Aggravated bone density decline following symptomatic osteonecrosis in children with acute lymphoblastic leukemia

Causal relationship between osteoporosis, bone mineral density, and osteonecrosis: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Osteonecrosis (ON) is a debilitating orthopedic condition characterized by bone cell death due to impaired blood supply, leading to structural changes and disability. Osteoporosis (OP), a systemic skeletal disease, results in reduced bone density and quality, making bones fragile and prone to fractures. Although distinct, OP and ON share several risk factors such as corticosteroid use and smoking. This study aims to investigate the causal relationships between OP, bone mineral density (BMD), and ON using a bidirectional two-sample Mendelian randomization (MR) approach.

METHODS

This study utilized genome-wide association study (GWAS) data for OP from the FinnGen database, and BMD data for the lumbar spine and femoral neck from the Genetic Factors for Osteoporosis (GEFOS) consortium. ON data were also obtained from the FinnGen database. All participants were of European descent. Genetic instruments were selected based on genome-wide significance, linkage disequilibrium, and strength (F-statistic). Bidirectional MR analysis was performed using inverse-variance weighted (IVW), MR-Egger regression, and weighted median methods to assess causality. Sensitivity analyses, including Cochran's Q test and MR-PRESSO, were conducted to evaluate heterogeneity and pleiotropy.

RESULTS

MR analysis demonstrated a positive causal effect of OP on ON using the IVW method, with an odds ratio (OR) of 1.223 (95% CI: 1.026-1.459, P = 0.025). The weighted median method also confirmed this result with an OR (95% CI) 1.290 (1.021-1.630), P = 0.033. No significant causal effects were found between BMD (lumbar spine and femoral neck) and ON. Furthermore, ON did not exhibit a causal effect on OP or BMD. Sensitivity analyses confirmed the robustness of the results, showing no evidence of heterogeneity or pleiotropy.

CONCLUSION

This study provides evidence of a unidirectional causal relationship between OP and ON, suggesting that individuals with a genetic predisposition to OP have an increased risk of developing ON. These findings highlight the importance of early OP detection and management to potentially reduce ON incidence. The lack of a significant causal relationship between BMD and ON indicates that factors other than bone density, such as vascular health, may play a crucial role in ON development. Future research should explore these mechanisms further to inform clinical interventions.

ALKBH5 promotes T-cell acute lymphoblastic leukemia growth via m6A-guided epigenetic inhibition of miR-20a-5p

This study investigates the role of ALKBH5-mediated m6A demethylation in T-cell acute lymphoblastic leukemia (T-ALL). T-ALL cell lines (HPB-ALL, MOLT4, Jurkat, CCRF-CEM) and human T cells were analyzed. CCRF-CEM and Jurkat cells were transfected with si-ALKBH5, miR-20a-5p-inhibitor, and pcDNA3.1-DDX5. The expression levels of ALKBH5, miR-20a-5p, and DDX5 in these cells were determined using qRT-PCR and Western blotting. Cell viability, proliferation, colony formation, and apoptosis were assessed using CCK-8, EdU staining, colony formation assay, and flow cytometry. mRNA m6A levels were quantified with an m6A RNA methylation detection reagent, and RNA immunoprecipitation was employed to measure the enrichment of DGCR8 and m6A on the primary transcript pri-miR-20a of miR-20a-5p. Dual-luciferase assay confirmed the binding relationship between miR-20a-5p and DDX5. Results showed that ALKBH5 and DDX5 were upregulated in T-ALL tissues and cells, whereas miR-20a-5p was downregulated. Silencing ALKBH5 inhibited T-ALL cell viability, colony formation, and proliferation, while promoting apoptosis. These effects were reversed by miR-20a-5p inhibition or DDX5 overexpression. ALKBH5 reduced the relative m6A level in T-ALL cells and decreased miR-20a-5p expression by reducing DGCR8 binding to pri-miR-20a-5p. miR-20a-5p suppressed DDX5 transcription. In conclusion, ALKBH5-mediated m6A demethylation decreases DGCR8 binding to pri-miR-20a, thereby repressing miR-20a-5p expression and enhancing DDX5 expression, ultimately inhibiting T-ALL cell apoptosis and promoting proliferation.

Clinical Efficacy and Safety of CD7-Targeted CAR T Cell Therapy for T-cell Malignancies: A Systematic Review and Meta-analysis

OBJECTIVES

Although T-cell malignancies are relatively less prevalent compared to B-cell malignancies, they are highly malignant, and patients usually have poor prognoses. Employing CD7-targeted chimeric antigen receptor (CAR) T cell therapy as a novel immunotherapy to treat malignant T cells faces numerous challenges and is in its early phase. To evaluate this possibility, we aimed to review and meta-analyze the related clinical trials systematically.

METHODS

On October 9, 2023, the online databases of PubMed, Scopus, Embase, and Web of Science were systematically searched for pertinent studies. After completing a two-step title/abstract and full-text screening process, the eligible studies were included.

RESULTS

We observed a pooled overall response rate (ORR) of 100%. Partial response (PR), stringent and/or complete response (sCR/CR), and relapse rate were 6%, 85%, and 18%, respectively. Additionally, the pooled rate of minimal residual disease (MRD) negativity was 85%. The most common grade ≥3 adverse events were related to hematological toxicities, including neutropenia (100%), thrombocytopenia (79%), and anemia (57%). Cytokine release syndrome (CRS) was also a frequent complication with a 100% rate; however, 81% of CRS events were low grades. No grade ≥3 GVHD was reported, and the immune effector cell-associated neurotoxicity syndrome (ICANS grade ≥3) was rare (4%).

CONCLUSION

CD7 is an active and safe target that shows promising results in the treatment of relapsed and/or refractory (r/r) T-cell malignancies.

Bone health in childhood cancer survivors, is there really a problem? Pitfalls of assessment, calculating risk, and suggested surveillance and management for osteonecrosis and low and very low bone mineral density

Childhood cancer survivors are at increased risk of developing (long-term) skeletal adverse effects, such as osteonecrosis, impaired bone mineral density, and fractures. This paper provides an overview of the current understanding of bone health in these survivors, examining whether it represents a significant concern. It focusses on the challenges of assessing and managing bone health in childhood cancer survivors, highlighting diagnostic pitfalls, methods for accurately identifying those at high risk, and suggested strategies for the surveillance and management of osteonecrosis and impaired bone mineral density. The need for improved surveillance strategies, particularly for high-risk survivors, alongside potential prevention and management options, including pharmacological and lifestyle interventions, is emphasised. Given the lack of consensus on optimal prevention and treatment strategies, the paper emphasises the need for further research to optimise care and improve long-term outcomes for childhood cancer survivors with bone health impairments.

Bisphosphonate treatment for skeletal complications in paediatric cancer-Experience from a single tertiary centre

AIMS

The aim was to analyse the use and safety of bisphosphonate treatment for metabolic bone complications in paediatric cancer patients.

METHODS

We retrospectively describe our experience with bisphosphonate treatment in 25 childhood cancer patients (aged <18 years) in a single tertiary hospital between 1999 and 2020.

RESULTS

The most common primary diagnosis was acute lymphoblastic leukaemia (n = 16) and Hodgkin lymphoma (n = 3). Eleven patients (44%) had received allogeneic stem cell transplantation and two patients autologous stem cell transplantation. Sixteen patients (64%) had been treated with radiotherapy, either total-body (n = 11) or local (n = 5). The main indication for bisphosphonates was osteoporosis with vertebral compression fractures in 13/25, osteonecrosis in 6/25 and hypercalcaemia in 2/25. The bisphosphonate treatment was started on average 13 (range 0-76) months after the diagnosis of the bone complication. Bisphosphonate treatment lasted between weeks (hypercalcaemia) to 5 years (severe osteoporosis). Mild, non-symptomatic hypophosphatemia (n = 8), hypocalcaemia (n = 6) and moderate, transient pain (n = 6) were the most common adverse effects. No severe side effects were observed even when bisphosphonates were administered concomitantly with chemotherapy. Bone mineral density significantly improved with the bisphosphonate treatment (mean lumbar spine Z-score -1.17 vs. -0.07, p < 0.001).

CONCLUSION

Bisphosphonate treatment was well tolerated in this paediatric patient cohort.

Reductions in Bone Mineral Density Are Apparent Early in Children With Prevalent Osteonecrosis Lesions Following Leukemia Therapy

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multisite magnetic resonance imaging (MRI) more than 1 year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the Steroid Associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1 ± 1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (35%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09 ± 1.53 versus -1.27 ± 1.25, p = 0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31 ± 1.02) but not in those without (0.13 ± 0.82, p = 0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77 ± 1.22) compared to those without (-1.03 ± 1.07, p = 0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98 ± 0.95 versus -0.28 ± 1.06, p = 0.010; TB -1.36 ± 1.10 versus -0.48 ± 1.50, p = 0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p = 0.841. In multivariable models, older age at diagnosis (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.15-2.13; p = 0.004), and hip BMD Z-score at MRI (OR 2.23; 95% CI, 1.02-4.87; p = 0.046) were independently associated with ON. Overall, one-third of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first 1 and 2 years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Clinical features, laboratory characteristics, and outcome of ETP and TCRA/D aberrations in pediatric patients with T-acute lymphoblastic leukemia

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy with few accepted prognostic factors that limit the efficiency of therapy. The aim of the current study was to assess the clinical and laboratory features of T-cell receptor (TCR) aberrations and early T-cell precursor (ETP) subtype as well as their outcome to therapy.

METHODS

Sixty-three newly diagnosed pediatric T-ALL patients were assessed for the ETP status using immunophenotyping. Screening of TCRA/D aberrations was done by fluorescent in situ hybridization (FISH). The data were correlated to the patients' clinical features, response to treatment, and survival rates.

RESULTS

Seven patients (11%) had ETP-ALL. The ETP-ALL patients were older (P = 0.013), presented with lower white blood cell (WBC) count (P = 0.001) and lower percentage of peripheral blood (PB) blast cells (P = 0.037), more likely to have hyperdiploid karyotype (P = 0.009), and had been associated with TCRA/D gene amplification (P = 0.014) compared to other T-ALL patients. Of note, the same associations had been significantly observed in patients with TCRA/D gene amplification. Patients with TCRA/D amplification frequently coincided with TCRβ aberrations (P = 0.025). TCR-β aberrations were significantly associated with negative MRD at the end of induction compared to TCR-β-negative patients. There was a nonsignificant trend of ETP-positive cases to have lower overall survival (OS) (P = 0.06). Patients with TCR aberrations had no significant differences regarding disease-free survival (DFS) or OS rates compared to those with normal TCR.

CONCLUSION

ETP-ALL patients tend to have increased mortalities. There was no significant impact of TCR aberrations on the survival rates of the patients.

Orthopaedic adverse events among adolescents and adults treated with asparaginase for acute lymphoblastic leukaemia

Osteonecrosis (ON) is a complication of acute lymphoblastic leukaemia (ALL) treatment with patient- (age, female sex, genetic polymorphisms, presence of metabolic syndrome) and treatment-specific (glucocorticoid type and schedule) risk factors described. The potential role of asparaginase in increasing risk of ON via effects on coagulation, lipid metabolism, and steroid clearance is now also recognised. Paediatric studies consistently identify age as a key risk factor for ON, with adolescents at higher risk than young children. Fewer studies comprehensively report on risk of ON in adults, but available evidence suggests that adolescents and young adults (AYAs) treated with corticosteroid and asparaginase-containing paediatric-inspired regimens are more at risk than older adults treated with paediatric-inspired or traditional adult regimens. There are few proven strategies to prevent or mitigate the severity of ON and other orthopaedic complications of ALL therapy. Future clinical trials should carefully ascertain orthopaedic adverse events in adults. Evidence-based guidelines should be developed for management of orthopaedic adverse events in adults being treated for ALL, especially high-risk AYAs being treated with paediatric-inspired regimens.

Animal models of acute lymphoblastic leukemia: Recapitulating the human disease to evaluate drug efficacy and discover therapeutic targets

Acute lymphoblastic leukemia (ALL) is a malignant hematologic tumor with highly aggressive characteristics, which is prone to relapse, has a poor prognosis and few clinically effective drugs. It is meaningful to gain a better understanding of its pathogenesis in order to discover and evaluate potential therapeutic drugs and new treatment targets. The goal of developing novel targeted drugs and treatment methods is to increase complete remission, reduce toxicity and morbidity, and that is also the most important prerequisite for modern leukemia treatment. However, the process of new drugs from research and development to clinical application is long and difficult. Many promising drugs were rejected by the USFoodandDrugAdministration(FDA) due to serious adverse drug reactions (ADR) in clinical phase I trials. Animal models provide us with an excellent tool to understand the complex pathological mechanisms of human diseases, to evaluate the potential of new targeted drugs and therapeutic approaches to treat ALL in vivo and, more importantly, to assess the potential ADR they may have on healthy organs. In this article we review ALL animal models' progression, their roles in revealing the pathogenesis of ALL and drug development. Additionally, we mainly focus on the mouse models, especially xenotransplantation and transgenic models that more closely reproduce the human phenotype. In conclusion, we summarize the advantages and limitations of each model, thereby facilitating further understanding the etiology of ALL, and eventually contributing to the effective management of the disease.

A Validated Risk Prediction Model for Bone Fragility in Children With Acute Lymphoblastic Leukemia

Although bone fragility may already be present at diagnosis of pediatric acute lymphoblastic leukemia (ALL), routine performance of dual-energy X-ray absorptiometry (DXA) in every child is not universally feasible. The aim of this study was to develop and validate a risk prediction model for low lumbar spine bone mineral density (LS BMD Z-score ≤ -2.0) at diagnosis, as an important indicator for fracture risk and further treatment-related BMD aggravation. Children with ALL (4-18 years), treated according to the Dutch Childhood Oncology Group protocol (DCOG-ALL9; model development; n = 249) and children from the Canadian Steroid-Associated Osteoporosis in the Pediatric Population cohort (STOPP; validation; n = 99) were included in this study. Multivariable logistic regression analyses were used to develop the prediction model and to confirm the association of low LS BMD at diagnosis with symptomatic fractures during and shortly after cessation of ALL treatment. The area under the receiver operating characteristic curve (AUC) was used to assess model performance. The prediction model for low LS BMD at diagnosis using weight (β = -0.70) and age (β = -0.10) at diagnosis revealed an AUC of 0.71 (95% CI, 0.63-0.78) in DCOG-ALL9 and 0.74 (95% CI, 0.63-0.84) in STOPP, and resulted in correct identification of 71% of the patients with low LS BMD. We confirmed that low LS BMD at diagnosis is associated with LS BMD at treatment cessation (OR 5.9; 95% CI, 3.2-10.9) and with symptomatic fractures (OR 1.7; 95% CI, 1.3-2.4) that occurred between diagnosis and 12 months following treatment cessation. In meta-analysis, LS BMD at diagnosis (OR 1.6; 95% CI, 1.1-2.4) and the 6-month cumulative glucocorticoid dose (OR 1.9; 95% CI, 1.1-3.2) were associated with fractures that occurred in the first year of treatment. In summary, a prediction model for identifying pediatric ALL patients with low LS BMD at diagnosis, as an important indicator for bone fragility, was successfully developed and validated. This can facilitate identification of future bone fragility in individual pediatric ALL patients. © 2021 American Society for Bone and Mineral Research (ASBMR).

Combination therapy with miR-34a and doxorubicin synergistically induced apoptosis in T-cell acute lymphoblastic leukemia cell line

MicroRNAs are identified to take actively part in the development of different cancers. Reduced expression of tumor suppressor miRNAs leads to cancer cell development, so restoring the expression of these miRNAs can be an appropriate treatment option for cancer. Due to the heterogeneity of cancer cells, single-drug therapy often results in drug resistance. Therefore, the combination of chemotherapy with miRNA can be a powerful strategy for cancer treatment. In the current investigation, miR-34a mimic, and negative control were purchased and transfected using jetPEI reagents. Then the synergic effects of miR-34a in combination with doxorubicin were investigated on cell death of acute T-cell lymphoblastic leukemia Jurkat cell line, as well as the expression of some genes including Caspase-3, Bcl-2, and p53 which are involved in apoptosis. Our outcomes showed that this combination remarkably reduced the expression of the Bcl-2 gene, the target gene of miR-34a. According to the results of the MTT assay, the survival rate was significantly decreased compared to the untreated cells. Results of the flow cytometry assay and DAPI staining demonstrated an increased apoptosis rate of Jurkat cells in combination therapy. Moreover, cell cycle arrest was observed at the G2/M phase in cells that were treated with miR-34a/doxorubicin. Most importantly, we showed that the transfection of the Jurkat cells with miR-34a increased the sensitivity of these cells to doxorubicin. Furthermore, the combination of miR-34a and doxorubicin drug effectively increased apoptosis of treated cells. Therefore, this method can be used as an impressive treatment for T-ALL.

Recent perspectives on the association between osteonecrosis and bone mineral density decline in childhood acute lymphoblastic leukemia

The attention to treatment-related toxicity has increased since the survival of children with acute lymphoblastic leukemia (ALL) has improved significantly over the past few decades. Intensive ALL treatment schedules including corticosteroids and asparaginase have been shown to give rise to skeletal abnormalities such as osteonecrosis and low bone mineral density (BMD), which may lead to debilitating sequelae in survivors. Although osteonecrosis and low BMD are different entities with suggested separate pathophysiological mechanisms, recent studies indicate that osteonecrosis is associated with accelerated BMD decline. Common underlying mechanisms for osteonecrosis and BMD decline are considered, such as an enhanced sensitivity to corticosteroids in children who suffer from both osteonecrosis and low BMD. In addition, restriction of weight-bearing activities, which is generally advised in patients with osteonecrosis, could aggravate BMD decline. This induces a clinical dilemma, since bone stimulation is important to maintain BMD but alternative interventions for osteonecrosis are limited. Furthermore, this recent finding of accelerated BMD decline in children with osteonecrosis emphasizes the need to develop effective preventive measures for osteonecrosis, which may include targeting BMD decline.

Osteonecrosis in Adults With Acute Lymphoblastic Leukemia: An Unmet Clinical Need

Osteonecrosis is a serious complication of antileukemic therapy associated with severe pain and reduced mobility, ultimately leading to joint destruction and significant long-term morbidity. The 5-year cumulative incidence of osteonecrosis ranges from 11% to 20% in adolescents and young adults to 3% to 8% in patients aged 30 years and older. Most symptomatic patients have multiple joints affected, which in turn poses a risk factor for developing severe osteonecrosis. Osteonecrosis has a multifactorial genesis. Treatment-associated risk factors for developing osteonecrosis depend on the therapeutic context including the use of glucocorticosteroids and the simultaneous and/or intensified use of asparaginase (ASP) which may, among others, exert its effect on blood supply to the bone through hypertriglyceridemia, hypercholesterolemia, and hypertension. Allogeneic hematopoietic stem cell transplantation, bloodstream infections, and genetic factors may additionally impact the risk of osteonecrosis. In this article, the authors used the best available evidence in the literature to develop management recommendations for the use in the context of steroid and asparaginase containing regimens. These considerations may be helpful for similar treatment approaches.

[β-arrestin1 overexpression suppresses progression of human T-cell acute lymphatic leukemia Molt-4 cell xenograft in mice]

OBJECTIVE

To investigate the effect of β-arrestin1 overexpression on tumor progression in a NCG mouse model bearing T-cell acute lymphocytic leukemia (T-ALL) Molt-4 cell xenograft.

METHODS

Molt-4 cells were tagged with firefly-luciferase (F-Luc) by lentiviral infection, and fluorescence intensity of the cells was detected using a luminescence detector. Molt-4 cell lines with β-arrestin1 overexpression or knockdown were constructed by lentivirus infection and injected via the tail vein in sub-lethal irradiated NCG mice. Body weight changes and survival time of the xenografted mice were observed, and the progression of T-ALL in the mice was evaluated using an in vivo fluorescence imaging system. Sixteen days after xenografting, the mice were euthanatized and tumor cell infiltration was observed in the slices of the liver and spleen.

RESULTS

We successfully tagged Molt-4 cells with F-Luc and overexpressed or knocked down β-arrestin1 in the tagged cells. Bioluminescent imaging showed obvious luminescence catalyzed by F-Luc in Molt-4 cells. After injection of Molt-4-Luc cells into irradiated NCG mice, a gradual enhancement of luminescence in the xenografted mice was observed over time, while the body weight of the mice decreased. Compared with the control mice, the mice xenografted with β-arrestin1-overexpressing Molt-4 cells had significantly prolonged survival time (P < 0.001), while the survival time of the mice xenografted with Molt-4 cells with β- arrestin1 knockdown was significantly shortened (P < 0.001). Histological examination revealed fewer infiltrating tumor cells in the liver and spleen of the mice xenografted with β-arrestin1-overexpressing Molt-4 cells in comparison with the mice bearing parental Molt-4 cell xenografts.

CONCLUSIONS

β-arrestin1 overexpression suppresses tumor progression in mice bearing Molt-4 cell xenograft.

Comparing osteonecrosis clinical phenotype, timing, and risk factors in children and young adults treated for acute lymphoblastic leukemia

BACKGROUND

Treatment-related osteonecrosis (ON) is a serious complication of treatment of acute lymphoblastic leukemia (ALL).

PROCEDURE

This study included 1,489 patients with ALL, aged 1-45 years, treated according to the Nordic Society of Paediatric Haematology and Oncology ALL2008 protocol, using alternate-week dexamethasone during delayed intensification, with prospective registration of symptomatic ON. We aimed at comparing risk factors, timing, and clinical characteristics of ON in children and young adults.

RESULTS

ON was diagnosed in 67 patients, yielding a 5-year cumulative incidence of 6.3%, but 28% in female adolescents. Median age at ALL diagnosis was 12.1 years and 14.9 years for females and males, respectively. At ON diagnosis, 59 patients had bone pain (91%) and 30 (46%) had multiple-joint involvement. The median interval between ALL and ON diagnosis was significantly shorter in children aged 1.0-9.9 years (0.7 years [range: 0.2-2.1]) compared with adolescents (1.8 years [range: 0.3-3.7, P < 0.001]) and adults (2.1 years [range: 0.4-5.3, P = 0.001]). Female sex was a risk factor in adolescent patients (hazard ratio [HR] = 2.1, 95% confidence interval [CI]: 1.1-4.2) but not in children aged 1.1-9.9 years (HR = 2.4, 95% CI: 0.9-6.2, P = 0.08) or adults aged 19-45 years (HR = 1.1, 95% CI: 0.3-4.0). Age above 10 years at ALL diagnosis (odds ratio [OR] = 3.7, P = 0.026) and multiple joints affected at ON diagnosis (OR = 3.4, P = 0.027) were risk factors for developing severe ON.

CONCLUSION

We provide a detailed phenotype of patients with ALL with symptomatic ON, including description of risk factors and timing of ON across age groups. This awareness is essential in exploring measures to prevent development of ON.

Development and feasibility of Mandarin-language bone health scales for adolescents with cancer in Taiwan

Cancer during adolescence increases the risk for bone mass deficiency later in life. Adolescents with cancer must learn to improve their bone health to avoid osteoporosis. In the present cross-sectional study, we developed and tested scales to assess the bone health self-efficacy and beliefs of adolescents with cancer in Taiwan. Test development followed three stages: item generation and scale formatting, examination of content validity, and validation of psychometric properties with a sample of 100 adolescents with cancer. Through the validation process, this research generated the seven-item Bone Health Self-Efficacy Scale and the 13-item Bone Health Belief Scale. Multiple indices demonstrated construct validity. Cronbach's alphas (0.809 and 0.705) demonstrated internal consistency. No items caused a drop in Cronbach's alpha of 10%, all inter-item correlations were <0.800, and the factor loadings for all items reached 0.400, demonstrating item appropriateness. The present study provides initial evidence of the scales' accessibility and feasibility for adolescents with cancer who speak Mandarin. These scales might also help clinical nurses evaluate the effectiveness of bone health education provided to adolescents with cancer.

MicroRNA expression and activity in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a lymphoid malignancy caused by the oncogenic transformation of immature T-cell progenitors. Many biologically relevant genetic and epigenetic alterations have been identified as driving factors for this transformation. Recently, microRNAs (miRNAs) have been shown to influence various leukemias, including T-ALL. Aberrant expression of miRNAs can function as either oncogenes or tumor suppressors in T-ALL through the regulation of cell migration, invasion, proliferation, apoptosis, and chemoresistance. This occurs by targeting key signaling pathways or transcriptional factors that play a critical role in T-ALL pathology and progression. Different miRNA expression profiles have been linked to specific genetic subtypes of human T-ALL. Furthermore, miRNAs can also act as independent prognostic factors to predict clinical outcomes for T-ALL patients. In the current review, we will focus on the role of miRNAs in the development and progression of T-ALL.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.

The genetics and molecular biology of T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy caused by the accumulation of genomic lesions that affect the development of T cells. For many years, it has been established that deregulated expression of transcription factors, impairment of the CDKN2A/2B cell-cycle regulators, and hyperactive NOTCH1 signaling play prominent roles in the pathogenesis of this leukemia. In the past decade, systematic screening of T-ALL genomes by high-resolution copy-number arrays and next-generation sequencing technologies has revealed that T-cell progenitors accumulate additional mutations affecting JAK/STAT signaling, protein translation, and epigenetic control, providing novel attractive targets for therapy. In this review, we provide an update on our knowledge of T-ALL pathogenesis, the opportunities for the introduction of targeted therapy, and the challenges that are still ahead.

Osteonecrosis in children with acute lymphoblastic leukemia

The morbidity and toxicity associated with current intensive treatment protocols for acute lymphoblastic leukemia in childhood become even more important as the vast majority of children can be cured and become long-term survivors. Osteonecrosis is one of the most common therapy-related and debilitating side effects of anti-leukemic treatment and can adversely affect long-term quality of life. Incidence and risk factors vary substantially between study groups and therapeutic regimens. We therefore analyzed 22 clinical trials of childhood acute lymphoblastic leukemia in terms of osteonecrosis incidence and risk factors. Adolescent age is the most significant risk factor, with patients >10 years old at the highest risk. Uncritical modification or even significant reduction of glucocorticoid dosage cannot be recommended at this stage. A novel and innovative approach to reduce osteonecrosis-associated morbidity might be systematic early screening for osteonecrosis by serial magnetic resonance images. However, discriminating patients at risk of functional impairment and debilitating progressive joint disease from asymptomatic patients still remains challenging.

Genetic Biomarkers to Identify the Risk of Osteonecrosis in Children with Acute Lymphoblastic Leukemia

Osteonecrosis is a disabling complication of treatment for pediatric acute lymphoblastic leukemia, and much effort has been made to predict which patients are prone to develop this disease. Multiple clinical and genetic factors have already been identified as being associated with osteonecrosis; however, a prediction model that combines pretreatment genetic biomarkers and clinical factors has not yet been designed. Such a prediction model can only be developed with continuing international collaborations and research efforts, including large genome-wide association studies.