Objective:To summarize the clinical characteristics and key points of diagnosis and treatment in children with TCF3::HLF fusion gene-positive acute lymphoblastic leukemia (ALL).Methods:A case series study was conducted. Clinical data of 8 children diagnosed with TCF3::HLF positive ALL at the Hematology Center of Beijing Children′s Hospital, Capital Medical University and the Hematology Oncology Department of Henan Children′s Hospital between January 2019 and January 2024 were collected. Descriptive analysis was performed on their clinical features, laboratory findings, treatment regimens and prognosis.Results:The cohort included 8 children (3 males and 5 females) with the age of 5.5 (3.5, 7.0) years. Bone pain was the primary clinical manifestation in 4 cases, with multi-site skeletal involvement in 4 cases, hypercalcemia in 5 cases, and coagulation abnormalities in 6 cases. Immunophenotyping revealed common B-cell lineage with myeloid markers in 7 cases and common B-cell phenotype in 1 case. All 8 children were positive for the TCF3::HLF fusion gene. Regarding treatment, 1 case abandoned therapy after diagnosis, while the remaining 7 cases received chemotherapy following the Chinese Children′s Leukemia Group-ALL2018 high-risk protocol. Only 1 case achieved minimal residual disease (MRD) negativity by day 33 of induction therapy. Among the 3 cases with MRD negativity before consolidation therapy, 1 case achieved it via conventional chemotherapy, while 2 cases required additional agents (venetoclax or blinatumomab). One case failed to achieve MRD negativity after consolidation therapy and later discontinued treatment (survival periods: 7months).Of the 4 cases who achieved MRD negativity after consolidation, 2 cases received conventional chemotherapy and 2 cases achieved negativity following chimeric antigen receptor T-cell therapy (CART). All 4 cases underwent hematopoietic stem cell transplantation (HSCT). Two cases in the CART combined with HSCT group survived as of the last follow-up (survival periods: 22 and 13 months). In the conventional chemotherapy combined HSCT group, 1 case relapsed and died (survival: 38 months), and 1 case died from transplant complications (survival: 11 months). The other 2 cases achieved MRD negativity before consolidation therapy but did not receive regular subsequent chemotherapy. After MRD recurrence, they underwent CART therapy without HSCT and remained alive at the last follow-up (survival periods: 49 and 12 months).Conclusions:Children with TCF3::HLF positive ALL often present with bone destruction accompanied by hypercalcemia and coagulopathy at initial diagnosis. This subtype of ALL shows poor response to conventional chemotherapy regimens, characterized by low early remission rates and high relapse risk even after HSCT. Better therapeutic outcomes have been observed with small molecule targeted drugs, immunotherapy and CART therapy.

Objective:To investigate the clinical significance of monitoring SIL::TAL1 fusion transcripts in the evaluation of treatment response and prognosis of children with T-acute lymphoblastic leukemia (T-ALL).Methods:A retrospective cohort study was conducted to analyze the clinical data of 46 newly diagnosed pediatric T-ALL with SIL::TAL1 fusion transcripts treated at Beijing Children′s Hospital Capital Medical University from November 2004 to December 2022. The SIL::TAL1 fusion transcripts were quantitatively detected at the initial diagnosis (TP0) and early stage of induction therapy (TP1), at the end of induction remission therapy (TP2), before consolidation therapy (TP3) and subsequent treatment. Patients were divided into negative and positive groups on SIL::TAL1 fusion transcripts level, differences of clinical features and survival among groups at TP0 to TP3 were analyzed. The χ2 test or Fisher exact test or Mann-Whitney U test was used to compare the clinical difference. Survival analysis was estimated by Kaplan-Meier method with Log-Rank testing. Multivariate analysis was conducted by Cox proportional hazards models. Results:Among the 46 children with SIL::TAL1 fusion transcripts, 36 were males and 10 were females, with the onset age of 6.8 (3.4, 9.5) years. The negative rates of SIL::TAL1 fusion transcripts for TP1,TP2, TP3, before delayed intensification Ⅰ treatment (TP4), before maintenance therapy (TP5) were 36% (13/36), 78% (32/41), 76% (32/42), 15/16, and 12/12, respectively. No significant difference was found on clinical features and prednisone response between groups at TP0-TP3 (all P>0.05). The 5-year events free survival (EFS) rate of patients classified as negative (32 cases) and positive (9 cases) groups at TP2 was (78±8)% and (33±16)%, respectively ( χ2=9.86, P=0.002), the 5-year overall survival (OS) rate was (81±7)% and (44±17)%, respectively ( χ2=6.40, P=0.011). The 5-year EFS rate of patients classified as negative (32 cases) and positive (10 cases) groups at TP3 was (78±8)% and (30±15)%, respectively ( χ2=13.04, P<0.001) and the 5-year OS rate was (84±6)% and (30±15)%, respectively ( χ2=15.95, P<0.001). Cox multivariate regression showed that positive of SIL::TAL1 transcript at TP3 was adverse independent prognostic factors for EFS and OS (EFS: HR=6.70, 95% CI 2.01-22.35, P=0.002; OS: HR=10.73, 95% CI 2.50-46.09, P=0.001). Conclusions:Monitoring SIL::TAL1 fusion transcripts can reflect the clinical treatment response. The level of SIL::TAL1 fusion transcripts at early period can predict long-term outcomes of these patients.

Objective:To summarize the clinical characteristics and key points of diagnosis and treatment in children with TCF3::HLF fusion gene-positive acute lymphoblastic leukemia (ALL).Methods:A case series study was conducted. Clinical data of 8 children diagnosed with TCF3::HLF positive ALL at the Hematology Center of Beijing Children′s Hospital, Capital Medical University and the Hematology Oncology Department of Henan Children′s Hospital between January 2019 and January 2024 were collected. Descriptive analysis was performed on their clinical features, laboratory findings, treatment regimens and prognosis.Results:The cohort included 8 children (3 males and 5 females) with the age of 5.5 (3.5, 7.0) years. Bone pain was the primary clinical manifestation in 4 cases, with multi-site skeletal involvement in 4 cases, hypercalcemia in 5 cases, and coagulation abnormalities in 6 cases. Immunophenotyping revealed common B-cell lineage with myeloid markers in 7 cases and common B-cell phenotype in 1 case. All 8 children were positive for the TCF3::HLF fusion gene. Regarding treatment, 1 case abandoned therapy after diagnosis, while the remaining 7 cases received chemotherapy following the Chinese Children′s Leukemia Group-ALL2018 high-risk protocol. Only 1 case achieved minimal residual disease (MRD) negativity by day 33 of induction therapy. Among the 3 cases with MRD negativity before consolidation therapy, 1 case achieved it via conventional chemotherapy, while 2 cases required additional agents (venetoclax or blinatumomab). One case failed to achieve MRD negativity after consolidation therapy and later discontinued treatment (survival periods: 7months).Of the 4 cases who achieved MRD negativity after consolidation, 2 cases received conventional chemotherapy and 2 cases achieved negativity following chimeric antigen receptor T-cell therapy (CART). All 4 cases underwent hematopoietic stem cell transplantation (HSCT). Two cases in the CART combined with HSCT group survived as of the last follow-up (survival periods: 22 and 13 months). In the conventional chemotherapy combined HSCT group, 1 case relapsed and died (survival: 38 months), and 1 case died from transplant complications (survival: 11 months). The other 2 cases achieved MRD negativity before consolidation therapy but did not receive regular subsequent chemotherapy. After MRD recurrence, they underwent CART therapy without HSCT and remained alive at the last follow-up (survival periods: 49 and 12 months).Conclusions:Children with TCF3::HLF positive ALL often present with bone destruction accompanied by hypercalcemia and coagulopathy at initial diagnosis. This subtype of ALL shows poor response to conventional chemotherapy regimens, characterized by low early remission rates and high relapse risk even after HSCT. Better therapeutic outcomes have been observed with small molecule targeted drugs, immunotherapy and CART therapy.

Objective:To investigate the clinical significance of monitoring SIL::TAL1 fusion transcripts in the evaluation of treatment response and prognosis of children with T-acute lymphoblastic leukemia (T-ALL).Methods:A retrospective cohort study was conducted to analyze the clinical data of 46 newly diagnosed pediatric T-ALL with SIL::TAL1 fusion transcripts treated at Beijing Children′s Hospital Capital Medical University from November 2004 to December 2022. The SIL::TAL1 fusion transcripts were quantitatively detected at the initial diagnosis (TP0) and early stage of induction therapy (TP1), at the end of induction remission therapy (TP2), before consolidation therapy (TP3) and subsequent treatment. Patients were divided into negative and positive groups on SIL::TAL1 fusion transcripts level, differences of clinical features and survival among groups at TP0 to TP3 were analyzed. The χ2 test or Fisher exact test or Mann-Whitney U test was used to compare the clinical difference. Survival analysis was estimated by Kaplan-Meier method with Log-Rank testing. Multivariate analysis was conducted by Cox proportional hazards models. Results:Among the 46 children with SIL::TAL1 fusion transcripts, 36 were males and 10 were females, with the onset age of 6.8 (3.4, 9.5) years. The negative rates of SIL::TAL1 fusion transcripts for TP1,TP2, TP3, before delayed intensification Ⅰ treatment (TP4), before maintenance therapy (TP5) were 36% (13/36), 78% (32/41), 76% (32/42), 15/16, and 12/12, respectively. No significant difference was found on clinical features and prednisone response between groups at TP0-TP3 (all P>0.05). The 5-year events free survival (EFS) rate of patients classified as negative (32 cases) and positive (9 cases) groups at TP2 was (78±8)% and (33±16)%, respectively ( χ2=9.86, P=0.002), the 5-year overall survival (OS) rate was (81±7)% and (44±17)%, respectively ( χ2=6.40, P=0.011). The 5-year EFS rate of patients classified as negative (32 cases) and positive (10 cases) groups at TP3 was (78±8)% and (30±15)%, respectively ( χ2=13.04, P<0.001) and the 5-year OS rate was (84±6)% and (30±15)%, respectively ( χ2=15.95, P<0.001). Cox multivariate regression showed that positive of SIL::TAL1 transcript at TP3 was adverse independent prognostic factors for EFS and OS (EFS: HR=6.70, 95% CI 2.01-22.35, P=0.002; OS: HR=10.73, 95% CI 2.50-46.09, P=0.001). Conclusions:Monitoring SIL::TAL1 fusion transcripts can reflect the clinical treatment response. The level of SIL::TAL1 fusion transcripts at early period can predict long-term outcomes of these patients.

Objective:To analyze the clinical characteristics and prognosis of patients with infant acute lymphoblastic leukemia (IALL).Methods:A retrospective cohort study.Clinical data, treatment and prognosis of 28 cases of IALL who have been treated at Beijing Children′s Hospital, Capital Medical University and Baoding Children′s Hospital from October 2013 to May 2023 were analyzed retrospectively. Based on the results of fluorescence in situ hybridization (FISH), all patients were divided into KMT2A gene rearrangement (KMT2A-R) positive group and KMT2A-R negative group. The prognosis of two groups were compared. Kaplan-Meier method and Log-Rank test were used to analyze the survival of the patients.Results:Among 28 cases of IALL, there were 10 males and 18 females, with the onset age of 10.9 (9.4,11.8) months. In terms of immune classification, 25 cases were B-ALL (89%), while the remaining 3 cases were T-ALL (11%). Most infant B-ALL showed pro-B lymphocyte phenotype (16/25,64%). A total of 22 cases (79%) obtained chromosome karyotype results, of which 7 were normal karyotypes, no complex karyotypes and 15 were abnormal karyotypes were found. Among abnormal karyotypes, there were 4 cases of t (9; 11), 2 cases of t (4; 11), 2 cases of t (11; 19), 1 case of t (1; 11) and 6 cases of other abnormal karyotypes. A total of 19 cases (68%) were positive for KMT2A-R detected by FISH. The KMT2A fusion gene was detected by real-time PCR in 16 cases (57%). A total of 24 patients completed standardized induction chemotherapy and were able to undergo efficacy evaluation, 23 cases (96%) achieved complete remission through induction chemotherapy, 4 cases (17%) died of relapse. The 5-year event free survival rate (EFS) was (46±13)%, and the 5-year overall survival rate (OS) was (73±10)%.The survival time was 31.3 (3.3, 62.5) months. There was no significant statistical difference in 5-year EFS ((46±14)% vs. (61±18)%) and 5-year OS ((64±13)% vs. (86±13)%) between the KMT2A-R positive group (15 cases) and the KMT2A-R negative group (9 cases) ( χ2=1.88, 1.47, P=0.170, 0.224). Conclusions:Most IALL patients were accompanied by KMT2A-R. They had poor tolerance to traditional chemotherapy, the relapse rate during treatment was high and the prognosis was poor.

The protein arginine methyltransferases(PRMTs)family has a wide range of molecular functions and is involved in the generation, development, proliferation and differentiation of hematopoietic cells in the stem cell development.In hematological malignancy diseases, PRMTs can be involved in many important biological processes including cell proliferation, cell cycle, gene transcription, and DNA damage repair through methylation pathways.The abnormal expression of PRMTs can lead to the occurrence and development of malignancy diseases, especially in childhood leukemia.Targeted PRMTs therapy can effectively inhibit the proliferation and survival of tumor cells by reducing the expression of PRMTs.Therefore, the relationship between PRMTs and hematological malignancy diseases has received much attention and is likely to become an important target for treatment in the future.This article reviews the role and mechanism of PRMTs in hematological malignancy diseases, in order to provide new strategies for the treatment of hematological malignancy diseases.

The overall survival rate of children with acute myeloid leukemia(AML) is significantly lower than that of acute lymphoblastic leukemia.The main causes of death include primary disease-related death and treatment-related death.Most of the treatment-related deaths are caused by infection, bleeding and organ failure.Infection is the most common complication of pediatric AML during the myelosuppression period after chemotherapy, and it is also the main cause of early death in AML.Based on the analysis of pathogens, laboratory tests and risk factors, this paper reviews the clinical characteristics and research progress of infection in myelosuppression following chemotherapy for AML, so as to provide a basis for early identification, clinical management and condition judgment, and further improve the survival rate of children with AML.

Acute lymphoblastic leukemia(ALL)is the most common malignant tumor in childhood, and T-ALL accounts for 10%~15% of all in children with ALL.Based on the application of MICM classification, risk stratification and multi-drugs intensive therapy, the prognosis of children with T-ALL has been improved, but the overall survival rate and event free survival rate are still less than 70%, and the overall survival rate of relapsed / refractory T-ALL is less than 10%.The treatment of T-ALL in children still faces great challenges.CDl9 targeted chimeric antigen receptor(CAR)modified T cells have shown impressive results in children with refractory B-ALL, with remission rate of 70%~90%.The emergence of CAR-T and CAR modified NK cells(CAR-NK)targeted therapy is expected to improve the prognosis of T-ALL in children.This article reviews the latest progress of CAR-T and CAR-NK in children with T-ALL.

Acute leukemia (AL) is the most common tumor in childhood.With the improvement of risk stratification therapy, the complete remission rate of AL has been significantly improved.However, central nervous system leukemia (CNSL) remains the major cause of recurrence and death of leukemia.This study aims to review the pathogenesis, diagnosis and treatment of CNSL in children, hoping to further improve the understanding.

To analyze the clinical characteristics, treatment and prognosis of mediastinal germ cell tumors (GCTs) with concurrent hematologic malignancy (HM). The clinical features, treatment and prognosis of 3 cases of HM associated with mediastinal GCTs treated in the Department of Medical Oncology, Beijing Children′s Hospital from November 2014 to September 2018 were retrospectively analyzed.Meanwhile, relevant cases were searched in the PubMed and Wanfang database from their establishment to December 2019.Three male cases of HM associated with mediastinal GCTs aged from 12 to 16 years.The pathogenesis of mediastinal masses suggested teratoma or yolk sac tumor.All of them were treated with surgery and chemotherapy.Acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) was diagnosed respectively at 5 months, 9 months and 31 months after initial GCTs in the 3 cases.Two patients died and 1 child survived at the last follow-up.A total of 135 cases of concurrent GCTs and HM (or leukemia) were reviewed in online databases, involving 127 cases (94.1%) with the mediastinal GCTs associated with HM and 8 cases(5.9%) with GCTs related HM from another original sites.One hundred and twenty-six cases (99.2%) were male and the median age of GCTs diagnosis was 22 (10-48) years.Fifty-three cases (41.7%) were teratoma and 94 cases (74.0%) were GCTs containing teratoma with or without yolk sac tumor.Among the types of HM, 72 cases (56.7%) were AML and 31 cases (24.4%) were AML-M7.The median interval between GCTs and HM was 3 (0-122) months.Forty-six cases (36.2%) presented 2 malignancies simultaneously.HM were diagnosed within 12 months of GCTs in 85 cases (66.9%). The survival data were known in 107 cases, involving 94 (87.9%) deaths and 13 (12.1%) survivors.The median survival time after diagnosis of HM was 2 (0-48) months.The tendency of HM must be highly concerned in adolescent male patients with primary mediastinal GCTs, especially those with yolk sac tumor or teratoma.Their prognoses are very poor.Allogeneic hematopoietic stem cell transplantation is an alternative treatment.