Real-world experience of thrombopoietin receptor agonists in pediatric immune thrombocytopenia: a report from a Chinese tertiary children's hospital.

Background: Primary immune thrombocytopenia (ITP) is the most common bleeding disorder in children. There are approximately 20% pediatric ITP patients respond poor to corticosteroids as first-line treatment. Recently thrombopoietin receptor agonists (TPO-RAs) have been used to treat refractory ITP and have achieved certain therapeutic effects. To investigate the efficacy and safety of TPO-RAs in the treatment of pediatric ITP, we conducted this real-world study. Methods: Fifty-three pediatric patients with ITP who did not respond well to corticosteroids were treated with TPO-RAs. Clinical data, including therapeutic response rate, changes in platelet (PLT) count, and adverse events (AEs) were collected. Results: Of the 51 evaluable patients, 37 (72.5%) responded to TPO-RAs. Patients aged >4 years had a higher response rate than those aged ≤4 years (81.1% vs. 50.0%, P=0.04). There was no effect of sex, duration of disease, prior therapy, Mycoplasma pneumoniae (MP) immunoglobulin M (IgM) positivity, antinuclear antibody (ANA) positivity, CD4/CD8 ratio or baseline PLT count on the response rate (P>0.05). Other than 10 patients with PLT counts that exceeded the upper limit of normal, AEs were sporadic, including increased aminotransferase levels, cough, headache, and vomiting. Conclusions: TPO-RAs exhibited good clinical efficacy in pediatric ITP patients who failed to respond to first-line treatment, especially patients aged >4 years, and the side effects were minor.

Risk factors for hemorrhagic cystitis in children undergoing hematopoietic stem cell transplantation: a systematic review and meta-analysis.

BACKGROUND: The risk factors for hemorrhagic cystitis (HC) in children undergoing hematopoietic stem cell transplantation (HSCT) are unclear. Therefore, we conducted this systematic review and meta-analysis to investigate the risk factors for HC in children undergoing HSCT. METHODS: We performed this meta-analysis by retrieving studies from PubMed, EMBASE, and the Cochrane Library up to October 10, 2023, and analyzing those that met the inclusion criteria. I2 statistics were used to evaluate heterogeneity. RESULTS: Twelve studies, including 2,764 patients, were analyzed. Male sex (odds ratio [OR] = 1.52; 95% confidence interval [CI], 1.16-2.00; p = 0.003, I2 = 0%), allogeneic donor (OR = 5.28; 95% CI, 2.60-10.74; p < 0.00001, I2 = 0%), human leukocyte antigen (HLA) mismatched donor (OR = 1.86; 95% CI, 1.00-3.44; p = 0.05, I2 = 31%), unrelated donor (OR = 1.58; 95% CI, 1.10-2.28; p = 0.01, I2 = 1%), myeloablative conditioning (MAC) (OR = 3.17; 95% CI, 1.26-7.97; p = 0.01, I2 = 0%), busulfan (OR = 2.18; 95% CI, 1.33-3.58; p = 0.002, I2 = 0%) or anti-thymoglobulin (OR = 1.65; 95% CI, 1.07-2.54; p = 0.02, I2 = 16%) use, and cytomegalovirus (CMV) reactivation (OR = 2.64; 95% CI, 1.44-4.82; p = 0.002, I2 = 0%) were risk factors for HC in children undergoing HSCT. CONCLUSIONS: Male sex, allogeneic donor, HLA-mismatched, unrelated donor, MAC, use of busulfan or anti-thymoglobulin, and CMV reactivation are risk factors for HC in children undergoing HSCT.

Pediatric acute myeloid leukemia with t(8;21) and KIT mutation treatment with avapritinib post-stem cell transplantation: a report of four cases.

Acute myeloid leukemia (AML) with t(8;21) (q22;q22), which forms RUNX1::RUNX1T1 fusion gene, is classified as a favorable-risk group. However, the presence of mutations in KIT exon 17 results in an adverse prognosis in this group. Avapritinib, a novel tyrosine kinase inhibitor, was designed to target KIT mutation. We report a retrospective study of four pediatric patients with AML with t(8:21) and KIT exon 17 mutation who were treated with avapritinib, three of them failed to demethylate drugs and donor lymphocyte infusion targeting RUNX1::RUNX1T1-positivity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). So far, all patients with RUNX1::RUNX1T1 positivity had turned negative after 1, 9, 7, 2 months of avapritinib treatment. The common adverse effect of avapritinib is neutropenia, which is well-tolerated. This case series indicates that avapritinib may be effective and safe for preemptive treatment of children with AML with t(8;21) and KIT mutation after allo-HSCT, providing a treatment option for preventing relapse after allo-HSCT.

Bernard-Soulier syndrome caused by two novel heterozygous GP1BA gene mutations: a case report and literature review.

BACKGROUND: Bernard-Soulier syndrome (BSS) is a rare inherited macrothrombocytopenia, usually autosomal recessive, which is characterized by prolonged bleeding, thrombocytopenia, and abnormally large platelets. METHODS: For more than 6 years, we misdiagnosed a patient with BSS without an obvious bleeding tendency as having idiopathic thrombocytopenia purpura (ITP), prior to obtaining a genetic analysis. On admission, routine hematology showed a platelet count of 30 × 109/L and mean platelet volume (MPV) of 14.0 fL. RESULTS: Whole-exome sequencing revealed two likely pathogenic heterozygous mutations (c.95_101del and c.1012del) in GP1BA. Flow cytometry analysis of platelet membrane glycoproteins indicated that the expression of GP1b was 0.28% of the normal level. Platelet aggregation tests indicated that platelet aggregation was inhibited by ristocetin- (1.7%), ADP- (14.5%), and arachidonic acid- (5.6%) induced platelet aggregation. A literature review identified reports on 53 mutations in the GP1BA gene in 253 patients, 29 mutations in the GP1BB gene in 90 patients, and 32 mutations in the GP9 gene in 114 patients. CONCLUSION: This case report describes two novel gene mutation sites that have not been reported previously, enriching understanding of the GP1BA mutation spectrum.

Outcome of infants with acute lymphoblastic leukemia treated with the Chinese Children's Cancer Group Acute Lymphoblastic Leukemia 2015 study protocol.

Not available.

Infectious complications in pediatric patients undergoing CD19+CD22+ chimeric antigen receptor T-cell therapy for relapsed/refractory B-lymphoblastic leukemia.

Chimeric antigen receptor T-cell (CAR-T) therapy is effective in the treatment of relapsed/refractory acute B-lymphoblastic leukemia (R/R B-ALL); however, patients who receive CAR-T therapy are predisposed to infections, with considerable detrimental effects on long-term survival rates and the quality of life of patients. This study retrospectively analyzed infectious complications in 79 pediatric patients with R/R B-ALL treated with CAR-T cells at our institution. Overall, 53 patients developed 88 infections. Nine patients experienced nine infections during lymphodepletion chemotherapy, 35 experienced 41 infections during the early phase (days 0-+ 30 after infusion), and 29 experienced 38 infections during the late phase (day + 31-+ 90 after infusion). Pathogens were identified in 31 infections, including 23 bacteria, seven viruses, and one fungus. Four patients were admitted to the intensive care unit for infection and one died. In a univariate analysis, there were ten factors associated with infection, including tumor load, lymphodepleting chemotherapy, neutrophil deficiency and lymphocyte reduction, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), etc. In a multivariate analysis, CRS ≥ grade 3 was identified as a risk factor for infection (hazard ratio = 2.41, 95% confidence interval: 1.08-5.36, P = 0.031). Therefore, actively reducing the CRS grade may decrease the risk of infection and improve the long-term quality of life of these patients.

[Clinical Analysis of Philadelphia Chromosome-Like Acute Lymphoblastic Leukemia in Children].

OBJECTIVE: To explore the clinical characteristics, molecular characteristics, treatment and prognosis of pediatric Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) with a therapeutic target. METHODS: A total of 27 patients of Ph-like ALL with targeted drug target were initially diagnosed in Children's Hospital of Soochow University from December 2017 to June 2021. The data of age, gender, white blood cell (WBC) count at initial diagnosis, genetic characteristics, molecular biological changes, chemotherapy regimen, different targeted drugs were given, and minimal residual disease (MRD) on day 19, MRD on day 46, whether hematopoietic stem cell transplantation (HSCT) were retrospective analyed, and the clinical characteristics and treatment effect were summarized. Survival analysis was performed by Kaplan-Meier method. RESULTS: The intensity of chemotherapy was adjusted according to the MRD level during induced remission therapy in 27 patients, 10 patients were treated with targeted drugs during treatment, and 3 patients were bridged with HSCT, 1 patient died and 2 patients survived. Among the 24 patients who did not receive HSCT, 1 patient developed relapse, and achieved complete remission (CR) after treatment with chimeric antigen receptors T cells (CAR-T). The 3-year overall survival, 3-year relapse-free survival and 3-year event-free survival rate of 27 patients were (95.5±4.4)%, (95.0±4.9)% and (90.7±6.3)% respectively. CONCLUSION: Risk stratification chemotherapy based on MRD monitoring can improve the prognosis of Ph-like ALL in children, combined with targeted drugs can achieve complete remission as soon as possible in children whose chemotherapy response is poor, and sequential CAR-T and HSCT can significantly improve the therapeutic effect of Ph-like ALL in children whose MRD is continuously positive during induced remission therapy.

Super enhancer related gene ANP32B promotes the proliferation of acute myeloid leukemia by enhancing MYC through histone acetylation.

BACKGROUND: Acute myeloid leukemia (AML) is a malignancy of the hematopoietic system, and childhood AML accounts for about 20% of pediatric leukemia. ANP32B, an important nuclear protein associated with proliferation, has been found to regulate hematopoiesis and CML leukemogenesis by inhibiting p53 activity. However, recent study suggests that ANP32B exerts a suppressive effect on B-cell acute lymphoblastic leukemia (ALL) in mice by activating PU.1. Nevertheless, the precise underlying mechanism of ANP32B in AML remains elusive. RESULTS: Super enhancer related gene ANP32B was significantly upregulated in AML patients. The expression of ANP32B exhibited a negative correlation with overall survival. Knocking down ANP32B suppressed the proliferation of AML cell lines MV4-11 and Kasumi-1, along with downregulation of C-MYC expression. Additionally, it led to a significant decrease in H3K27ac levels in AML cell lines. In vivo experiments further demonstrated that ANP32B knockdown effectively inhibited tumor growth. CONCLUSIONS: ANP32B plays a significant role in promoting tumor proliferation in AML. The downregulation of ANP32B induces cell cycle arrest and promotes apoptosis in AML cell lines. Mechanistic analysis suggests that ANP32B may epigenetically regulate the expression of MYC through histone H3K27 acetylation. ANP32B could serve as a prognostic biomarker and potential therapeutic target for AML patients.

Adverse events and efficacy of second-round CAR-T cell therapy in relapsed pediatric B-ALL.

OBJECTIVE: Chimeric antigen receptor (CAR) T-cell therapy has transformed the treatment approach for pediatric patients suffering from relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, there was a paucity of data on the challenges associated with second-round CAR-T therapy in this population. METHODS: Medical records of nine pediatric patients who received second-round CAR-T therapy in a single center from June 2019 to May 2023 were analyzed. Throughout the course of the clinical trial, we evaluated adverse events including CRS, CRES, infections, hematologic toxicity, and organ injury, as well as CAR-T responses. RESULTS: Except for one patient who chose CART therapy due to testicular relapse, the remaining patients had indications for CAR-T therapy due to relapse with bone marrow alone or combined with other site. There were no difference between the transfusion dose of CART1 and CART2. No differences of incidence and grade of CRS was found between the first-round CAR-T therapy (CART1) and second-round CAR-T therapy (CART2). Additionally, we found that the incidence of CRES was higher for CART1(3/9,33.3%) than CART2(1/9,11.1%). Our findings revealed that there were no differences of IL-2, IL-4, IL-6, IL-10, IFN-γ, and TNF-α between CART1 and CART2, but the peak level of IL-17A was significantly higher in patients receiving CART1 compared to those receiving CART2 (p = .011). Early and late infection rates after CART1 were higher than CART2. Based on the dynamic changes of ANC, hemoglobin and platelet, ANC, and platelet were reduced obviously post CART. It seems that the incidences of severe thrombocytopenia and severe anemia were higher in the CART1 group compared to CART2. The MRD-negative CR rates for CART1 and CART2 are 100% and 44.4%, respectively (p = .029). All patients experienced events (relapse, chemotherapy, transplantation, or death) after receiving CART2, including one died, three discharged automatically, and the remaining five patients survived. CONCLUSION: Although the remission rate of CART2 is not as high as the CART1 due to the severity of the disease, its safety regarding CRS, CRES, infections, and organ injury is still excellent. Therefore, CART2 remains a viable option for treating pediatric relapsed B-ALL.

Congenital dyserythropoietic anemia type II in a newborn with a novel compound heterozygous mutation in the SEC23B: a case report and review of the literature.

Congenital dyserythropoietic anemia type II (CDA II) refers to a group of extremely rare heterozygous disorders characterized by ineffective erythropoiesis and morphological abnormalities of erythrocytes and bone marrow erythroblasts. Six types of CDA with differing heterogenous genetic mutations have been identified to date. Due to the genetic and clinical heterogeneity of CDA, accurate diagnosis can be very challenging, especially with the clinical overlap observed between CDA and other dyserythropoietic diseases. A 1-month-old infant girl, born to a non-consanguineous family, presented with severe normocytic anemia that required transfusions every 2 to 3 weeks since birth, as well as jaundice. Whole exome sequencing revealed a novel compound heterozygosity in the SEC23B gene, thus establishing the diagnosis of CDA II. Analysis by multiple bioinformatics tools predicted that the mutant proteins were deleterious. Here, we report a novel variation in SEC23B that extends the mutation spectrum of SEC23B in the diagnosis of CDA II.

[Safety and the Short-Term Efficacy of Venetoclax Combined with Azacitidine Followed by Cladribine in Children with Refractory/Relapsed Acute Myeloid Leukemia].

OBJECTIVE: To investigate the safety and the short-term efficacy of venetoclax combined with azacitidine followed by cladribine (VAC regimen) in children with refractory/ relapsed acute myeloid leukemia (AML). METHODS: The clinical data, treatment outcomes, complications, and blood product consumption of 6 children with refractory/relapsed AML treated with VAC regimen in the Children's Hospital of Soochow University from August 2021 to December 2021 were retrospectively analyzed. RESULTS: Among the 6 children, there were 1 male and 5 females. 5 cases were refractory AML, and 1 case was relapsed AML, which recurred again 16 months after allogeneic hematopoietic stem cell transplantation. 4 children were accompanied by chromosomes or genes that predicted poor prognosis, such as RUNX1, FLT3-ITD, KMT2A exon 2-exon 8 dup, MLL-AF6, 7q-, KMT2A exon 2-exon 10 dup, etc. After received VAC regimen, 4 cases achieved CR+CRi, 1 case achieved PR (only MRD did not relieve, MRD was 0.59%), and 1 case was NR (but the proportion of bone marrow blasts decreased). All 6 patients had grade Ⅳ neutropenia, and 4 patients had grade Ⅳ thrombocytopenia. During the period of neutropenia, none of the 6 children developed symptoms of infection such as fever, cough, and diarrhea. No treatment-related death occurred. CONCLUSION: Venetoclax combined with azacitidine followed by cladribine provides a new treatment option for patients with relapsed/refractory AML who have poor efficacy in early induction remission theragy, showing good efficacy and safety.

Risk factors for BK virus-associated hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation: A systematic review and meta-analysis.

OBJECTIVE AND BACKGROUND: BK virus-associated hemorrhagic cystitis (BKV-HC) is an intractable complication leading to higher mortality and prolonged hospitalization among allogeneic hematopoietic stem cell transplantation (allo-HCT) recipients. Therefore, identifying the potential risk factors of BKV-HC after allo-HCT is crucial to improve prognosis and for early prevention. However, the risk factors for BKV-HC remain debatable. Therefore, we conducted a systematic review and meta-analysis to identify the risk factors for BKV-HC, for early prevention of the occurrence of BKV-HC and to improve the quality of life and prognosis of allo-HCT recipients. METHODS: We searched relevant studies from PubMed, EMBASE, and the Cochrane Library up to February 2023. The odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of all risk factors were calculated to evaluate their effects on the occurrence of BKV-HC. RESULTS: Overall, 11 studies involving 2556 allo-HCT recipients were included in this meta-analysis. All included studies were retrospective and published between 2013 and 2022. We found that male sex (OR = 1.32; 95% CI, 1.07-1.62; p = .009, I2  = 34%), haploidentical donor (OR = 1.84; 95% CI, 1.18-2.87; p = .007, I2  = 23%), myeloablative conditioning (OR = 1.76; 95% CI, 1.36-2.28; p < .0001, I2  = 45%), acute graft versus host disease (aGVHD) (OR = 2.73; 95% CI, 2.02-3.69; p < .0001, I2  = 46%), chronic graft versus host disease (cGVHD) (OR = 1.71; 95% CI, 1.12-2.60; p = .01, I2  = 0%), and cytomegalovirus (CMV) reactivation (OR = 3.13; 95% CI, 1.12-8.78; p = .03, I2  = 79%) were significantly associated with BKV-HC in the univariable analysis. CONCLUSIONS: Our meta-analysis indicated that male sex, haploidentical donor, myeloablative conditioning, aGVHD, cGVHD, and CMV reactivation were potential risk factors for BKV-HC.

The influence of methotrexate-related transporter and metabolizing enzyme gene polymorphisms on peri-engraftment syndrome and graft-versus-host disease after haplo-hematopoietic stem cell transplantation in pediatric patients with malignant hematological diseases.

Background: Methotrexate (MTX), utilized as a graft-versus-host disease (GvHD) prophylactic agent in allogeneic hematopoietic stem cell transplantation (allo-HSCT), has been proven to effectively decrease the occurrence of the peri-engraftment syndrome (Peri-ES) and acute GvHD (aGvHD). Changes in the pharmacodynamics of MTX are closely associated with gene polymorphisms in genes encoding drug-metabolizing enzymes and transporters. Nevertheless, the current studies mainly concentrate on leukemia or autoimmune diseases, and limited studies on allo-HSCT were reported. Methods: Here, we retrospectively assessed the relationship between MTX-related transporter and metabolizing enzyme gene polymorphisms, clinical characteristics, and outcomes in 57 pediatric patients who received haploid HSCT (haplo-HSCT) with malignant tumors at a single center. Results: We discovered all gene polymorphisms were in the Hardy-Weinberg equilibrium in our cohort. We discovered a significant correlation between platelet recovery time and ABCB1 (1236C>T) (p = 0.042). Compared with patients with SLCO1B1 (1865+4846T>C) TT, patients with SLCO1B1 (1865+4846T>C) TC/CC had an increased incidence of Peri-ES (p = 0.030). Based on the multivariate Cox analysis, we discovered that SLCO1B1 (1865+4846T>C) TT genotype was an independent protective factor for Peri-ES morbidity (hazard ratio (HR) = 0.464, p = 0.031), and the dose of mononuclear cells reinfused was significantly correlated with II-IV aGvHD (HR = 2.604, p = 0.039). Conclusion: In summary, our findings prove that the host's genotypes might modify the risk of developing Peri-ES, contribute to a better understanding of the inter-individual difference in efficacy, and facilitate the development of individualized approaches to GvHD prophylaxis.

Super Enhancer Regulatory Gene FYB1 Promotes the Progression of T Cell Acute Lymphoblastic Leukemia by Activating IGLL1.

Background: Arising from T progenitor cells, T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignant tumor, accounting for 15% of childhood ALL and 25% of adult ALL. Composing of putative enhancers in close genomic proximity, super enhancer (SE) is critical for cell identity and the pathogenesis of multiple cancers. Belonging to the cytosolute linker protein group, FYB1 is essential for TCR signaling and extensively studied in terms of tumor pathogenesis and metastasis. Dissecting the role of FYN binding protein 1 (FYB1) in T-ALL holds the potential to improve the treatment outcome and prognosis of T-ALL. Methods: In this study, SEs were explored using public H3K27ac ChIP-seq data derived from T-ALL cell lines, AML cell lines and hematopoietic stem and progenitor cells (HSPCs). Downstream target of FYB1 gene was identified by RNA-seq. Effects of shRNA-mediated downregulation of FYB1 and immunoglobulin lambda-like polypeptide 1 (IGLL1) on self-renewal of T-ALL cells were evaluated in vitro and/or in vivo. Results: As an SE-driven gene, overexpression of FYB1 was observed in T-ALL, according to the Cancer Cell Line Encyclopedia database. In vitro, knocking down FYB1 led to comprised growth and enhanced apoptosis of T-ALL cells. In vivo, downregulation of FYB1 significantly decreased the disease burden by suppressing tumor growth and improved survival rate. Knocking down FYB1 resulted in significantly decreased expression of IGLL1 that was also an SE-driven gene in T-ALL. As a downstream target of FYB1, IGLL1 exerted similar role as FYB1 in inhibiting growth of T-ALL cells. Conclusion: Our results suggested that FYB1 gene played important role in regulating self-renewal of T-ALL cells by activating IGLL1, representing a promising therapeutic target for T-ALL patients.

Short-course blinatumomab for refractory/relapse precursor B acute lymphoblastic leukemia in children.

Objective: To evaluate the clinical efficacy and safety of a short course of blinatumomab in children with refractory or relapsed precursor B-cell acute lymphoblastic leukemia (R/R-BCP-ALL). Methods: The clinical data of 33 R/R BCP-ALL children aged 0-18 years who underwent a short course of blinatumomab (14 days) between August 2021 and November 2022 were retrospectively collected and analyzed. Results: Among 33 patients with BCP-ALL, 26 achieved complete remission (CR), with a total remission rate of 78.8% (26/33). The duration of remission was approximately 14 days. Of the 7 children without CR, 5 were still in remission at 28 days. In 11 patients with refractory disease and 22 with recurrence, the remission rates were 90.9% (10/11) and 72.7% (16/22), respectively. The overall survival (OS) rates of the 26 patients with CR and seven patients without CR were 96.1% and 57.1% (p = 0.002), respectively, and the disease-free survival (DFS) rates were 96.1% and 42.9% (p < 0.001), respectively. Among the 26 patients with CR, 15 underwent bridging hematopoietic stem cell transplantation (HSCT) and 11 did not receive HSCT; with OS rates of 93.3% and 100% (p = 0.40) and DFS rates of 93.3% and 100% (p = 0.400), respectively. The OS for all patients was 87.9% (29/33) and the DFS was 84.8% (28/33). There were 18 cases (54.5%) of cytokine release syndrome (CRS), 2 cases (6.1%) of severe CRS (all grade 3), 1 case (3.0%) of immune effector cell-associated neurotoxicity syndrome (ICANS), 0 cases (0%) of ICANS ≥ grade 3, and no deaths caused by treatment. Conclusions: Short-term follow-up revealed a high R/R BCP-ALL remission rate in children treated with a short course of blinatumomab. The toxicity was low and controllable. No significant short-term survival benefits were observed after bridging HSCT with blinatumomab. In developing countries, a short course of blinatumomab can achieve satisfactory outcomes, while reducing household costs and saving medical resources.

Single-cell transcriptomics reveals multiple chemoresistant properties in leukemic stem and progenitor cells in pediatric AML.

BACKGROUND: Cancer patients can achieve dramatic responses to chemotherapy yet retain resistant tumor cells, which ultimately results in relapse. Although xenograft model studies have identified several cellular and molecular features that are associated with chemoresistance in acute myeloid leukemia (AML), to what extent AML patients exhibit these properties remains largely unknown. RESULTS: We apply single-cell RNA sequencing to paired pre- and post-chemotherapy whole bone marrow samples obtained from 13 pediatric AML patients who had achieved disease remission, and distinguish AML clusters from normal cells based on their unique transcriptomic profiles. Approximately 50% of leukemic stem and progenitor populations actively express leukemia stem cell (LSC) and oxidative phosphorylation (OXPHOS) signatures, respectively. These clusters have a higher chance of tolerating therapy and exhibit an enhanced metabolic program in response to treatment. Interestingly, the transmembrane receptor CD69 is highly expressed in chemoresistant hematopoietic stem cell (HSC)-like populations (named the CD69+ HSC-like subpopulation). Furthermore, overexpression of CD69 results in suppression of the mTOR signaling pathway and promotion of cell quiescence and adhesion in vitro. Finally, the presence of CD69+ HSC-like cells is associated with unfavorable genetic mutations, the persistence of residual tumor cells in chemotherapy, and poor outcomes in independent pediatric and adult public AML cohorts. CONCLUSIONS: Our analysis reveals leukemia stem cell and OXPHOS as two major chemoresistant features in human AML patients. CD69 may serve as a potential biomarker in defining a subpopulation of chemoresistant leukemia stem cells. These findings have important implications for targeting residual chemo-surviving AML cells.

BRD4 PROTAC degrader MZ1 exhibits anti-B-cell acute lymphoblastic leukemia effects via targeting CCND3.

INTRODUCTION: B-cell acute lymphoblastic leukemia (B-ALL) is the most prevalent malignant tumor affecting children. While the majority of B-ALL patients (90%) experience successful recovery, early relapse cases of B-ALL continue to exhibit high mortality rates. MZ1, a novel inhibitor of Bromodomains and extra-terminal (BET) proteins, has demonstrated potent antitumor activity against hematological malignancies. The objective of this study was to examine the role and therapeutic potential of MZ1 in the treatment of B-ALL. METHODS: In order to ascertain the fundamental mechanism of MZ1, a sequence of in vitro assays was conducted on B-ALL cell lines, encompassing Cell Counting Kit 8 (CCK8) assay, Propidium iodide (PI) staining, and Annexin V/PI staining. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to examine protein and mRNA expression levels. Transcriptomic RNA sequencing (RNA-seq) was utilized to screen the target genes of MZ1, and lentiviral transfection was employed to establish stably-expressing/knockdown cell lines. RESULTS: MZ1 has been observed to induce the degradation of Bromodomain Containing 4 (BRD4), Bromodomain Containing 3 (BRD3), and Bromodomain Containing 2 (BRD2) in B-ALL cell strains, leading to inhibited cell growth and induction of cell apoptosis and cycle arrest in vitro. These findings suggest that MZ1 exhibits cytotoxic effects on two distinct molecular subtypes of B-ALL, namely 697 (TCF3/PBX1) and RS4;11 (MLL-AF4) B-ALL cell lines. Additionally, RNA-sequencing analysis revealed that MZ1 significantly downregulated the expression of Cyclin D3 (CCND3) gene in B-ALL cell lines, which in turn promoted cell apoptosis, blocked cell cycle, and caused cell proliferation inhibition. CONCLUSION: Our results suggest that MZ1 has potential anti-B-ALL effects and might be a novel therapeutic target.

LMO2 promotes the development of AML through interaction with transcription co-regulator LDB1.

One of the characteristics of leukemia is that it contains multiple rearrangements of signal transduction genes and overexpression of non-mutant genes, such as transcription factors. As an important regulator of hematopoietic stem cell development and erythropoiesis, LMO2 is considered an effective carcinogenic driver in T cell lines and a marker of poor prognosis in patients with AML with normal karyotype. LDB1 is a key factor in the transformation of thymocytes into T-ALL induced by LMO2, and enhances the stability of carcinogenic related proteins in leukemia. However, the function and mechanism of LMO2 and LDB1 in AML remains unclear. Herein, the LMO2 gene was knocked down to observe its effects on proliferation, survival, and colony formation of NB4, Kasumi-1 and K562 cell lines. Using mass spectrometry and IP experiments, our results showed the presence of LMO2/LDB1 protein complex in AML cell lines, which is consistent with previous studies. Furthermore, in vitro and in vivo experiments revealed that LDB1 is essential for the proliferation and survival of AML cell lines. Analysis of RNA-seq and ChIP-Seq results showed that LDB1 could regulate apoptosis-related genes, including LMO2. In LDB1-deficient AML cell lines, the overexpression of LMO2 partially compensates for the proliferation inhibition. In summary, our findings revealed that LDB1 played an important role in AML as an oncogene, and emphasize the potential importance of the LMO2/LDB1 complex in clinical treatment of patients with AML.

Causes of death and treatment-related mortality in newly diagnosed childhood acute lymphoblastic leukemia treatment with Chinese Children's Cancer Group study ALL-2015.

To investigate the possible risk factors for death at post-treatment in children with acute lymphoblastic leukemia (ALL). A multivariate competing risk analysis was performed to retrospectively analyze the data of children with ALL who died after treatment with CCCG-ALL-2015 in China and to determine the possible risk factors for death at post-treatment in children with ALL. Age at the first diagnosis of ≥10 years; final risk level of high-risk; D19 minimal residual disease (MRD) (≥0.01%) and D46 MRD (≥0.01%); genetic abnormalities, such as KMT2A-rearrangement, c-Myc rearrangement, and PDGFRB rearrangement; and the presence of CNS3 (all P values, <0.05) were identified as independent risk factors, whereas the risk level at the first diagnosis of low-risk (LR) and ETV6::RUNX1 positivity was considered as independent protective factors of death in children with ALL. Among the 471 cases of death, 45 cases were treated with CCCG-ALL-2015 only, and 163 (34.61%) were treatment-related, with 62.42% due to severe infections. 55.83% of treatment-related mortality (TRM) occurred in the early phase of treatment (induction phase). TRM has a significant impact on the overall survival of pediatric patients with ALL. Moreover, the CCCG-ALL-2015 regimen has a better safety profile for treating children with ALL, with rates close to those in developed countries (registration number: ChiCTR-IPR-14005706; date of registration: June 4, 2014).