukemia, 625 (33.26%) with a Brain tumor, and 317 (16.87%) with Sarcoma were included in this study; 815 (43.37%) patients were female. Gompertz's model was chosen to fit the data due to the minimum AIC. The associated factors with the survival of childhood cancers were as follows: age < 1 year, parental relation, loco-regional relapse and chemotherapy alone (HR: 7.63, 1.56, 4.61, 1.12) in leukemia, other nationalities, metastasis or metastasis and loco-regional relapse and chemotherapy alone (HR = 3.74, 5.75, 2.12) in retinoblastoma, loco-regional relapse and metastasis (HR = 2.40, 3.71) in brain tumor, other ages except for 5 - 10 years, parental relation, chemotherapy alone, and metastasis (HR = 33.3, 1.80, 3.57, 3.8) in sarcoma. Conclusions: Age, parental familial relationships, combination therapy, and metastasis of primary cancer were the risk factors for survival of children with 4 common cancers of leukemia, retinoblastoma, brain tumors, and sarcoma, using the Gompertz model.

Near-tetraploid T-cell acute lymphoblastic leukaemia in childhood: Results of the AIEOP-BFM ALL studies

BACKGROUND

Near-tetraploidy-defined by DNA index 1.79-2.28 or 81-103 chromosomes-is a rare cytogenetic abnormality observed both in children and adults with T-cell acute lymphoblastic leukaemia (T-ALL) and its prognostic value is not yet determined.

PATIENTS AND METHODS

We report a retrospective study conducted in paediatric patients with newly diagnosed T-ALL treated in AIEOP-BFM ALL 2000 and 2009 studies. 31 near-tetraploid T-ALL patients (1.4%) are compared to T-ALL patients without near-tetraploidy.

RESULTS

Near-tetraploid karyotype was associated with lower frequency of high-risk features: white blood cells count at diagnosis ≥100,000/μL (19.3% versus 41.0%, p-value < 0.001), PPR (13.3% versus 35.8%, p-value = 0.01) and minimal residual disease high-risk at the end of consolidation phase Induction B (4.03% versus 14.6%, p-value = 0.001). Complete remission was achieved at the end of induction phase (day 33) in 100% near-tetraploid T-ALL patients, compared to 93.2% T-ALL without near-tetraploidy.

CONCLUSION

Overall, we found that near-tetraploid T-ALL in newly diagnosed paediatric patients is associated with low-risk presenting features, with favourable treatment response and outcome.

Longer Time Intervals From Symptom Onset to Diagnosis Affect the Overall Survival in Children With Acute Lymphoblastic Leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Early diagnosis and timely treatment are essential for effective cancer control and have been widely analyzed in childhood cancer. However, few studies have described the time to diagnosis and treatment in children with ALL. This study investigated delays in diagnosis and treatment initiation and their impact on survival.

METHODS

This retrospective cohort study included 419 patients 0 to 14 years old at a tertiary hospital between 2011 and 2015. The optimal cutoff values for delays were determined by X-tile software. The Kaplan-Meier method and Cox regression models were used to evaluate the impact of delays on survival.

RESULTS

The median diagnosis, treatment, and total delays were 21 (interquartile range [IQR]: 11-35), 4 (IQR: 2-7), and 26 (IQR: 16-43) days, respectively. The results of multivariate analyses showed that diagnosis delay, risk stratification, and minimal residual disease level were independent predictors for treatment outcome in childhood ALL.

CONCLUSIONS

These findings suggested that a longer time to diagnosis negatively affected the clinical outcome of childhood ALL. Reducing the time to diagnosis could help to improve survival in these patients.

S100A8 inhibition in leukemic lymphoblasts induces sensitivity to chemotherapy and inhibition of disease relapse

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and relapsed B-ALL is the leading cause of mortality in children with leukemia due to a lack of response to treatment. S100A8 is a low molecular weight calcium-binding intracellular protein that is expressed in certain cells, and its increased expression is seen in most tumors as well as in relapsed childhood B-ALL cases. The present study indicates the important role of S100A8 in improving viability and resistance to chemotherapy in relapsed B-ALL lymphoblasts. S100A8 levels were compared in B-ALL and relapsed B-ALL lymphoblasts that were sensitive and resistant to Vincristine, respectively. S100A8 was inhibited in the lymphoblasts of two patients by antisense locked nucleic acid (LNA) GapmeRs and the decreased expression of S100A8 was evaluated using quantitative real-time PCR and ELISA. Then, the S100A8 antisense LNA GapmeRs-transfected cells were treated with Vincristine and the expression levels of S100A8 mRNA and S100A8 protein were re-determined. At all of these stages, cell viability and LC50 were assessed by MTT assay. The results showed that S100A8 levels in relapsed B-ALL lymphoblasts were significantly higher than B-ALL lymphoblasts. Moreover, the increase in S100A8 expression was proportionate to the increase in Vincristine resistance in these cells. The S100A8 knockdown procedure using antisense LNA GapmeRs decreased the cell viability and increased vincristine sensitivity in lymphoblasts of two patients, and it also increased the sensitivity to chemotherapy in relapsed B-ALL lymphoblasts. According to the findings of the present study, S100A8 is effective in developing lymphoblast resistance to chemotherapy, and its enhanced expression may contribute to shifting B-ALL into the relapse phase of the illness. As a result, S100A8 may be a valuable target for managing and improving relapses B-ALL.

The Promise of Single-cell Technology in Providing New Insights Into the Molecular Heterogeneity and Management of Acute Lymphoblastic Leukemia

Drug resistance and treatment failure in pediatric acute lymphoblastic leukemia (ALL) are in part driven by tumor heterogeneity and clonal evolution. Although bulk tumor genomic analyses have provided some insight into these processes, single-cell sequencing has emerged as a powerful technique to profile individual cells in unprecedented detail. Since the introduction of single-cell RNA sequencing, we now have the capability to capture not only transcriptomic, but also genomic, epigenetic, and proteomic variation between single cells separately and in combination. This rapidly evolving field has the potential to transform our understanding of the fundamental biology of pediatric ALL and guide the management of ALL patients to improve their clinical outcome. Here, we discuss the impact single-cell sequencing has had on our understanding of tumor heterogeneity and clonal evolution in ALL and provide examples of how single-cell technology can be integrated into the clinic to inform treatment decisions for children with high-risk disease.

Prospective quantitative gene expression analysis of kallikrein-related peptidase KLK10 as a diagnostic biomarker for childhood acute lymphoblastic leukemia

Background

The most common malignancy in children is acute lymphoblastic leukemia (ALL). This study aimed to explore KLK10 mRNA expression as a potential diagnostic biomarker for ALL in children and to examine the effect of chemotherapy on KLK10 mRNA expression following the induction and after three months of receiving chemotherapy.

Methods

In this prospective study, total RNA was extracted from blood samples of 23 pediatric ALL patients on diagnosis, after one month and three months of receiving chemotherapy. Healthy pediatric volunteers (n = 12) were selected as control individuals. After cDNA synthesis, KLK10 mRNA gene expression levels were quantified using quantitative real-time PCR (qRT-PCR).

Results

KLK10 mRNA expression levels were significantly decreased in leukemic cells compared to their levels in cells of normal blood samples (p = 0.0001). KLK10 expression levels in ALL patients after one month and three months of receiving chemotherapy decreased compared to normal blood samples (p < 0.0001 and p = 0.0175 respectively). The expression level of KLK10 mRNA in ALL patients after one month of chemotherapy was decreased compared to their level on diagnosis (p = 0.4413). KLK10 mRNA expression levels in ALL patients after three months of chemotherapy were increased compared to their level on diagnosis (p = 0.0602). The ROC curve illustrated that KLK10 mRNA expression could very efficiently discriminate ALL patients from normal counterparts (AUC=0.886, 95% CI [0.7720-1.000], SE = 0.0582, p = 0.0004).

Conclusion

KLK10 mRNA expression could serve as a potential diagnostic molecular biomarker for ALL in children.

Children's Oncology Group Trial AALL1231: A Phase III Clinical Trial Testing Bortezomib in Newly Diagnosed T-Cell Acute Lymphoblastic Leukemia and Lymphoma

PURPOSE

To improve the outcomes of patients with T-cell acute lymphoblastic leukemia (T-ALL) and lymphoblastic lymphoma (T-LL), the proteasome inhibitor bortezomib was examined in the Children's Oncology Group phase III clinical trial AALL1231, which also attempted to reduce the use of prophylactic cranial radiation (CRT) in newly diagnosed T-ALL.

PATIENTS AND METHODS

Children and young adults with T-ALL/T-LL were randomly assigned to a modified augmented Berlin-Frankfurt-Münster chemotherapy regimen with/without bortezomib during induction and delayed intensification. Multiple modifications were made to the augmented Berlin-Frankfurt-Münster backbone used in the predecessor trial, AALL0434, including using dexamethasone instead of prednisone and adding two extra doses of pegaspargase in an attempt to eliminate CRT in most patients.

RESULTS

AALL1231 accrued 824 eligible and evaluable patients from 2014 to 2017. The 4-year event-free survival (EFS) and overall survival (OS) for arm A (no bortezomib) versus arm B (bortezomib) were 80.1% ± 2.3% versus 83.8% ± 2.1% (EFS, P = .131) and 85.7% ± 2.0% versus 88.3% ± 1.8% (OS, P = .085). Patients with T-LL had improved EFS and OS with bortezomib: 4-year EFS (76.5% ± 5.1% v 86.4% ± 4.0%; P = .041); and 4-year OS (78.3% ± 4.9% v 89.5% ± 3.6%; P = .009). No excess toxicity was seen with bortezomib. In AALL0434, 90.8% of patients with T-ALL received CRT. In AALL1231, 9.5% of patients were scheduled to receive CRT. Evaluation of comparable AALL0434 patients who received CRT and AALL1231 patients who did not receive CRT demonstrated no statistical differences in EFS (P = .412) and OS (P = .600).

CONCLUSION

Patients with T-LL had significantly improved EFS and OS with bortezomib on the AALL1231 backbone. Systemic therapy intensification allowed elimination of CRT in more than 90% of patients with T-ALL without excess relapse.

Identification of a novel GOLGA4-JAK2 fusion gene in B-cell acute lymphoblastic leukaemia

Rearrangements of Janus kinase 2 (JAK2r) form a subtype of acute lymphoblastic leukaemia (ALL) associated with poor patient outcomes. We present a high-risk case of B-cell ALL (B-ALL) where retrospective mRNA sequencing identified a novel GOLGA4-JAK2 fusion gene. Expression of GOLGA4-JAK2 in murine pro-B cells promoted factor-independent growth, implicating GOLGA4-JAK2 as an oncogenic driver. Cells expressing GOLGA4-JAK2 demonstrated constitutive activation of JAK/STAT signalling and were sensitive to JAK inhibitors. This study contributes to the diverse collection of JAK2 fusion genes identified in B-ALL and supports the incorporation of JAK inhibitors into treatment strategies to improve outcomes for this subtype.

GSTM1 and GSTT1 double null genotypes determining cell fate and proliferation as potential risk factors of relapse in children with hematological malignancies after hematopoietic stem cell transplantation

PURPOSE

This study aimed to retrospectively evaluate the genetic association of null variants of glutathione S-transferases GSTM1 and GSTT1 with relapse incidence in children with hematological malignancies (HMs) undergoing busulfan (BU)- containing allogeneic hematopoietic stem cell transplantation (HSCT) and to assess the impact of these variants on BU-induced cytotoxicity on the immortalized lymphoblastoid cell lines (LCLs) and tumor THP1 GST gene-edited cell models.

METHODS

GSTM1- and GSTT1-null alleles were genotyped using germline DNA from whole blood prior to a conditioning BU-based regimen. Association of GSTM1- and GSTT1-null variants with relapse incidence was analyzed using multivariable competing risk analysis. BU-induced cell death studies were conducted in GSTs- null and non-null LCLs and CRISPR-Cas9 gene-edited THP1 leukemia cell lines.

RESULTS

Carrying GSTM1/GSTT1 double null genotype was found to be an independent risk factor for post-HSCT relapse in 86 children (adjusted HR: 6.52 [95% Cl, 2.76-15.42; p = 1.9 × 10^-5]). BU-induced cell death preferentially in THP1^{GSTM1(non-null)} and LCLs^{GSTM1(non-null)} as shown by decreased viability, increased necrosis and levels of the oxidized form of glutathione compared to null cells, while GSTT1 non-null cells showed increased baseline proliferation.

CONCLUSION

The clinical association suggests that GSTM1/GSTT1 double null genotype could serve as genetic stratification biomarker for the high risk of post-HSCT relapse. Functional studies have indicated that GSTM1 status modulates BU-induced cell death. On the other hand, GSTT1 is proposed to be involved in baseline cell proliferation.

Clinical features and prognostic impact of TCF3-PBX1 in childhood acute lymphoblastic leukemia: A single-center retrospective study of 837 patients from China

OBJECTIVES

Conflicting data have been published regarding the prognostic impact of the t(1;19)/TCF3-PBX1 translocation in childhood ALL. The objective of this study was to explore the correlation between the TCF3-PBX1 fusion gene and clinical outcome in Chinese children with newly diagnosed ALL.

METHODS

In order to address this issue in our setting, we summarized and analyzed the data of 837 Chinese children with ALL diagnosed between 2010 and 2017. All the patients were treated with the National Protocol of Childhood Leukemia in China (NPCLC)-ALL-2008 protocol. Clinical characteristics and prognosis of pediatric ALL patients with or without TCF3-PBX1 rearrangement were analyzed and compared retrospectively.

RESULTS

The TCF3-PBX1 fusion gene was identified in 48 (5.7%) of 837 children with ALL. Our results showed that TCF3-PBX1 positive patients had higher pretreatment white blood cell counts, higher PB blasts percentages and worse risk classification at diagnosis. No statistically significant differences in CR rates, response to prednisone and relapse rates were found between TCF3-PBX1-positive and -negative patients. The 5-year predicted EFS, RFS, and OS of the TCF3-PBX1 positive group compared with the control group were 86.2%±5.3% vs 85.4%±1.3% (P=0.657), 88.2%±5.1% vs 92.2%±1.0% (P=0.458) and 90.4%±4.6% vs 89.0%±1.1% (P=0.561), respectively. No differences were observed regarding clinical outcome between these two groups. When compared with standard risk, intermediate risk and high risk group patients, the long-term survival of TCF3/PBX1 positive group was approximately similar to that of the intermediate risk group under the same protocol in our single center.

CONCLUSION

In contrast to previous studies, childhood ALL patients with TCF3-PBX1 transcripts do not appear to show a better outcome than their negative counterparts. TCF3/PBX1 positive was a definitive intermediate risk factor with our NPCLC-ALL-2008 protocol.

Forecasting essential childhood cancer drug need: An innovative model-based approach

BACKGROUND

Childhood cancer outcomes in low-income and middle-income countries have not kept pace with advances in care and survival in high-income countries. A contributing factor to this survival gap is unreliable access to essential drugs.

METHODS

The authors created a tool (FOR_x ECAST) capable of predicting drug quantity and cost for 18 pediatric cancers. FOR_x ECAST enables users to estimate the quantity and cost of each drug based on local incidence, stage breakdown, treatment regimen, and price. Two country-specific examples are used to illustrate the capabilities of FOR_x ECAST to predict drug quantities.

RESULTS

On the basis of domestic public-sector price data, the projected annual cost of drugs to treat childhood cancer cases is 0.8 million US dollars in Kenya and 3.0 million US dollars in China, with average median price ratios of 0.9 and 0.1, respectively, compared with costs sourced from the Management Sciences for Health (MSH) International Medical Products Price Guide. According to the cumulative chemotherapy cost, the most expensive disease to treat is acute lymphoblastic lymphoma in Kenya, but a higher relative unit cost of methotrexate makes osteosarcoma the most expensive diagnosis to treat in China.

CONCLUSIONS

FOR_x ECAST enables needs-based estimates of childhood cancer drug volumes to inform health system planning in a wide range of contexts. It is broadly adaptable, allowing decision makers to generate results specific to their needs. The resultant estimates of drug need can help equip policymakers and health governance institutions with evidence-informed data to advance innovative procurement strategies that drive global improvements in childhood cancer drug access.

Combinatorial efficacy of entospletinib and chemotherapy in patient-derived xenograft models of infant acute lymphoblastic leukemia

Survival of infants with KMT2A-rearranged acute lymphoblastic leukemia (ALL) remains dismal despite intensive chemotherapy. We observed constitutive phosphorylation of spleen tyrosine kinase (SYK) and associated signaling proteins in infant ALL patient-derived xenograft (PDX) model specimens and hypothesized that the SYK inhibitor entospletinib would inhibit signaling and cell growth in vitro and leukemia proliferation in vivo. We further predicted that combined entospletinib and chemotherapy could augment anti-leukemia effects. Basal kinase signaling activation and HOXA9/MEIS1 expression differed among KMT2Arearranged (KMT2A-AFF1 [n=4], KMT2A-MLLT3 [n=1], KMT2A-MLLT1 [n=4]) and non-KMT2A-rearranged [n=3] ALL specimens and stratified by genetic subgroup. Incubation of KMT2A-rearranged ALL cells in vitro with entospletinib inhibited methylcellulose colony formation and SYK pathway signaling in a dose-dependent manner. In vivo inhibition of leukemia proliferation with entospletinib monotherapy was observed in RAS-wild-type KMT2A-AFF1, KMT2A-MLLT3, and KMT2A-MLLT1 ALL PDX models with enhanced activity in combination with vincristine chemotherapy in several models. Surprisingly, entospletinib did not decrease leukemia burden in two KMT2A-AFF1 PDX models with NRAS or KRAS mutations, suggesting potential RAS-mediated resistance to SYK inhibition. As hypothesized, superior inhibition of ALL proliferation was observed in KMT2A-AFF1 PDX models treated with entospletinib and the MEK inhibitor selumetinib versus vehicle or inhibitor monotherapies (P<0.05). In summary, constitutive activation of SYK and associated signaling occurs in KMT2A-rearranged ALL with in vitro and in vivo sensitivity to entospletinib. Combination therapy with vincristine or selumetinib further enhanced treatment effects of SYK inhibition. Clinical study of entospletinib and chemotherapy or other kinase inhibitors in patients with KMT2A-rearranged leukemias may be warranted.

Patient with Down syndrome and relapsed acute lymphoblastic leukemia with sustained remission despite only partial R3 chemotherapy

DS-ALL has a higher rate of relapse and treatment-related mortality. The newer immunotherapies are potentially better options. Relapsed ALL with positive MRD has a poor prognosis. Transient long-term remission after ALL relapse due to partial chemotherapy combined severe infection is rare.

Chemotherapy Delays Are Associated with Inferior Outcome in Acute Lymphoblastic Leukemia: A Retrospective Study from a Tertiary Cancer Center in South India

Background Treatment protocols for acute lymphoblastic leukemia (ALL) have evolved over time to give excellent cure rates in children and moderate outcomes in adults; however, little is known how delays in chemotherapy affect long-term survival.

Objectives To find the association of delays during different treatment phases on the survival outcomes.

Materials and Methods Data from 149 ALL cases treated between 2009 and 2015 were retrospectively analyzed. Treatment course in commonly used protocols was divided into three phases—induction, consolidation (postremission), maintenance, and also a combined intensive phase (induction plus consolidation) for the purpose of analysis, and delay in each phase was defined based on clinically acceptable breaks. Analysis was done to find the impact of treatment delay in each phase on the survival outcomes.

Results The median age was 12 years (range, 1–57). Multi-center Protocol-841 (MCP-841) was used for 72%, German Multicenter Study Group for Adult ALL (GMALL) for 19%, and Berlin, Frankfurt, Muenster, 95 protocol (BFM-95) for 9% of patients. Delay in induction was seen in 52%, consolidation in 66%, and during maintenance in 42% of patients. The median follow-up was 41 months, and 3-year survival outcomes for the entire cohort were event-free survival (EFS)—60%, relapse-free survival (RFS)—72%, and overall survival (OS)—68%. On univariate analysis, delay in induction adversely affected EFS (hazard ratio [HR] = 1.78, p = 0.04), while delay in intensive phase had significantly worse EFS and RFS (HR = 2.41 [p = 0.03] and HR = 2.57 [p = 0.03], respectively). On separate analysis of MCP-841 cohort, delay in intensive phase affected both EFS (HR = 3.85, p = 0.02) and RFS (HR = 3.42, p = 0.04), whereas delay in consolidation significantly affected OS with (HR = 4.74, p = 0.04) independently.

Conclusion Treatment delays mostly in intensive phase are associated with worse survival in ALL; attempts should be made to maintain protocol-defined treatment intensity while adequately managing toxicities.

Role of Pirin, an Oxidative Stress Sensor Protein, in Epithelial Carcinogenesis

Pirin is an oxidative stress (OS) sensor belonging to the functionally diverse cupin superfamily of proteins. Pirin is a suggested quercetinase and transcriptional activator of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Its biological role in cancer development remains a novel area of study. This review presents accumulating evidence on the contribution of Pirin in epithelial cancers, involved signaling pathways, and as a suggested therapeutic target. Finally, we propose a model in which Pirin is upregulated by physical, chemical or biological factors involved in OS and cancer development.

Clinical features and outcome of pediatric acute lymphoblastic leukemia with low peripheral blood blast cell count at diagnosis

Peripheral blood (PB) blast cell count on day 8 of prednisone therapy has been considered one of the strongest predictors of outcome in children with acute lymphoblastic leukemia (ALL). However, little is known about the clinical features and prognostic impact of PB blast cell count at diagnosis in these patients. The aim of this study was to evaluate the relationship between initial PB blast cell count and clinical prognosis of pediatric ALL.The study comprised 367 patients with ALL, aged 0 to 14 years, enrolled and treated using the Chinese Children's Leukemia Group-ALL 2008 protocol between 2011 and 2015. The majority (91.6%) of patients were B-cell precursor ALL (BCP ALL), and 8.4% were T-cell ALL (T-ALL).Patients with BCP ALL in the low PB blast cell count group (<1 × 109/L) had significantly superior survival rates to those in the high count group (≥30 × 109/L). In T-ALL, the low count group showed significantly inferior survival rates compared to both the intermediate count group (1-29.9 × 109/L) and high count group. Multivariate analysis revealed that the initial white blood cell count and minimal residual disease at the end of induction therapy were independently predictive of BCP ALL outcome, while risk stratification was shown to be an independent prognostic factor for T-ALL outcome.These results indicated that low blast cell count in PB at diagnosis was associated with different clinical outcomes in patients with BCP ALL and T-ALL, although it was not an independent outcome predictor by multivariate analysis.

Acute Complications and Survival Analysis of Childhood Acute Lymphoblastic Leukemia: A 15-year Experience

BACKGROUND

We evaluated the acute complications that occurred during the treatment of childhood acute lymphoblastic leukemia (ALL) and documented the survival rates of children with ALL.

MATERIALS AND METHODS

We retrospectively evaluated 110 children with a diagnosis of ALL treated with the Children's Oncology Group protocol from 1999 to 2014. The demographic, clinical, and laboratory data of 110 patients and acute complications of eligible and evaluable 105 patients were recorded.

RESULTS

Of the 110 patients, 65 were male and 45 were female. The mean age at admission was 8.3 ± 5.2 years. Ninety-seven patients (88.2%) had been diagnosed with pre-B-cell ALL, 11 (10%) with T-cell ALL, 1 (0.9%) with mixed phenotype acute leukemia, and 1 (0.9%) with mature B-cell acute leukemia. Of the 110 patients, 40 (36.3%) were in the standard-risk group and 70 (63.7%) were in high-risk group. Of the 110 patients, 105 had been followed up regularly and evaluated for acute complications. Infection was the most common complication (n = 93; 88.5%), followed by gastrointestinal (n = 29; 27.6%), neurologic (n = 28; 26.6%), metabolic/endocrine (n = 16; 15.2%), drug-related hypersensitivity (n = 16; 15.2%), avascular necrosis (n = 13; 12.3%), thrombotic (n = 11; 10.4%), severe psychiatric (n = 2; 1.9%), and various other (n = 12; 11.4%) complications. Of the 110 patients, 98 were assessed in terms of survival analysis. The 5- and 10-year overall survival rates were both 85.9% (standard error [SE], 3.6%). The relapse-free survival rates at 1, 3, and 5 years were 97.9% (SE, 1.5%), 91.3% (SE, 3%), and 86.3% (SE, 3.7%), respectively.

CONCLUSION

Childhood ALL, although categorized as curable malignancy owing to the improvements in treatment strategies in recent years, can cause acute complications affecting various systems. Thus, patients should be treated and followed up by multidisciplinary medical teams with high expertise.

Menin inhibitor MI-3454 induces remission in MLL1-rearranged and NPM1-mutated models of leukemia

The protein-protein interaction between menin and mixed lineage leukemia 1 (MLL1) plays a critical role in acute leukemias with translocations of the MLL1 gene or with mutations in the nucleophosmin 1 (NPM1) gene. As a step toward clinical translation of menin-MLL1 inhibitors, we report development of MI-3454, a highly potent and orally bioavailable inhibitor of the menin-MLL1 interaction. MI-3454 profoundly inhibited proliferation and induced differentiation in acute leukemia cells and primary patient samples with MLL1 translocations or NPM1 mutations. When applied as a single agent, MI-3454 induced complete remission or regression of leukemia in mouse models of MLL1-rearranged or NPM1-mutated leukemia, including patient-derived xenograft models, through downregulation of key genes involved in leukemogenesis. We also identified MEIS1 as a potential pharmacodynamic biomarker of treatment response with MI-3454 in leukemia, and demonstrated that this compound is well tolerated and did not impair normal hematopoiesis in mice. Overall, this study demonstrates, for the first time to our knowledge, profound activity of the menin-MLL1 inhibitor as a single agent in clinically relevant PDX models of leukemia. These data provide a strong rationale for clinical translation of MI-3454 or its analogs for leukemia patients with MLL1 rearrangements or NPM1 mutations.

Sexual Dimorphism in Children and Adolescents With Acute Lymphoblastic Leukemia: Influence on Incidence and Survival

Acute lymphoblastic leukemia (ALL) incidence and poor prognosis are higher in male individuals. There is a lack of studies assessing the influence of sex in ALL. We documented this influence in a homogenous cohort. Three hundred three ALL Hispanic patients 1 to 20 years of age diagnosed over 10 years at a university hospital were evaluated. Patients were divided by sex and stratified by age. Survival rates were assessed by the Kaplan-Meier method, and the Cox model was used for univariate and multivariate analysis. The median age for female individuals was 6 years versus 9 years for male individuals (P=0.002). In the whole cohort, there was a male preponderance (P=0.025), with a 1.3 male-to-female ratio. For male individuals, the 5-year relapse-free survival was 46%; for female individuals, it reached 58.7%, (P=0.009). Male individuals 1-9 years of age had a lower 5-year relapse-free survival than female individuals, 51.5% versus 66.7% (95% confidence interval, 65.35-68.01; P=0.020); this was not the case for overall survival (P=0.660). The male-to-female ratio in the 10 to 15 years' group was 1.59, and 2.35 in the 16 to 20 years' group. Incidence and relapse of ALL were higher in male individuals. A skewed distribution in the 10 to 20 years' age group disproportionately affected male individuals, suggesting a hormonal influence.

Role of microRNA dysregulation in childhood acute leukemias: Diagnostics, monitoring and therapeutics: A comprehensive review

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of genes by sequence-specific binding to mRNA to either promote or block its translation; they can also act as tumor suppressors (e.g., let-7b, miR-29a, miR-99, mir-100, miR-155, and miR-181) and/or oncogenes (e.g., miR-29a, miR-125b, miR-143-p3, mir-155, miR-181, miR-183, miR-196b, and miR-223) in childhood acute leukemia (AL). Differentially expressed miRNAs are important factors associated with the initiation and progression of AL. As shown in many studies, they can be used as noninvasive diagnostic and prognostic biomarkers, which are useful in monitoring early stages of AL development or during therapy (e.g., miR-125b, miR-146b, miR-181c, and miR-4786), accurate classification of different cellular or molecular AL subgroups (e.g., let-7b, miR-98, miR-100, miR-128b, and miR-223), and identification and development of new therapeutic agents (e.g., mir-10, miR-125b, miR-203, miR-210, miR-335). Specific miRNA patterns have also been described for commonly used AL therapy drugs (e.g., miR-125b and miR-223 for doxorubicin, miR-335 and miR-1208 for prednisolone, and miR-203 for imatinib), uncovering miRNAs that are associated with treatment response. In the current review, the role of miRNAs in the development, progression, and therapy monitoring of pediatric ALs will be presented and discussed.

Examining treatment responses of diagnostic marrow in murine xenografts to predict relapse in children with acute lymphoblastic leukaemia

BACKGROUND

While current chemotherapy has increased cure rates for children with acute lymphoblastic leukaemia (ALL), the largest number of relapsing patients are still stratified as medium risk (MR) at diagnosis (50-60%). This highlights an opportunity to develop improved relapse-prediction models for MR patients. We hypothesised that bone marrow from MR patients who eventually relapsed would regrow faster in a patient-derived xenograft (PDX) model after induction chemotherapy than samples from patients in long-term remission.

METHODS

Diagnostic bone marrow aspirates from 30 paediatric MR-ALL patients (19 who relapsed, 11 who experienced remission) were inoculated into immune-deficient (NSG) mice and subsequently treated with either control or an induction-type regimen of vincristine, dexamethasone, and L-asparaginase (VXL). Engraftment was monitored by enumeration of the proportion of human CD45⁺ cells (%huCD45⁺) in the murine peripheral blood, and events were defined a priori as the time to reach 1% huCD45⁺, 25% huCD45⁺ (TT25%) or clinical manifestations of leukaemia (TTL).

RESULTS

The TT25% value significantly predicted MR patient relapse. Mutational profiles of PDXs matched their tumours of origin, with a clonal shift towards relapse observed in one set of VXL-treated PDXs.

CONCLUSIONS

In conclusion, establishing PDXs at diagnosis and subsequently applying chemotherapy has the potential to improve relapse prediction in paediatric MR-ALL.

Post-induction Measurable Residual Disease Using Multicolor Flow Cytometry Is Strongly Predictive of Inferior Clinical Outcome in the Real-Life Management of Childhood T-Cell Acute Lymphoblastic Leukemia: A Study of 256 Patients

Background: Measurable/minimal residual disease (MRD) status is suggested as a powerful indicator of clinical-outcome in T-cell lymphoblastic leukemia/lymphoma (T-ALL). Contrary to B-cell ALL, reports on T-ALL MRD are limited and mostly based on molecular methods, mainly from developed countries. Multicolor flow cytometry (MFC)-based T-ALL studies are very few. Clinically relevant cut-off levels and ideal time-point for MRD assessment are still inconclusive. In view of lack of T-ALL MRD data from the developing world, we evaluated the prognostic value of MFC-based post-induction (PI)-MRD assessment in T-ALL in the context of standard practice. Methods: We included 256 childhood-T-ALL patients (age < 15 years) treated with a modified-MCP841 protocol, which uses high-dose cytarabine during consolidation, as a part of standard hospital practice. MRD was studied using 10-color 11-antibody MFC with any level of detectable disease being considered positive. Post-induction (PI)-MRD was available in all patients, and post-consolidation (PC) MRD was available mostly in PI-MRD-positive patients (n = 88). Results: Three years cumulative-incidence-of-relapse (3years-CIR) in PI-MRD-positive patients was inferior to negative patients (46.3% vs. 18.4%). The median relapse-free-survival (RFS), event-free-survival (EFS) and overall-survival (OS) with hazard ratio (HR) of PI-MRD-positive patients were 21.4 months vs not reached (p < 0.0001, HR-4.7), 21.6 months vs. not-reached (p = 0.0003, HR-2.01) and 37.3 months vs. not reached (p = 0.026, HR-1.64) respectively. RFS, EFS and OS of patients with PI-MRD<0.01% (n = 17) were as inferior as PI-MRD ≥ 0.01% in comparison with MRD-negative patients with HR of 4.7 (p < 0.0001), 2.45 (p = 0.0003), and 2.5 (p = 0.029), respectively. Three-years-CIR of patients with hyperleukocytosis (≥100 × 109/L) was also higher (50.5 vs. 27.6%) with inferior RFS, EFS, and OS. Among PI-MRD-positive patients, 3years-CIR, RFS, EFS, and OS of PC-MRD-positive were also inferior to that of negative patients. On multivariate analysis any-level detectable PI-MRD and hyperleukocytosis remained independently associated with inferior RFS, EFS, and OS. A combination of PI-MRD-positive status and hyperleukocytosis identified the patients with the worst clinical outcomes. Conclusion: Detectable PI-MRD using MFC was found to be the strong predictive factor of inferior clinical outcome in T-ALL patients. The combination of PI-MRD status and hyperleukocytosis provides the most influential tool for the management of T-ALL in resource constrained settings from developing world.

Treatment with anti CD19 chimeric antigen receptor T cells after antibody-based immunotherapy in adults with acute lymphoblastic leukemia

PURPOSE OF THE STUDY

The prognosis of patients with relapsed/refractory precursor B-acute lymphoblastic leukemia (ALL) is dismal. Antibody-based therapies, such as blinatumomab or inotuzumab ozogamycin (IO) have led to improved outcomes. The impact of prior immunotherapy on chimeric antigen receptor (CAR) T-Cell therapeutic efficacy and toxicity is unknown.

METHODS

We describe a case series of ALL patients with prior exposure to blinatumomab or IO, who were treated with anti-CD19 CAR T cells with CD28 co-stimulatory domain (NCT02772198). We then review the literature on CAR-T post antibody-based therapy with either antibodies.

RESULTS

Five adult patients with B-ALL were included. Three had active disease, and two were in morphological complete remission (CR) with minimal residual disease (MRD+). Therapy before CAR-T included blinatumomab (3/5 [60 %]) and IO (3/5 [60 %]), with one patient receiving both. One patient experienced severe cytokine release syndrome and central nervous system toxicity and subsequently died. At 28 days following treatment, two patients achieved CR with MRD negativity, and two had an MRD + CR. Two patients received allogeneic hematopoietic stem cell transplantation. At a median of 10 months (range, 5-26, three out of the four patients are still in CR, and one relapsed. The literature review identified a deficiency on data on the influence of blinatumumab and IO on outcomes post CAR-T therapy.

CONCLUSIONS

CD19 CAR T-cell therapy after treatment with blinatumomab and/or IO in patients with relapsed/refractory B-ALL is feasible and results in promising response rates in this case series. Future trails should specifically address outcomes in this population.

Outcome in Children With Standard-Risk B-Cell Acute Lymphoblastic Leukemia: Results of Children's Oncology Group Trial AALL0331

PURPOSE

Children's Oncology Group (COG) AALL0331 tested whether intensified postinduction therapy that improves survival in children with high-risk B-cell acute lymphoblastic leukemia (ALL) would also improve outcomes for those with standard-risk (SR) ALL.

PATIENTS AND METHODS

AALL0331 enrolled 5,377 patients between 2005 and 2010. All patients received a 3-drug induction with dexamethasone, vincristine, and pegaspargase (PEG) and were then classified as SR low, SR average, or SR high. Patients with SR-average disease were randomly assigned to receive either standard 4-week consolidation (SC) or 8-week intensified augmented Berlin-Frankfurt-Münster (BFM) consolidation (IC). Those with SR-high disease were nonrandomly assigned to the full COG-augmented BFM regimen, including 2 interim maintenance and delayed intensification phases.

RESULTS

The 6-year event-free survival (EFS) rate for all patients enrolled in AALL0331 was 88.96% ± 0.46%, and overall survival (OS) was 95.54% ± 0.31%. For patients with SR-average disease, the 6-year continuous complete remission (CCR) and OS rates for SC versus IC were 87.8% ± 1.3% versus 89.1% ± 1.2% (P = .52) and 95.8% ± 0.8% versus 95.2% ± 0.8% (P = 1.0), respectively. Those with SR-average disease with end-induction minimal residual disease (MRD) of 0.01% to < 0.1% had an inferior outcome compared with those with lower MRD and no improvement with IC (6-year CCR: SC, 77.5% ± 4.8%; IC, 77.1% ± 4.8%; P = .71). At 6 years, the CCR and OS rates among 635 nonrandomly treated patients with SR-high disease were 85.55% ± 1.49% and 92.97% ± 1.08%, respectively.

CONCLUSION

The 6-year OS rate for > 5,000 children with SR ALL enrolled in AALL0331 exceeded 95%. The addition of IC to treatment for patients with SR-average disease did not improve CCR or OS, even in patients with higher MRD, in whom it might have been predicted to provide more value. The EFS and OS rates are excellent for this group of patients with SR ALL, with particularly good outcomes for those with SR-high disease.

Secondhand smoke: A new and modifiable prognostic factor in childhood acute lymphoblastic leukemias

BACKGROUND

The 5-year overall survival (OS) in childhood acute lymphoblastic leukemia (ALL) has reached 90% in high-income countries, levels that can no be longer overcome with strategies based on intensification of treatment. Other approaches in the search for new and modifiable prognostic factors are necessary to continue to improve these rates. The importance of environmental factors in the etiopathogenesis of childhood ALL has been regaining interest but its role in the prognosis and survival of this disease is not well explored. We aim to investigate the association between secondhand smoke (SHS) and survival in children diagnosed with ALL.

METHODS

We analyzed survival rates in 146 patients under the age of 15 years diagnosed with ALL between January 1998 and May 2016 in the Region of Murcia, Spain. Evaluation of parental SHS and other known prognostic factors (sex, age, white blood cell count at diagnosis, cytogenetics, NCI/Rome Criteria, early response to therapy, and relapse) were assessed for impact on OS, event-free survival (EFS), cumulative incidence of relapse (CIR), and treatment-related mortality (CITRM) using Kaplan-Meier analysis, Cox regression, and Fine-Gray model.

RESULTS

The mean follow-up time was 105.3 months (±66.5). Prenatal exposure to SHS due to parental smoking was highly prevalent. Of the mothers, 44.4% and 55.5% of the fathers smoked at some point during pregnancy. After the child's diagnosis of ALL 39.7% of mothers and 45.9% of fathers reported smoking. The Cox proportional hazards model showed that maternal smoking during pregnancy and after diagnosis (HR = 4.396, 95% CI: 1.173-16.474, p = 0.028); and relapse (HR = 7.919; 95% CI: 2.683-21.868; p < 0.001) are independent prognostic factors in determining survival. The Fine-Gray model showed that maternal smoking during pregnancy and after diagnosis (HR = 14.525, 95% CI: 4.228-49.90, p < 0.001) is an independent prognostic factor in CITRM.

CONCLUSIONS

Persistent SHS worsens OS and TRM in children with ALL. This negative impact contributes to a different prognosis and may possibly provide an exceptional insight into new therapeutic approaches, including environmental aspects such as prevention and smoking cessation to improve survival outcomes.

Bortezomib reinduction chemotherapy in high-risk ALL in first relapse: a report from the Children's Oncology Group

While survival in paediatric acute lymphoblastic leukaemia (ALL) is excellent, survival following relapse is poor. Previous studies suggest proteasome inhibition with chemotherapy improves relapse ALL response rates. This phase 2 Children's Oncology Group study tested the hypothesis that adding the proteasome inhibitor bortezomib to chemotherapy increases complete response rates (CR2). Evaluable patients (n = 135, 103 B-ALL, 22 T-ALL, 10 T-lymphoblastic lymphoma) were treated with reinduction chemotherapy plus bortezomib. Overall CR2 rates were 68 ± 5% for precursor B-ALL patients (<21 years of age), 63 ± 7% for very early relapse (<18 months from diagnosis) and 72 ± 6% for early relapse (18-36 months from diagnosis). Relapsed T-ALL patients had an encouraging CR2 rate of 68 ± 10%. End of induction minimal residual disease (MRD) significantly predicted survival. MRD negative (MRDneg; MRD <0·01%) rates increased from 29% (post-cycle 1) to 64% following cycle 3. Very early relapse, end-of-induction MRDneg precursor B-ALL patients had 70 ± 14% 3-year event-free (EFS) and overall survival (OS) rates, vs. 3-year EFS/OS of 0-3% (P = 0·0001) for MRDpos (MRD ≥0·01) patients. Early relapse patients had similar outcomes (MRDneg 3-year EFS/OS 58-65% vs. MRDpos 10-19%, EFS P = 0·0014). These data suggest that adding bortezomib to chemotherapy in certain ALL subgroups, such as T-cell ALL, is worthy of further investigation. This study is registered at http://www.clinical.trials.gov as NCT00873093.

Comparative features and outcomes between paediatric T-cell and B-cell acute lymphoblastic leukaemia

Contemporary paediatric clinical trials have improved 5-year event-free survival above 85% and 5-year overall survival above 90% in B-cell acute lymphoblastic leukaemia (ALL) in many study groups, whilst outcomes for T-cell ALL are still lagging behind by 5-10% in most studies. Several factors have contributed to this discrepant outcome. First, patients with T-cell ALL are generally older than those with B-cell ALL and, therefore, have poorer tolerance to chemotherapy, especially dexamethasone and asparaginase, and have increased risk of extramedullary relapse. Second, a higher proportion of patients with B-cell ALL have favourable genetic subtypes (eg, ETV6-RUNX1 and high hyperdiploidy), which confer a superior outcome compared with favourable subtypes of T-cell ALL. Third, T-cell ALL blasts are generally more resistant to conventional chemotherapeutic drugs than are B-cell ALL blasts. Finally, patients with B-cell ALL are more amendable to available targeted therapies, such as Philadelphia chromosome-positive and some Philadelphia chromosome-like ALL cases to ABL-class tyrosine kinase inhibitors, and CD19-positive and CD22-postive B-cell ALL cases to a variety of immunotherapies. Several novel treatments under investigation might narrow the gap in survival between T-cell ALL and B-cell ALL, although novel treatment options for T-cell ALL are limited.

Origins and clinical relevance of proteoforms in pediatric malignancies

INTRODUCTION

Cancer changes the proteome in complex ways that reach well beyond simple changes in protein abundance. Genomic and transcriptional variations and post-translational protein modification create functional variants of a protein, known as proteoforms. Childhood cancers have fewer genomic alterations but show equally dramatic phenotypic changes as malignant cells in adults. Therefore, unraveling the complexities of the proteome is even more important in pediatric malignancies. Areas covered: In this review, the biological origins of proteoforms and technological advancements in the study of proteoforms are discussed. Particular emphasis is given to their implication in childhood malignancies and the critical role of cancer-specific proteoforms for the next generation of cancer therapies and diagnostics. Expert opinion: Recent advancements in technology have led to a better understanding of the underlying mechanisms of tumorigenesis. This has been critical for the development of more effective and less harmful treatments that are based on direct targeting of altered proteins and deregulated pathways. As proteome coverage and the ability to detect complex proteoforms increase, the most need for change is in data compilation and database availability to mediate high-level data analysis and allow for better functional annotation of proteoforms.

FxCycle™ Based Ploidy Correlates with Cytogenetic Ploidy in B-Cell Acute Lymphoblastic Leukemia and Is Able to Detect the Aneuploid Minimal Residual Disease Clone

BACKGROUND

Flow cytometry (FCM) is a simple, sensitive, and specific technique that can potentially determine DNA ploidy in B-cell precursor ALL (BCP-ALL) and is complementary to cytogenetics.

METHODS

A prospective FCM DNA ploidy analysis using FxCycle™ Violet (assay sensitivity 0.01%) was done in 125 consecutive new cases of BCP-ALL (90 cases <15 years of age) and compared with corresponding cytogenetic ploidy (karyotyping and/or FISH) data wherever available. This assay was also subsequently evaluated for detection of residual aneuploid clone in few BCP-ALL cases.

RESULTS

Of the total 125 BCP-ALL cases evaluated, flow ploidy analysis revealed diploidy (DI 0.96-1.05) in 44.8% (n = 56), low-hyperdiploidy (DI 1.06 to 1.15) in 13.6% (n = 17), high-hyperdiploidy (DI 1.16-1.39) in 32.8% (n = 41) and near-tetraploidy (DI ≥ 1.80) in 2.4% (n = 3) cases. The high risk sub-group of low-hypodiploidy (DI 0.70 to 0.88)/near-triploidy (DI 1.40 to 1.79) constituted 5.6% (n = 7) cases while there was only one case with haploidy (DI 0.58). Overall, high concordance of 90.4% (n = 113) was noted between the combined cytogenetics ploidy and FCM ploidy. Of the total discordant cases (n = 12), the maximum discordance was seen in the low-hyperdiploid DI subgroup (n = 10), which included seven cases with low DNA index high hyperdiploidy (LDI-HHD). FCM DNA ploidy assay was able to detect the residual clone in all six MRD positive aneuploid cases evaluated.

CONCLUSIONS

FxCycle™ based DNA ploidy ascertains strong correlation with cytogenetic profiles and yields complementary information that can be used by the cytogenetics laboratories or otherwise. © 2019 International Clinical Cytometry Society.

Recent Advances in the Biology and Treatment of T Cell Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

This article provides an overview of the current knowledge regarding the biology and treatment of T cell acute lymphoblastic leukemia (T-ALL) and highlights the most recent findings in this field over the past 5 years.

RECENT FINDINGS

Remarkable progress has been made in the genomic landscape of T-ALL over the past few years. The discovery of activating mutations of NOTCH1 and FBXW7 in a majority of patients has been a seminal observation, with several early phase clinical trials currently exploring these as potential therapeutic targets. Characterization of early T cell precursor ALL, incorporation of minimal residual disease assessment into therapeutic protocols, and use of pediatric-intensive regimens along with judicious use of allogeneic HCT have significantly improved risk stratification and treatment outcomes. Improved risk stratification and the use of novel targeted therapies based on recent genomic discoveries are expected to change the therapeutic landscape of T-ALL and hopefully improve the outcomes of this historically poor prognosis disease.

Reassessment of the Risk-stratified GD-2008 ALL Protocol

OBJECTIVE

To explore the clinical features and outcomes of relapsed childhood acute lymphoblastic leukemia (ALL) at our center, achieve the early detection of risk factors for recurrence and assess the risk-stratified Guangdong (GD)-2008 ALL protocol.

MATERIALS AND METHODS

In total, 59 Chinese childhood ALL patients treated with the GD-2008 ALL protocol who relapsed between July 2008 and March 2015 were enrolled in this study. Their clinical features and outcomes were retrospectively analyzed and compared with those of 218 patients who achieved continuous complete remission.

RESULTS

Of the 285 study participants, 8 died of treatment-related infections or other complications before remission, 218 achieved continuous complete remission, and 59 patients relapsed, yielding a relapse rate of 20.7%. The number of relapsed patients in the standard-risk, intermediate-risk, and high-risk groups were 15 (17.0%), 27 (19.7%), and 17 (32.7%), respectively. Risk factors included age 10 years and above at first diagnosis, white blood cell (WBC) count ≥50×10/L, poor prednisone response, failure to achieve bone marrow complete remission at day 15 of induction chemotherapy. High-risk stratification and a high level (≥0.1%) of minimal residual disease at day 33 were the risk factors for relapse. Multivariate analysis showed that a high WBC at first diagnosis was an independent risk factor for relapse (P=0.000).

CONCLUSION

For the GD-2008 ALL risk stratification based on age and initial WBC, 10 years of age and WBC 50×10/L can be used as cut-offs. Patients at high risk benefited from the GD-2008 ALL protocol. In addition, the impact of minimal residual disease on prognosis should be considered.

Allogeneic Stem Cell Transplantation from HLA-Mismatched Donors for Pediatric Patients with Acute Lymphoblastic Leukemia Treated According to the 2003 BFM and 2007 International BFM Studies: Impact of Disease Risk on Outcomes

Allogeneic hematopoietic stem cell transplantation (HSCT) is beneficial for pediatric patients with relapsed or (very) high-risk acute lymphoblastic leukemia (ALL) in remission. A total of 1115 consecutive patients were included in the ALL SCT 2003 BFM study and the ALL SCT 2007 I-BFM study and were stratified according to relapse risk (standard versus high versus very high risk of relapse) and donor type (matched sibling versus matched donor versus mismatched donor). A total of 148 patients (60% boys; median age, 8.7 years; B cell precursor ALL, 75%) were transplanted from mismatched donors, which was defined as either less than 9/10 HLA-compatible donors or less than 5/6 unrelated cord blood after myeloablative conditioning regimen (total body irradiation based, 67%) for high relapse risk (HRR; n = 42) or very HRR (VHRR) disease (n = 106). The stem cell source was either bone marrow (n = 31), unmanipulated peripheral stem cells (n = 28), T cell ex vivo depleted peripheral stem cells (n = 59), or cord blood (n = 25). The median follow-up was 5.1 years. The 4-year rates of overall survival (OS) and event-free survival were 56% ± 4% and 52% ± 4%, respectively, for the entire cohort. Patients transplanted from mismatched donors for HRR disease obtained remarkable 4-year OS and event-free survival values of 82% ± 6% and 80% ± 6%, respectively, whereas VHRR patients obtained values of 45% ± 5% and 42% ± 5% (P < .001), respectively. The cumulative incidence of relapse was 29% ± 4% and that of nonrelapse mortality 19% ± 3%. The cumulative incidence of limited and extensive chronic graft-versus-host disease was 13% ± 3% and 15% ± 4%, respectively, among the 120 patients living beyond day 100. Multivariate analysis showed that OS was lower for transplanted VHRR patients (P = .002; hazard ratio [HR], 3.62; 95% confidence interval [CI], 1.60 to 8.20) and for patients beyond second complete remission (CR2) versus first complete remission (P < .001; HR, 3.68; 95% CI, 1.79 to 7.56); relapse occurred more frequently in patients with VHRR disease (P = .026; HR, 3.30; 95% CI, 1.16 to 9.60) and for those beyond CR2 (P = .005; HR, 4.16; 95% CI, 1.52 to 10.59). Nonrelapse mortality was not significantly higher for cytomegalovirus-positive recipients receiving cytomegalovirus-negative grafts (P = .12; HR, 1.96; 95% CI, .84 to 4.58). HSCT with a mismatched donor is feasible in pediatric ALL patients but leads to inferior results compared with HSCT with better matched donors, at least for patients transplanted for VHRR disease. The results are strongly affected by disease status. The main cause of treatment failure is still relapse, highlighting the urgent need for interventional strategies after HSCT for patients with residual leukemia before and/or after transplantation.

Single-cell developmental classification of B cell precursor acute lymphoblastic leukemia at diagnosis reveals predictors of relapse

Insight into the cancer cell populations that are responsible for relapsed disease is needed to improve outcomes. Here we report a single-cell-based study of B cell precursor acute lymphoblastic leukemia at diagnosis that reveals hidden developmentally dependent cell signaling states that are uniquely associated with relapse. By using mass cytometry we simultaneously quantified 35 proteins involved in B cell development in 60 primary diagnostic samples. Each leukemia cell was then matched to its nearest healthy B cell population by a developmental classifier that operated at the single-cell level. Machine learning identified six features of expanded leukemic populations that were sufficient to predict patient relapse at diagnosis. These features implicated the pro-BII subpopulation of B cells with activated mTOR signaling, and the pre-BI subpopulation of B cells with activated and unresponsive pre-B cell receptor signaling, to be associated with relapse. This model, termed 'developmentally dependent predictor of relapse' (DDPR), significantly improves currently established risk stratification methods. DDPR features exist at diagnosis and persist at relapse. By leveraging a data-driven approach, we demonstrate the predictive value of single-cell 'omics' for patient stratification in a translational setting and provide a framework for its application to human cancer.

No prognostic significance of immunophenotypic changes at the end of remission induction therapy in children with B-lineage acute lymphoblastic leukemia

Detection of aberrant antigen expression in acute lymphoblastic leukemia (ALL) by flow cytometric is proposed for the quantification of minimal residual disease (MRD). There are few studies that investigate the stability of the antigen expression in children with B lineage ALL at the end of remission induction therapy and determine its prognostic impact. Between 2010 and 2015, 691 bone marrow specimens of childhood ALL were sent at diagnosis for immunophenotypic characterization, and follow-up samples for MRD were analyzed on day 33. Of these, 155 patients with MRD more than or equal to 0.01% were eligible for the study. Immunophenotypic studies were performed by multiparametric flow cytometry using four-colour monoclonal antibody combinations. Overall, 86 of 155 (55.5%) cases showed phenotype shifts at least one marker. CD19 was the most stable markers. By contrast, CD20 was significantly different between diagnosis and day 33 in nearly one third of the cases. Shifts of antigen expression was not significantly associated with EFS, RFS or OS (P > 0.05). Multivariate analysis showed that WBC and BCR-ABL have independent prognostic value in childhood ALL. Changes in antigen expressions were commonly occurred at the end of induction and not associated with prognostic value in patients whose MRD were positive on day 33.