Progress and Prospects in Pediatric Leukemia

A novel inhibitor of the mitochondrial respiratory complex I with uncoupling properties exerts potent antitumor activity

Cancer cells are highly dependent on bioenergetic processes to support their growth and survival. Disruption of metabolic pathways, particularly by targeting the mitochondrial electron transport chain complexes (ETC-I to V) has become an attractive therapeutic strategy. As a result, the search for clinically effective new respiratory chain inhibitors with minimized adverse effects is a major goal. Here, we characterize a new OXPHOS inhibitor compound called MS-L6, which behaves as an inhibitor of ETC-I, combining inhibition of NADH oxidation and uncoupling effect. MS-L6 is effective on both intact and sub-mitochondrial particles, indicating that its efficacy does not depend on its accumulation within the mitochondria. MS-L6 reduces ATP synthesis and induces a metabolic shift with increased glucose consumption and lactate production in cancer cell lines. MS-L6 either dose-dependently inhibits cell proliferation or induces cell death in a variety of cancer cell lines, including B-cell and T-cell lymphomas as well as pediatric sarcoma. Ectopic expression of Saccharomyces cerevisiae NADH dehydrogenase (NDI-1) partially restores the viability of B-lymphoma cells treated with MS-L6, demonstrating that the inhibition of NADH oxidation is functionally linked to its cytotoxic effect. Furthermore, MS-L6 administration induces robust inhibition of lymphoma tumor growth in two murine xenograft models without toxicity. Thus, our data present MS-L6 as an inhibitor of OXPHOS, with a dual mechanism of action on the respiratory chain and with potent antitumor properties in preclinical models, positioning it as the pioneering member of a promising drug class to be evaluated for cancer therapy. MS-L6 exerts dual mitochondrial effects: ETC-I inhibition and uncoupling of OXPHOS. In cancer cells, MS-L6 inhibited ETC-I at least 5 times more than in isolated rat hepatocytes. These mitochondrial effects lead to energy collapse in cancer cells, resulting in proliferation arrest and cell death. In contrast, hepatocytes which completely and rapidly inactivated this molecule, restored their energy status and survived exposure to MS-L6 without apparent toxicity.

The global burden of childhood and adolescent leukaemia and attributable risk factors: An analysis of the Global Burden of Disease Study 2019

Background

Aim of this study is to estimate the burden of leukaemia in children and adolescents, as well as the socio-demographic index (SDI), for 21 regions around the world from 1990 to 2019.

Methods

We also conducted an analysis of the Joinpoint model to estimate the time trend of childhood and adolescent leukaemia incidence, death, and disability-adjusted life years (DALYs) rate and age-standardised rates (ASR) of leukaemia.

Results

According to our analysis, the middle SDI experienced the highest decrease in incidence rate between 1990 and 2019, with an average annual percent change (AAPC) of -2.8 (95% confidence interval (CI) = -3.0, -2.6, P < 0.05). We showed that DALYs of children leukaemia is 155.98 (95% uncertainty interval (UI) = 127.18, 182.64) for global male, however, global female leukaemia DALYs is 117.65 (95% UI = 102.07, 132.70).

Conclusions

Despite the observed decline in the incidence, mortality, and DALYs of leukaemia over the last three decades, the burden of childhood and adolescent leukaemia remains high, particularly in areas with lower SDI.

Integrating rapamycin with novel PI3K/Akt/mTOR inhibitor microRNAs on NOTCH1-driven T-cell acute lymphoblastic leukemia (T-ALL)

Introduction

The PI3K/AKT/mTOR signaling pathway plays a significant role in the development of T-cell acute lymphoblastic leukemia (T-ALL). Rapamycin is a potential therapeutic strategy for hematological malignancies due to its ability to suppress mTOR activity. Additionally, microRNAs (miRNAs) have emerged as key regulators in T-ALL pathophysiology and treatment. This study aimed to investigate the combined effects of rapamycin and miRNAs in inhibiting the PI3K/AKT/mTOR pathway in T-ALL cells.

Methods

Bioinformatic algorithms were used to find miRNAs that inhibit the PI3K/AKT/mTOR pathway. Twenty-five bone marrow samples were collected from T-ALL patients, alongside five control bone marrow samples from non-leukemia patients. The Jurkat cell line was chosen as a representative model for T-ALL. Gene and miRNA expression levels were assessed using quantitative real-time PCR (qRT-PCR). Two miRNAs exhibiting down-regulation in both clinical samples and Jurkat cells were transfected to the Jurkat cell line to investigate their impact on target gene expression. Furthermore, in order to evaluate the potential of combination therapy involving miRNAs and rapamycin, apoptosis and cell cycle assays were carried out.

Results

Six miRNAs (miR-3143, miR-3182, miR-99a/100, miR-155, miR-576-5p, and miR-501- 3p) were predicted as inhibitors of PI3K/AKT/mTOR pathway. The expression analysis of both clinical samples and the Jurkat cell line revealed a simultaneous downregulation of miR-3143 and miR-3182. Transfection investigation demonstrated that the exogenous overexpression of miR-3143 and miR-3182 can effectively inhibit PI3K/AKT/mTOR signaling in the Jurkat cell line. Moreover, when used as a dual inhibitor along with rapamycin, miR-3143 and miR-3182 significantly increased apoptosis and caused cell cycle arrest in the Jurkat cell line.

Conclusion

These preliminary results highlight the potential for improving T-ALL treatment through multi-targeted therapeutic strategies involving rapamycin and miR-3143/miR-3182.

Oral Manifestations: A Warning-Sign in Children with Hematological Disease Acute Lymphocytic Leukemia

Acute lymphocytic leukemia (ALL) is the most frequent form of all childhood leukemias, mostly affecting children between 2 and 4 years old. Oral symptoms, such as mouth ulcers, mucositis, xerostomia, Herpes or Candidiasis, gingival enlargement and bleeding, petechiae, erythema, mucosal pallor and atrophic glossitis, are very common symptoms of ALL and can be early signs of the disease. Secondary and tertiary complications, a direct effect of chemo and radiotherapy, are associated with more severe bleeding, higher susceptibility to infections, ulcerations, inflammation of the mucous membranes, osteoradionecrosis, xerostomia, taste alterations, trismus, carious lesions and dental abnormalities. Immunotherapy, though less toxic, causes oral dysesthesia and pain. Overall, the effects in the oral cavity are transient but there are long-term consequences like caries, periodontal disease and tooth loss that impair endodontic and orthodontic treatments. Also, dental abnormalities resulting from disturbed odontogenesis are known to affect a child's quality of life. The medical dentist should identify these complications and perform appropriate oral care in tandem with other health professionals. Thus, poor oral hygiene can lead to systemic ALL complications. The aim of this review is to describe the oral complications in children with ALL who are undergoing chemo, radio or immunotherapy.

Gene-Based Natural Killer Cell Therapies for the Treatment of Pediatric Hematologic Malignancies

Pediatric blood cancers are among the most common malignancies that afflict children. Intensive chemotherapy is not curative in many cases, and novel therapies are urgently needed. NK cells hold promise for use as immunotherapeutic effectors due to their favorable safety profile, intrinsic cytotoxic properties, and potential for genetic modification that can enhance specificity and killing potential. NK cells can be engineered to express CARs targeting tumor-specific antigens, to downregulate inhibitory and regulatory signals, to secrete cytokine, and to optimize interaction with small molecule engagers. Understanding NK cell biology is key to designing immunotherapy for clinical translation.

Experience of the Spanish Group for Hematopoietic Transplantation (GETMON-GETH) in allogenic Hematopoietic stem cell Transplantation in Philadelphia acute lymphoblastic leukemia

INTRODUCTION

Outcomes in patients diagnosed of acute lymphoblastic leukemia with Philadelphia chromosome (Ph-ALL) remains unfavourable compared to other subtypes of acute lymphoblastic leukemia despite improvements in drug treatments as well as advances in hematopoietic stem cell transplantation (HSCT).

PATIENTS AND METHODS

The role of allogeneic HSCT in Ph-ALL patients has been analysed through a multicentric study where data belonging to 70 patients diagnosed of this entity in different centers that received HSCT between years 1998 and 2014, were reported by the Grupo Español de Trasplante Hematopoyético (GETH).

RESULTS

The performance of HSCT from year 2004, in first complete remission (CR) status with thymoglobulin (ATG) based conditioning had a favorable impact on overall survival (OS). HSTC performance from year 2004, in first CR with ATG-based conditioning in addition to acute graft versus host disease (aGvHD) development, increased event free survival (EFS). Treatment with imatinib as well as undetectable minimal residual disease (MRD) prior to HSCT, combined with aGvHD, reduced risk of relapse (RR). Patient age less than 10 years when HSCT, first CR and ATG-based conditioning were associated to a lower transplant related mortality (TRM).

CONCLUSIONS

Patients that could achieve first CR that also received ATG-based conditioning had a better OS and EFS, so HSCT should be considered for this group of patients.

An Overview of Conventional Drugs and Nano Therapeutic Options for the Treatment and Management of Pediatric Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a common form of pediatric cancer affecting the lymphoblast, a type of white blood cell found in the bone marrow. In this disease, the normal lymphoblast cells transform into leukemic cells and subsequently enter the bloodstream. Leukemic cells found in patients with ALL have shown differences in cholesterol uptake and utilization. Current treatment consists of chemotherapy, chimeric antigen receptor (CAR) therapy, and hematopoietic stem cell transplantation (HSCT). In addition, minimal residual disease (MRD) has become an effective tool in measuring treatment efficacy and the potential for relapse. Chemotherapy resistance remains a significant barrier in the treatment of ALL. Biomarkers such as an upregulated Akt signaling pathway and an overexpressed VLA-4 integrin-protein have been associated with drug resistance. Nanoparticles have been used to favorably alter the pharmacokinetic profile of conventional drug agents. These drug-delivery systems are designed to selectively deliver their drug payloads to desired targets. Therefore, nanoparticles offer advantages such as improved efficacy and reduced toxicity. This review highlights conventional treatment options, distinctive characteristics of pediatric ALL, therapeutic challenges encountered during therapy, and the key role that nanotherapeutics play in the treatment of ALL.

The relationship between the care burden and quality of life of parents who have children with hematological problems and their perceived social support

PURPOSE

The purpose of this study was to examine the interrelationship of the caregiver burden, perceived social support, and quality of life of parents who have children with hematological problems.

DESIGN AND METHODS

The design and methods included a descriptive study with 141 parents of children with hematological problems. The introductory information form, the Zarit Burden Interview (ZBI), multidimensional scale of perceived social support (MSPSS), and the EUROHIS-QOL.8 (WHOQOL-8) scale were used as data collection tools. The data obtained were analyzed using descriptive statistics and structural equation models.

RESULTS

As a result of the conducted correlation analysis, it was determined that there was a positive correlation between parents' perceptions of social support and their quality of life, and a negative correlation between their perceptions of social support and the caregiver burden (p < 0.05). As a result of the structural equation model, it was determined that the social support received by the parents had a significant effect on their caregiver burden (β = -0.40; p < 0.05), and their quality of life (β = 0.42; p < 0.05).

CONCLUSIONS

The conclusion formed was that it can be said that parents' perceptions of social support affect their caregiver burden and quality of life. Parents with high perceptions of social support perceive the burden of caregiver to be low and their quality of life to be high.

PRACTICE IMPLICATIONS

The practice implications are that healthcare professionals can contribute to reducing the caregiver burden and improving the quality of life of parents, by strengthening the social support systems of parents with sick children.

Impact of Perioperative Absolute Neutrophil Count on Central Line-Associated Bloodstream Infection in Children With Acute Lymphoblastic and Myeloid Leukemia

Background

There is lack of evidence concerning safety of placement of tunneled central venous catheters (TCVCs) in neutropenic children with acute leukemias. Here, we evaluate the impact of absolute neutrophil count (ANC) at the time of TCVC placement on development of central line-associated bloodstream infections (CLABSI) in children with lymphoblastic (ALL) or myeloid leukemia (AML).

Materials and Methods

A retrospective observational study of children undergoing TCVC placement at a tertiary referral hospital between January 2000 and December 2019 was performed. Traditional and competing-risks regression models were used to estimate the effect of perioperative ANC on development of CLABSI.

Results

A total of 350 children (median age 6.4 [IQR: 3.1–10.9] years) underwent 498 consecutive TCVC implantations in neutropenic (n = 172, 34.5%) and non-neutropenic conditions (n = 326, 65.5%). The median length of observation per TCVC was 217.1 (IQR: 116.1–260.5) days with a total of 99,681 catheter days (CD). There were no differences in early (within first 30 days after TCVC placement) and overall CLABSI rates between neutropenic and non-neutropenic patients (HR 1.250, p = 0.502; HR 1.633, p = 0.143). We identified female sex (HR 2.640, p = 0.006) and the use of TCVC for treatment of relapsed leukemia (HR 4.347, p < 0.0001) as risk factors for early CLABSI and the use of double-lumen catheters (HR 2.607, p = 0.003) and use of TCVCs during leukemia relapse (HR 2.004, p = 0.005) for overall study period.

Conclusion

The placement of TCVC in children with neutropenia undergoing anticancer therapy for acute leukemia is safe and not associated with an elevated rate of CLABSI.

Role of matrix metalloproteinase MMP-2, MMP-9 and tissue inhibitor of metalloproteinase (TIMP-1) in the clinical progression of pediatric acute lymphoblastic leukemia

BACKGROUND

Matrix metalloproteinases (MMPs) play a crucial role in cancer progression and metastasis, however their role in pediatric Acute lymphoblastic leukemia (ALL) is still unrevealed.

METHODS

The diagnostic, prognostic and predictive value of tissue inhibitor of metalloproteinase (TIMP-1), MMP-2, MMP-9 and CD34+CD38- cancer stem cells (CSCs) were assessed in bone marrow (BM) samples of 76 ALL children using Flow Cytometry analysis.

RESULTS

There was a significant increase in TIMP-1 [1.52 (0.41-10) versus 0.91(0.6-1.12); respectively, p < 0.001], and CSCs CD34⁺CD38^- [1 (0.03-18.6) versus 0.3 (0.01-1.1), p < 0.001] expression in ALL patients compared to controls. While there were no significant differences regarding MMP-2 and MMP-9 expression between the two groups. The sensitivity, specificity, area under curve (AUC) of MMP-2 were (80.3%, 53.3% and 0.568, p = 0.404), and of MMP-9 were (53.9%, 40% and 0.660, p = 0.053). While that of TIMP-1 were (78.9%, 100% and 0.892, p < 0.001), and that of CD34⁺CD38^- CSCs were (78.9%, 73.3% and 0.855, p < 0.001). Increased TIMP-1 expression associated with the high-risk disease (p < 0.001). CD34⁺CD38^- CSCs and MMP-2 overexpression associated with MRD at day-15, increased BM blast cell count at diagnosis and at day-15 (p < 0.05). TIMP-1 overexpression is associated with shorter DFS and OS rates (p = 0.009 and p = 0.048). Multivariate logistic regression analysis showed that both TIMP-1 [OR: 4.224, p = 0.046], and CD34⁺CD38^- CSCs [OR: 6.873, p = 0.005] could be potential independent diagnostic factors for pediatric ALL.

CONCLUSION

TIMP-1 and CD34⁺CD38^- CSCs could be possible useful diagnostic markers for pediatric ALL. Also, TIMP-1 is a promising prognostic marker for poor outcome of the patients.

Expression of YY1 in pro-B and T phenotypes correlation with poor survival in pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, constituting 80% of all acute leukemias in minors. Despite the increase in the success of therapies, disease-free survival is over 80% in most cases. For the remaining 20% of patients, new strategies are needed to allow us to know and select those at greatest risk of relapse. We evaluated by immunohistochemistry the expression of the transcription factor YY1 and found that it is overexpressed in peripheral blood leukemia cells of pediatric patients with ALL with Pro-B and T phenotype compared to control samples. Over expression of YY1 was associated with a significantly lower chance of survival. We also evaluated by RT-PCR in bone marrow samples from ALL pediatric patients the association of YY1 expression with the percentage of blasts. High levels of YY1 were present in samples with higher percent of blasts in these patients. In addition, ALL pediatric patients with a poor response to therapy had higher levels at the nuclear level of YY1 than those who responded well to chemotherapy. In conclusion, our data suggest that YY1 could serve in pediatric ALL as markers of evolution and response for this disease, mainly in patients with pro-B and T immunophenotype. It is also suggested that YY1 is implicated in the expanse of blast in these patients.

Low IL-23 levels in peripheral blood and bone marrow at diagnosis of acute leukemia in children increased with the elimination of leukemic burden

IL‐23 is an IL‐12 cytokine family member with pleiotropic functions that regulates tumour growth in various cancer types, exhibiting both anti‐tumorigenic and pro‐tumorigenic properties. Preclinical studies have shown a potential anti‐leukemic action on childhood B‐ALL cells. The study involved 65 children with acute leukemia [59 patients with acute lymphoblastic leukemia (ALL) and 6 patients with acute myeloid leukemia (AML)] and 27 healthy controls. Using an enzyme‐linked immunosorbent assay, we aimed to determine the IL‐23 levels in the peripheral blood (PB) and bone marrow (BM) of patients at diagnosis and at the end of the induction therapy (EIT). PB IL‐23 levels were lower in leukemia patients compared to the healthy controls. In all acute leukemia patients, IL‐23 levels were significantly lower at diagnosis both in PB (P = .015) and in BM (P = .037) compared to the PB and BM concentrations at the EIT. The same pattern was present in both subgroups of ALL and AML patients. The high leukemic burden at diagnosis was related with lower IL‐23 levels, which were increased with the disease remission. Considering the anti‐leukemic potential of this cytokine, the elevation of the IL‐23 concentration at the disease remission indicates a beneficial role of IL‐23 in paediatric acute leukemia.

Curcumin induces apoptosis by inhibiting BCAT1 expression and mTOR signaling in cytarabine‑resistant myeloid leukemia cells

Cytarabine is a key chemotherapy drug for treating leukemia; however, chemotherapy‑induced multidrug resistance is a major cause of therapy failure or tumor recurrence. Current medical treatment strategies still cannot address the issue of multidrug resistance phenotypes in the treatment of leukemia. Curcumin counteracts tumor development by inducing apoptosis in cytarabine‑resistant acute myeloid leukemia cells. Branched‑chain amino acid transaminase 1 (BCAT1), an aminotransferase enzyme, acts on branched‑chain amino acids. Moreover, the aberrant expression of BCAT1 has been observed in numerous cancer cells, and BCAT1 serves a critical role in the progression of myeloid leukemia. BCAT1 can interfere with cancer cell proliferation by regulating mTOR‑mediated mitochondrial biogenesis and function. The present study aimed to investigate whether curcumin induces apoptosis by regulating BCAT1 expression and mTOR signaling in cytarabine‑resistant myeloid leukemia cells. Four leukemia cell lines and three primary myeloid leukemia cells were treated with curcumin, and the expression and activity of BCAT1 and mTOR were investigated by reverse transcription‑quantitative PCR, western blotting and α‑KG quantification assay. The results demonstrated that curcumin inhibited BCAT1 expression in Kasumi‑1, KG‑1, HL60, cytarabine‑resistant HL60, and cytarabine‑resistant primary myeloid leukemia cells. Notably, tetrahydrocurcumin, a major metabolite of curcumin, and cytarabine had no inhibitory effect on BCAT1 expression. Furthermore, BCAT1 and mTOR signaling may modulate each other in cytarabine‑resistant HL60 cells. The present results indicated that curcumin may induce apoptosis by inhibiting the BCAT1 and mTOR pathways. Thus, understanding the mechanism underlying curcumin‑induced apoptosis in cytarabine‑resistant cells can support the development of novel drugs for leukemia.

MicroRNA as a Prognostic and Diagnostic Marker in T-Cell Acute Lymphoblastic Leukemia

T cell acute lymphoblastic leukemia (T-ALL) is a biologically and genetically heterogeneous disease with a poor prognosis overall and several subtypes. The neoplastic transformation takes place through the accumulation of numerous genetic and epigenetic abnormalities. There are only a few prognostic factors in comparison to B cell precursor acute lymphoblastic leukemia, which is characterized by a lower variability and more homogeneous course. The microarray and next-generation sequencing (NGS) technologies exploring the coding and non-coding part of the genome allow us to reveal the complexity of the genomic and transcriptomic background of T-ALL. miRNAs are a class of non-coding RNAs that are involved in the regulation of cellular functions: cell proliferations, apoptosis, migrations, and many other processes. No miRNA has become a significant prognostic and diagnostic factor in T-ALL to date; therefore, this topic of investigation is extremely important, and T-ALL is the subject of intensive research among scientists. The altered expression of many genes in T-ALL might also be caused by wide miRNA dysregulation. The following review focuses on summarizing and characterizing the microRNAs of pediatric patients with T-ALL diagnosis and their potential future use as predictive factors.

Targeting EZH2-mediated methylation of histone 3 inhibits proliferation of pediatric acute monocytic leukemia cells in vitro

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and a catalytic subunit of the polycomb repressive complex 2 (PRC2) that catalyzes the mono-, di-, and tri-methylation of histone H3 at Lys 27 (H3K27me3) to facilitate chromatin-remodeling and gene-silencing functions. Previous reports showed a significant association of EZH2 aberrations in pediatric cancers, such as soft tissue sarcomas and glioblastoma. Recent reports in human subjects and animal models have also suggested a central role of EZH2 in the induction and progression of acute myeloid leukemia. In this study, we aimed to investigate the molecular status of EZH in cell lines derived from distinct pediatric leukemia to assess the efficacy of targeting EZH2 to suppress cancer cell survival and proliferation. Our results showed that EZH2 protein is overexpressed in the pediatric monocytic cell-line THP-1, but not in other leukemia-derived cell lines MV4;11 and SEM. Screening a panel of methyltransferase inhibitors revealed that three inhibitors; GSK126, UNC1999 and EPZ-5687 are the most potent inhibitors that suppressed EZH2 activity selectively on lysine 27 which resulted in increased apoptosis and inhibition of AKT and ERK protein phosphorylation in THP-1 cells. Our data demonstrated a significant increase in apoptosis in cells treated with drug combination (EZH2i and selinexor) compared to EZH2i inhibitors alone. Taken together, our data provide initial evidence that targeting EZH2 is a promising therapeutic strategy for the treatment of subtypes of pediatric AML. Also, combining EZH2 inhibitors with selinexor may increase the treatment efficacy in these patients.

Infantile leukemia-What factors determine its distinct biological nature? Clinicopathological study of 78 cases

INTRODUCTION

Infantile leukemia encompasses a heterogeneous group which needs stratifying for treatment selection.

METHODS

We collected 78 cases of infantile leukemia and retrospectively analyzed their clinicopathological data.

RESULTS

Infantile leukemia featured a ratio of acute myeloid leukemia (AML) to B-lymphoblastic leukemia (B-ALL) of 1:2, with a better survival for AML than B-ALL (median survival 36 vs 24 months). When stratified by age, "early" infantile B-ALL (2-6 months) showed a high rate of KMT2A rearrangement (100%), similar to the rate seen in congenital B-ALL (1 month) (100%) and higher than seen in "late" infantile B-ALL (≥7 months) (68%). The three categories of infantile B-ALL exhibited an age-dependent increase in survival (median survival 8.5, 24, and >24 months, respectively). The age-dependent survival benefit remained after excluding the cases negative for KMT2A rearrangement. Conversely, infantile AML lacked an age-dependent pattern of survival.

CONCLUSION

The clinical outcome of infantile leukemia depends on the type of leukemia. Given the age-dependent survival, infantile B-ALL can be divided into three subcategories.

[Experience of the Spanish Group for Hematopoietic Transplantation (GETMON-GETH) in allogenic hematopoietic stem cell transplantation in Philadelphia acute lymphoblastic leukemia]

INTRODUCTION

Outcomes in patients diagnosed of acute lymphoblastic leukemia with Philadelphia chromosome (Ph-ALL) remains unfavourable compared to other subtypes of acute lymphoblastic leukemia despite improvements in drug treatments as well as advances in hematopoietic stem cell transplantation (HSCT).

PATIENTS AND METHODS

The role of allogeneic HSCT in Ph-ALL patients has been analysed through a multicentric study where data belonging to 70 patients diagnosed of this entity in different center that received HSCT between years 1998 and 2014, were reported by the Grupo Español de Trasplante Hematopoyético (GETH).

RESULTS

The performance of HSCT from year 2004, in first complete remission (CR) status with thymoglobulin (ATG) based conditioning had a favorable impact on overall survival (OS). HSTC performance from year 2004, in first CR with ATG-based conditioning in addition to acute graft versus host disease (aGvHD) development, increased event free survival (EFS). Treatment with imatinib as well as undetectable minimal residual disease (MRD) prior to HSCT, combined with aGvHD, reduced risk of relapse (RR). Patient age less than 10 years when HSCT, first CR and ATG-based conditioning were associated to a lower transplant related mortality (TRM).

CONCLUSIONS

Patients that could achieve first CR that also received ATG-based conditioning had a better OS and EFS, so HSCT should be considered for this group of patients.

Leukaemia Infection Diagnosis and Intestinal Flora Disorder

Leukaemia is the most common malignant tumor in childhood and can be cured by chemotherapy. Infection is an important cause of treatment-related death and treatment failure in childhood leukaemia. Recent studies have shown that the correlation between the occurrence of leukaemia infection and the intestinal flora has attracted more and more attention. Intestinal flora can affect the body's physiological defense and immune function. When intestinal microflora disorder occurs, metabolites/microorganisms related to intestinal flora alterations and even likely the associated morpho-functional alteration of the epithelial barrier may be promising diagnostic biomarkers for the early diagnosis of leukaemia infection. This review will focus on the interaction between leukaemia infection and intestinal flora, and the influence of intestinal flora in the occurrence and development of leukaemia infection.

Development and Evaluation of a Leukemia Diagnosis System Using Deep Learning in Real Clinical Scenarios

Leukemia is the most common malignancy affecting children. The morphologic analysis of bone marrow smears is an important initial step for diagnosis. Recent publications demonstrated that artificial intelligence is able to classify blood cells but a long way from clinical use. A total of 1,732 bone marrow images were used for the training of a convolutional neural network (CNN). New techniques of deep learning were integrated and an end-to-end leukemia diagnosis system was developed by using raw images without pre-processing. The system creatively imitated the workflow of a hematologist by detecting and excluding uncountable and crushed cells, then classifying and counting the remain cells to make a diagnosis. The performance of the CNN in classifying WBCs achieved an accuracy of 82.93%, precision of 86.07% and F1 score of 82.02%. And the performance in diagnosing acute lymphoid leukemia achieved an accuracy of 89%, sensitivity of 86% and specificity of 95%. The system also performs well at detecting the bone marrow metastasis of lymphoma and neuroblastoma, achieving an average accuracy of 82.93%. This is the first study which included a wider variety of cell types in leukemia diagnosis, and achieved a relatively high performance in real clinical scenarios.

Assessment of chimerism and immunomodulation to prevent post-transplantation relapse in childhood acute myeloblastic leukemia: is it the right approach?

Relapse of acute myeloblastic leukemia (AML) after first allogenic hematopoietic stem-cell transplantation (allo-HSCT) is a fatal complication. Sixty-five children transplanted for AML were included in a prospective national study from June 2005 to July 2008 to explore the feasibility of preemptive immune modulation based on the monitoring of blood chimerism. Relapse occurred in 23 patients (35%). The median time between the last complete chimerism and relapse was 13.5 days (2-138). Prompt discontinuation of cyclosporin and the administration of donor lymphocyte infusions (DLIs) based on chimerism monitoring failed as a preemptive tool, either for detecting relapse or certifying long-term remission.

GEM on proliferation and apoptosis of childhood AL cells through inhibiting c-myc expression by upregulating miR-125a-3p

Effect of gemcitabine (GEM) on proliferation and apoptosis of childhood acute leukemia (AL) cells and the mechanism of action were investigated. Bone marrow and peripheral blood of 18 newly diagnosed children with childhood AL admitted to Yidu Central Hospital of Weifang were selected, and the miR-125a-3p level in peripheral blood of healthy children and children with AL was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Leukemia cells from the bone marrow of children with AL were primarily cultured and purified to observe the morphology. miR-125a-3p mimic was transfected into childhood AL cells. The cells were randomly divided into three groups: control group, GEM group and GEM + miR-125a-3p mimic group. 5-ethynyl-2′-deoxyuridine (EdU) staining assay was chosen to detect the proliferation of childhood AL cells in each group. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining assay was adopted to determine apoptosis of childhood AL cells. The protein level of c-myc was measured via western blotting. Compared with that in the healthy children, the level of miR-125a-3p in the peripheral blood of children with AL was remarkably decreased. Compared with those in the control group, GEM inhibited proliferation and promoted apoptosis of childhood AL cells, and impeded the protein expression of c-myc in these cells. Compared with those in the GEM group, GEM + miR-125a-3p mimic notably reduced the proliferation and enhanced apoptosis of cells, and the protein expression of c-myc in cells was overtly reduced. The level of miR-125a-3p in peripheral blood of children with AL is obviously decreased. It is suggested in this study that GEM can inhibit the proliferation and promote apoptosis of childhood AL cells, and the mechanism may be related to upregulated miR-125a-3p inhibiting the expression of c-myc.

Role of Vitamins A and D in BCR-ABL Arf-/- Acute Lymphoblastic Leukemia

The effects of vitamin A and/or vitamin D deficiency were studied in an Arf^−/− BCR-ABL acute lymphoblastic leukemia murine model. Vitamin D sufficient mice died earlier (p = 0.003) compared to vitamin D deficient (VDD) mice. Vitamin A deficient (VAD) mice fared worst with more rapid disease progression and decreased survival. Mice deficient for vitamins A and D (VADD) had disease progression similar to VAD mice. Regulatory T cells, previously shown to associate with poor BCR-ABL leukemia control, were present at higher frequencies among CD4⁺ splenocytes of vitamin A deficient vs. sufficient mice. In vitro studies demonstrated 1,25-dihydroxyvitamin D (1,25(OH)₂VD₃) increased the number of BCR-ABL ALL cells only when co-cultured with bone marrow stroma. 1,25(OH)₂VD₃ induced CXCL12 expression in vivo and in vitro in stromal cells and CXCL12 increased stromal migration and the number of BCR-ABL blasts. Vitamin D plus leukemia reprogrammed the marrow increasing production of collagens, potentially trapping ALL blasts. Vitamin A (all trans retinoic acid, ATRA) treated leukemic cells had increased apoptosis, decreased cells in S-phase, and increased cells in G₀/G₁. ATRA signaled through the retinoid X receptor to decrease BCR-ABL leukemic cell viability. In conclusion, vitamin A and D deficiencies have opposing effects on mouse survival from BCR-ABL ALL.

Ocular Manifestations of Leukemia and Results of Treatment with Intravitreal Methotrexate

Ocular involvement in leukemia is considered rare. Ocular symptoms can be the presenting signs of leukemia, they can appear after diagnosis has been established, or they can be the first manifestation of a relapse after remission. We report, to the best of our knowledge for the first time, the ocular manifestation of a series of patients with ocular leukemia and the result of their treatment with intravitreal methotrexate (MTX) injections. This is a retrospective cohort study. The medical records of 12 consecutive patients with ocular leukemia (24 eyes, 11 eyes treated with MTX) treated at the Sheba Medical Center from January 2010 to December 2017 were retrospectively reviewed. Details on ocular inflammatory reaction and tumor cell infiltration at presentation and the end of follow-up were recorded as main outcome measures. The 12 patients included 7 women and 5 men (mean age ± standard deviation at diagnosis 25.92 ± 23.91 years, range 2-82 years). Eleven eyes of 6 patients were treated with intravitreal MTX injections. The indication for treatment was biopsy proven, tumor cell infiltration. The mean number of MTX injections was 3.37 ± 5.35 (range 1-18). The mean follow-up was 27.08 ± 36.79 months (range 1-93). All treated eyes showed improvement in the inflammatory reaction and tumor cell infiltration. In conclusion we found that Intravitreal MTX injections may be an effective therapeutic approach for eyes with intraocular leukemic tumor cell infiltration.

Cancer Stem Cells in the Development of Novel Therapeutics for Refractory Pediatric Leukemia

Although treatment strategies for pediatric leukemia have improved overall survival rates in the recent past, relapse rates in certain subgroups such as infant leukemia remain unacceptably high. Despite undergoing extensive chemotherapy designed to target the rapidly proliferating leukemia cells, many of these children experience relapse. In refractory leukemia, the existence of cell populations with stemness characteristics, termed leukemia stem cells (LSCs), which remain quiescent and subsequently replenish the blast population, has been described. A significant body of evidence exists, derived largely from xenograft models of adult acute myeloid leukemia, to support the idea that LSCs may play a fundamental role in refractory disease. In addition, clinical studies have also linked LSCs with increased minimal residual disease, higher relapse rate, and decreased survival rates in these patients. Recently, a number of reports have addressed effective ways to utilize new-generation genomic sequencing and transcriptomic analyses to identify targeted therapeutic agents aimed at LSCs, while sparing normal hematopoietic stem cells. These data underscore the value of timely translation of knowledge from adult studies to the unique molecular and physiological characteristics seen in pediatric leukemia. We aim to summarize this article in the rapidly expanding field of stem cell biology in hematopoietic malignancies, focusing particularly on relevant preclinical models and novel targeted therapeutics, and their applicability to childhood leukemia.

Exosomal MiRNAs in Pediatric Cancers

MicroRNAs (miRNAs) have generated great attention in oncology as they play a fundamental role in the regulation of gene expression and their aberrant expression is present in almost all types of tumors including pediatric ones. The discovery that miRNAs can be transported by exosomes, which are vesicles of 40–120 nm involved in cellular communication, that are produced by different cell types, and that are present in different biological fluids, has opened the possibility of using exosomal miRNAs as biomarkers. The possibility to diagnose and monitor the progression and response to drugs through molecules that can be easily isolated from biological fluids represents a particularly important aspect in the pediatric context where invasive techniques are often used. In recent years, the idea of liquid biopsy as well as studies on the possible role of exosomal miRNAs as biomarkers have developed greatly. In this review, we report an overview of all the evidences acquired in recent years on the identification of exosomal microRNAs with biomarker potential in pediatric cancers. We discuss the following herein: neuroblastoma, hepatoblastoma, sarcomas (osteosarcoma, Ewing’s sarcoma and rhabdoid tumors, and non-rhabdomyosarcoma soft tissue sarcoma), brain tumors, lymphomas, and leukemias.

Socioeconomic status and incidence of pediatric leukemia in Canada: 1992-2010

BACKGROUND

Leukemia is the most common cancer among Canadian children, representing about a third of pediatric cancers in Canada and is responsible for about one-third of pediatric cancer deaths. Understanding the effect of socioeconomic status (SES) on pediatric leukemia incidence provides valuable information for cancer control and interventions in Canada.

METHODS

Using a linked data from the Canadian Cancer Registry (CCR), Canadian Census of Population (CCP) and National Household Survey (NHS) we aimed to quantify socioeconomic inequalities in the incidence of pediatric leukemia from 1992 to 2010. We used the concentration index (C) approach to quantify income- and education-related inequalities in the incidence of pediatric leukemia over time.

RESULTS

Though there were fluctuations in incidence over the study period, our results showed that the total incidence of pediatric leukemia in Canada was generally consistent from 1992 to 2010. Incidence rate of 47 per 1,000,000 as at 1992 rose to 57 per 1,000,000 in 2010. The estimated values of the C over the study period failed to show any significant association between pediatric leukemia incidence and household income or education status.

CONCLUSIONS

Although pediatric leukemia incidence is not rising significantly, it is not reducing significantly either. The incidence of pediatric leukemia showed no significant association with socioeconomic status. Future cancer control interventions should focus more on mitigating risk factors that are independent of socioeconomic status.

Relapse-associated AURKB blunts the glucocorticoid sensitivity of B cell acute lymphoblastic leukemia

Glucocorticoids (GCs) are used in combination chemotherapies as front-line treatment for B cell acute lymphoblastic leukemia (B-ALL). Although effective, many patients relapse and become resistant to chemotherapy and GCs in particular. Why these patients relapse is not clear. We took a comprehensive, functional genomics approach to identify sources of GC resistance. A genome-wide shRNA screen identified the transcriptional coactivators EHMT2, EHMT1, and CBX3 as important contributors to GC-induced cell death. This complex selectively supports GC-induced expression of genes contributing to cell death. A metaanalysis of gene expression data from B-ALL patient specimens revealed that Aurora kinase B (AURKB), which restrains GC signaling by phosphorylating EHMT1-2, is overexpressed in relapsed B-ALL, suggesting it as a potential contributor to relapse. Inhibition of AURKB enhanced GC-induced expression of cell death genes, resulting in potentiation of GC cytotoxicity in cell lines and relapsed B-ALL patient samples. This function for AURKB is distinct from its canonical role in the cell cycle. These results show the utility of functional genomics in understanding mechanisms of resistance and rapidly identifying combination chemotherapeutics.

MiRNA Dysregulation in Childhood Hematological Cancer

For decades, cancer biology focused largely on the protein-encoding genes that have clear roles in tumor development or progression: cell-cycle control, apoptotic evasion, genome instability, drug resistance, or signaling pathways that stimulate growth, angiogenesis, or metastasis. MicroRNAs (miRNAs), however, represent one of the more abundant classes of cell modulators in multicellular organisms and largely contribute to regulating gene expression. Many of the ~2500 miRNAs discovered to date in humans regulate vital biological processes, and their aberrant expression results in pathological and malignant outcomes. In this review, we highlight what has been learned about the roles of miRNAs in some of the most common human pediatric leukemias and lymphomas, along with their value as diagnostic/prognostic factors.

Mometasone furoate inhibits growth of acute leukemia cells in childhood by regulating PI3K signaling pathway

OBJECTIVES

Acute lymphoblastic leukemia (ALL) is the most common cancer before the age of 15 years, seriously endangering the health of children. The main treatment for Childhood ALL was pharmacotherapy. But these drugs have many side effects and some of them could develop drug resistance quickly. Mometasone furoate (MF) is an efficient glucocorticoid for topical treatment of inflammation on the skin, lung and nose.

METHODS

In this study, we investigated whether the MF had effects on ALL cells proliferation and migration.

RESULTS

The CCK-8 proliferation test showed that the cell viability was the lowest at 25 nM MF treatment and the increased OD value was time-dependent. In transwell assay, the number of CCRF-CEM cells was reduced in MF treated group. We found the expression of anti-apoptotic protein bcl-2 decreased the expression of pro-apoptotic protein caspase3 and bax increased in CCRF-CEM cell line treated with MF. The expression of p-AKT, p-mTOR, p70S6 K, vascular endothelial growth factor and CyclinD1 were decreased in MF treated group.

CONCLUSION

This study reveals that MF can inhibit proliferation and invasion/migration and induce apoptosis in Childhood ALL cells, which may be regulated by Phosphatidylinositol 3-kinase signaling pathway. These results suggest MF may be a potential new drug target for clinical ALL treatment.

Protective Mechanism of Hydrogen Sulfide against Chemotherapy-Induced Cardiotoxicity

Over the past few decades, the number of long term survivors of childhood cancers has been increased exponentially. However, among these survivors, treatment-related toxicity, especially cardiotoxicity, is becoming the essential cause of morbidity and mortality. Thus, preventing the treatment-related adverse effects is important to increase the event free survival during the treatment of cancer in children and adolescents. Accumulating evidence has demonstrated that hydrogen sulfide (H₂S) exerts a protective role on cardiomyocytes through a variety of mechanisms. Here, we mainly reviewed the cardioprotective role of H₂S in the chemotherapy, and emphatically discussed the possible mechanisms.

Childhood Leukemia and Primary Prevention

Leukemia is the most common pediatric cancer, affecting 3800 children per year in the United States. Its annual incidence has increased over the last decades, especially among Latinos. Although most children diagnosed with leukemia are now cured, many suffer long-term complications, and primary prevention efforts are urgently needed. The early onset of leukemia-usually before 5 years of age-and the presence at birth of "pre-leukemic" genetic signatures indicate that pre- and postnatal events are critical to the development of the disease. In contrast to most pediatric cancers, there is a growing body of literature-in the United States and internationally-that has implicated several environmental, infectious, and dietary risk factors in the etiology of childhood leukemia, mainly for acute lymphoblastic leukemia, the most common subtype. For example, exposures to pesticides, tobacco smoke, solvents, and traffic emissions have consistently demonstrated positive associations with the risk of developing childhood leukemia. In contrast, intake of vitamins and folate supplementation during the preconception period or pregnancy, breastfeeding, and exposure to routine childhood infections have been shown to reduce the risk of childhood leukemia. Some children may be especially vulnerable to these risk factors, as demonstrated by a disproportionate burden of childhood leukemia in the Latino population of California. The evidence supporting the associations between childhood leukemia and its risk factors-including pooled analyses from around the world and systematic reviews-is strong; however, the dissemination of this knowledge to clinicians has been limited. To protect children's health, it is prudent to initiate programs designed to alter exposure to well-established leukemia risk factors rather than to suspend judgment until no uncertainty remains. Primary prevention programs for childhood leukemia would also result in the significant co-benefits of reductions in other adverse health outcomes that are common in children, such as detriments to neurocognitive development.