Dual-targeting chimeric antigen receptor (CAR)-T cell therapy has been proposed as a potential solution for overcoming antigen escape during anti-CD19 CAR-T treatment. We performed this systematic review and meta-analysis to investigate the efficacy and safety of this novel treatment in patients with B-cell non-Hodgkin lymphoma (B-NHL) and B-cell acute lymphoblastic leukemia (B-ALL). We systematically searched relevant literature based on databases (PubMed, Web of Science, Embase and Cochrane) and conference abstracts. The primary outcomes measured were the best objective response rate (ORR) or complete response (CR), 12-month overall survival (OS) and progression-free survival (PFS), cytokine release syndrome (CRS) and neurotoxicity. Fifteen registered prospective open-label clinical trials were included. Among the 260 patients with B-NHL, the pooled best ORR and CR were 77% (95% CI: 0.71-0.82) and 52% (95% CI: 0.40-0.63), respectively, and the pooled 12-month PFS and OS were 54.0% (95% CI: 0.47-0.61) and 66.0% (95% CI: 0.56-0.77), respectively. In the 159 patients with B-ALL, the combined best CR was observed to be 92% (95% CI: 0.82-0.99) and the pooled 12-month PFS and OS were 65.0% (95% CI: 0.51-0.77) and 73.0% (95% CI: 0.56-0.92), respectively. Moreover, in B-NHL patients, grade ≥3 CRS was observed in 14.0% (95% CI: 0.04-0.29) of these patients, and 5.0% (95% CI: 0.02-0.08) showed grade ≥3 neurotoxicity; in the case of B-ALL patients, grade ≥3 CRS and neurotoxicity occurred in 11.0% (95% CI: 0.04-0.19) and 2.0% (95% CI: 0.00-0.06), respectively. This study demonstrates the safety and clinical efficacy of dual-targeting CAR-T cell therapies in B-cell malignancies. Further well-designed randomized controlled trials are required to establish the role of dual-targeting CAR-T cell therapy in patients with B-cell malignancies.

Patient responses to autologous CD19 chimeric antigen receptor (CAR) T-cell therapies are limited by insufficient and inconsistent cellular functionality. Here, we show that controlling the precise level of stimulation during T-cell activation to accommodate individual differences in the donor cells will dictate the functional attributes of CAR-T cell products. The functionality of CAR-T cell products, consisting of a diverse set of blood samples derived from healthy donors, acute lymphoblastic leukemia (ALL), and chronic lymphocytic lymphoma (CLL) patient samples, representing a range of patient health status, is tested upon culturing on artificial antigen-presenting cell scaffolds to deliver T-cell stimulatory ligands (anti-CD3/anti-CD28) at highly defined densities. A clear relationship is observed between the dose of stimulation, the phenotype of the T-cell blood sample prior to T-cell activation, and the functionality of the resulting CAR-T cell products. We present a model, based on this dataset, that predicts the precise stimulation needed to manufacture a desired CAR-T cell product, given the input T-cell attributes in the initial blood sample. These findings demonstrate a simple approach to enhance CAR-T functionality by personalizing the level of stimulation during T-cell activation to enable flexible manufacturing of more consistent and potent CAR-T cells.

Olverembatinib represents the third-generation breakpoint cluster region protein-Abelson-murine leukemia 1 (BCR-ABL1) tyrosine kinase inhibitor with oral bioavailability, which can be used to overcome the T315I mutation in Philadelphia chromosome-positive (Ph +) leukemia. BCR-ABL-independent resistance to olverembatinib has been reported among patients in various clinical cases. However, the mechanism of olverembatinib resistance has rarely been reported. This study has illustrated bone marrow cell transcriptome and metabolome profiles among Ph + acute lymphoblastic leukemias (ALL) cases pre- and post-olverembatinib resistance. The transcriptome studies demonstrated that PI3K/AKT, purine metabolism, and other signaling pathways could play a vital role in olverembatinib resistance. As suggested by metabolomics, olverembatinib resistance in Ph + ALL was associated with purine metabolism alterations. Subsequently, high-performance liquid chromatography along with real-time quantitative PCR was utilized to measure purine metabolism-related mRNA levels and metabolism expression levels between olverembatinib resistance and sensitive cell lines. Our results elucidate the mechanism of olverembatinib resistance in Ph + ALL at transcriptome and metabolome levels, which facilitate a better understanding of olverembatinib resistance and hence may prove crucial in identifying novel drugs to tackle this conundrum.

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, constituting approximately 25% of childhood cancers. In recent decades, survival rates have improved dramatically, from approximately 10% in the 1960's to over 90% today. This tremendous achievement has been accomplished through collaborative randomized clinical trials, with progressive evolution of highly efficient, risk-adapted multi-agent chemotherapeutic regimens, effective central nervous system prophylactic strategies and improved supportive care. Recently, our understanding of the genetic basis of ALL has been greatly enhanced, and precise methods for treatment response assessment with serial measurements of minimal residual disease have been developed. Certain patient subgroups have genetically targetable lesions, such as Philadelphia-positive ALL, whose outcomes have been dramatically improved by combined tyrosine kinase inhibitors and chemotherapy, or specific patient subsets of "Philadelphia-like" ALL. Despite the great progress in curing childhood ALL, significant challenges still remain. Acute adverse effects of chemotherapy may be life-threatening, and long-term side effects often impair survivors' quality of life. Survival rates in patients with relapsed or refractory ALL remain poor. This led to the introduction of novel immune-based therapies into the treatment of relapsed/refractory B-ALL: blinatumomab, a CD19 bi-specific T-cell engager; inotuzumab- a CD22-immunotoxin, and CD19-CAR (chimeric antigen receptor) T cells. These modalities have demonstrated improved remission rates with reduced toxicity compared to chemotherapy. The role of immunotherapy in the treatment of newly-diagnosed and relapsed patients will be more precisely defined in the near future.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood, arising from the bone marrow. ALL may present at diagnosis or relapse at extramedullary sites. In recent years, autologous T-cells engineered to express a chimeric-antigen receptor (CAR-T cells) have emerged as novel immune-based therapies for relapsed and refractory ALL, targeting the B-cell surface antigen CD19. Here we present a patient with relapsed ALL involving the ovaries, treated with CD19 CAR-T cells. Toxicity included cytokine-release syndrome and neurotoxicity. CAR-T cell therapy led to a complete remission, with evidence of CAR-T cell trafficking to disease sites including the bone marrow and ovaries.

Activated Notch signaling is highly prevalent in T-cell acute lymphoblastic leukemia (T-ALL) but pan-Notch inhibitors were toxic in clinical trials. To find alternative ways to target Notch signals, we investigated Cell division cycle 73 (Cdc73), which is a Notch cofactor and component of transcriptional machinery, a potential target in T-ALL. While we confirmed previous work that CDC73 interacts with NOTCH1, we also found that the interaction in T-ALL was context-dependent and facilitated by the lymphoid transcription factor ETS1. Using mouse models, we showed that Cdc73 is important for Notch-induced T-cell development and T-ALL maintenance. Mechanistically, Cdc73, Ets1, and Notch intersect chromatin at promoters and enhancers to activate oncogenes and genes that are important for DNA repair and oxidative phosphorylation. Consistently, Cdc73 deletion in T-ALL cells induced DNA damage and impaired mitochondrial function. Our data suggests that Cdc73 might promote a gene expression program that was eventually intersected by Notch to mitigate the genotoxic and metabolic stresses of elevated Notch signaling. We also provide mechanistic support for testing inhibitors of DNA repair, oxidative phosphorylation, and transcriptional machinery. Inhibiting pathways like Cdc73 that intersect with Notch at chromatin might constitute a strategy to weaken Notch signals without directly targeting the Notch complex.

Objective: Comparison of conventional chemotherapy and immunotargeted therapy efficacy in patients with relapsed/refractory (R/R) acute B cell leukemia (B-ALL) . Methods: The clinical data of 212 patients with R/R B-ALL in the Affiliaed Cancer Hospital of Zhengzhou University from January 2008 to July 2020 were analyzed retrospectively to compare the response rate and survival time difference between conventional chemotherapy and immunotargeted therapies (antiCD19 CAR-T and CD3CD19 bi-specific antibody blinatumomab) , and to explore the related factors affecting prognosis. Results: The CR rate of patients with R/R B-ALL treated with anti-CD19 CAR-T cells was 80.4% , patients treated with blinatumomab was 62.5% , and patients treated with chemotherapy was 38.6% . There was significant difference in the CR rate among the three therapies (P<0.001) . CAR-T cells 1-year OS rate was 41.5% , which was significantly higher than that of the chemotherapy group (10.3% ) (P<0.001) . The 1-year PFS rate of CAR-T cells (30.1% ) was also significantly higher than that of the chemotherapy group (9.7% ) (P<0.001) . The median OS of patients with bridging allo-HSCT after CR treatment by CAR-T cells was 18.5 months, which was higher than that of patients without allo-HSCT (8 months) (P=0.027) . The median PFS of patients with allo-HSCT was 17 months, which was higher than that of patients without allo-HSCT (4 months) (P=0.001) . The 1-year OS rate of patients treated with blinatumomab was 14.3% , which was higher than that of the chemotherapy group (10.3% ) (P=0.018) . The 1-year PFS rate (14.6% ) was also higher than that of the chemotherapy group (9.7% ) (P=0.046) . The median OS and median PFS of patients with bridging allo-HSCT were 13 and 11 months, respectively, which was higher than that of patients without allo-HSCT (9.5 and 6 months) . The cytokine release syndrome (CRS) incidence in patients with R/R B-ALL treated with anti-CAR-T cells was 89.8% . Grades 3-4, grade 2, and grade 1 CRS were experienced by 30.2% , 11.3% and 58.5% patients, respectively. Only three patients (37.5% ) with blinatumomab developed CRS, all of which were grade 1. Conclusion: The response rate and survival rate of patients with R/R B-ALL treated with CD19 CAR-T cells and blinatumomab were significantly better than those treated with conventional chemotherapy.

Objective: This study aimed to evaluate the safety and efficacy of humanized CD19-targeted chimeric antigen receptor T-cell (CAR-T) in patients with relapsed/refractory acute B cell lymphoblastic leukemia (R/R B-ALL) . Methods: The clinical data of 41 patients with R/R B-ALL treated with humanized CD19-targeted CAR-T cells in the First Affiliated Hospital of Zhejiang University School of Medicine from February 2020 to July 2021 were analyzed. Results: Cytokine release syndrome occurred in all patients, and 63.4% (26/41) were grades 1-2. Immune effector cell-associated neurotoxicity syndrome developed in three patients. On median day 15 (9-47) , the complete remission rate was 95.1% (39/41) , of which 38 patients tested negative for bone marrow minimal residual disease detected by flow cytometry. Among the 39 patients with complete remission, 17 patients did not receive further treatment, and 70.6% (12/17) remained in remission at the end of follow-up, with a progression-free survival of 11.6 months of the two patients with the earliest infusion. Another 17 patients underwent consolidation allogeneic hematopoietic stem cell transplantation (10 cases) or CD22 CAR-T cell sequential therapy (seven cases) after remission, and 76.5% (13/17) of the patients were still in remission at the end of follow-up. The remaining five patients who did not receive consolidation therapy relapsed at a median of 72 (55-115) days after CAR-T cell therapy. Conclusion: In patients with R/R B-ALL, the humanized CD19-targeted CAR-T cells had a high response and manageable toxicity.

Objective: To investigate the efficacy and safety of humanized CD19-specific chimeric antigen receptor T cells (hCART19s) in treating children and young adults with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) and to analyze relevant factors affecting its curative effect and prognosis. Methods: We conducted a single-center clinical trial involving 31 children and young adult patients with R/R B-ALL who were treated with humanized CD19-specific CAR-T cells (hCART19s) from May 2016 to September 2021. Results: Results showed that 27 (87.1%) patients achieved complete remission (CR) or CR with incomplete count recovery (CRi) one month after CAR-T cell infusion. During treatment, 20 (64.5%) patients developed grade 1-2 cytokine release syndrome (CRS) , and 4 (12.9%) developed grade 3 CRS. Additionally, two patients had grade 1 neurological events. During the follow-up with a median time of 19.3 months, the median event-free survival (EFS) was 15.7 months (95% CI 8.7-22.5) , and the median overall survival (OS) was 32.2 months (95% CI 10.6-53.9) . EFS and OS rates were higher in patients who have undergone hemopoietic stem cell transplantation (HSCT) than in those without [EFS: (75.0 ± 12.5) % vs (21.1 ± 9.4) %, P=0.012; OS: (75.0 ± 12.5) % vs (24.6 ± 10.2) %, P=0.035]. The EFS and OS rates were significantly lower in patients with >3 treatment lines than in those with <3 treatment lines [EFS: 0 vs (49.5±10.4) %, P<0.001; OS: 0 vs (52.0±10.8) %, P<0.001]. To the cutoff date, 12 patients presented with CD19(+) relapse, and 1 had CD19(-) relapse. Conclusion: hCART19s are effective in treating pediatric and young adult R/R ALL patients, with a low incidence of severe adverse events and reversible symptoms. Following HSCT, the number of treatment lines can affect the long-term efficacy and prognosis of pediatric and young adult R/R ALL patients.

Objective: The study aims to explore the efficacy and safety of low-dose chemotherapy combined with tyrosine kinase inhibitor (TKI) as an induction therapy for Philadelphia-chromosomal-positive acute lymphoblastic leukemia (Ph(+) ALL) . Methods: The data of the consecutive newly diagnosed patients with Ph(+) ALL were reviewed. The efficacy and safety of low-dose chemotherapy and conventional-dose chemotherapy combined with TKI were compared. Results: A total of 217 patients with a median age of 38 (10-69) years old were included in this study. 78 patients were in the low-dose chemotherapy group, and 139 patients were in the conventional-dose chemotherapy group. There were no significant differences in the 4-week complete remission (CR) rate (98.7% vs 97.0%, P=0.766) and overall CR rate (100% vs 100%, P=1.000) between the two groups. Multivariate analyses showed that the chemotherapy intensity was not related to the disease-free survival rate and overall survival rate. However, the lower incidence of infection (P=0.017) , the shorter duration of neutropenia (P=0.001) and PLT<20 × 10(9)/L (P=0.057) , and the lower red blood cell transfusion volume (P=0.002) were more common in the low-dose chemotherapy group than in the conventional-dose chemotherapy group. Conclusions: The low-dose chemotherapy is superior to the conventional-dose chemotherapy combined with TKI as induction therapy in Ph(+) ALL with similar efficacy but is safer.

Objegtive: To investigate the efficacy and safety of preemptive/salvage therapy with venetoclax (VEN) in patients with recurrence after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: Retrospective analysis the clinical data of 25 patients with minimal residual disease (MRD) positive or morphological recurrence after allo-HSCT treated with VEN in the hematological Hospital of Chinese Academy of Medical Sciences from 2021.2 to 2021.11, there were 15 MRD positive patients (preemptive treatment group) and 10 morphological recurrence patients (salvage treatment group) . The dose of VEN in both groups was 400 mg/d, which was reduced to 100 mg/d when combined with azole antifungal drugs. Results: ①In the preemptive group, there were 7 males and 8 females, with a median age of 32 (18-52) years; There were 13 cases of acute myeloid leukemia (AML) , 1 case of acute lymphoblastic leukemia (ALL) and 1 case of primary myelofibrosis (PMF) ; the median time from MRD positive to the application of VEN was 2.5 (0-12.5) months. The median course of treatment was 2 (1-4) . On the 7th day of the first course of treatment, the median concentration of VEN was 1945 (688-5383) μg/L. After one course of VEN treatment, MRD in 8 patients turned negative (major responses) , MRD in 4 patients decreased by 50% compared with that before treatment, 3 cases were ineffective, and the overall response rate (ORR) was 80% (12/15) . On the 7th day of treatment, 3 of the 9 patients with VEN blood concentration <1 000 μg/L or >3 000 μg/L turned negative for MRD (33.3%) , and 5 of the 6 patients with VEN blood concentration between 1000 and 3000 μg/L turned negative for MRD (83.3%) . Grade 3/4 neutropenia occurred in 5 patients (33%) and grade 3/4 thrombocytopenia occurred in 5 patients (33%) , there were no new cases of severe infection and death. ②In the salvage group, there were 7 males and 3 females, with a median age of 44 (28-59) years; there were 6 cases of AML, 2 cases of ALL, 1 case of atypical chronic myeloid leukemia (aCML) , 1 case of refractory hemopenia with multiline dysplasia (MDS-RCMD) ; the median time from relapse to application of VEN was 0 (0-1) months. The median treatment was 1 (1-2) course. The median concentration of VEN on the 7th day of the first course of treatment was 2 419 (1 200-6 155) μg/L. After one course of VEN treatment, 3 cases achieved complete remission (CR) (major responses) and 3 cases achieved partial remission (PR) , 4 cases were ineffective and the ORR was 60% (6/10) . On the 7th day of treatment, 1 of the 4 patients with VEN blood concentration >3 000 μg/L achieved CR (25%) , and 2 of the 6 patients with VEN blood concentration between 1 000 and 3 000 μg/L achieved CR (33.3%) . Grade 3/4 neutropenia and grade 3/4 thrombocytopenia occurred in 10 patients (100%) . One patient died of severe pulmonary infection. ③The median follow-up was 4.5 (1-8.5) months. The overall survival rate (OS) of the preemptive group and the salvage group were (70.2±12.7) % and (50.0± 15.8) %, respectively (χ(2)=1.873, P=0.171) . The OS of patients with and without primary response to one course of VEN were (90.9±8.7) % and (36.2±14.7) % respectively (χ(2)=6.843, P=0.009) . Three patients with TP53 mutation achieved the major responses after VEN treatment. Conclusion: Preemptive/salvage therapy with VEN after allo-HSCT in patients with hematological malignancies is effective and well tolerated, monitoring the concentration of VEN is expected to improve the curative effect. The prognosis of patients who fail to reach the major responses after one course of preemptive/salvage treatment with VEN is poor, so they need to switch to other treatment schemes as soon as possible.

NK-lymphoblastic leukemia/lymphoma (NK-LL) is an extremely rare hematopoietic tumor consisting of natural killer (NK) precursor cells, and their lineage overlaps with T-cells, making it challenging to diagnose. COVID-19 vaccination is recommended for people with a risk of aggravation such as cancer-bearing patients, including hematopoietic tumors. We present a 55-year-old man who had cervical lymph node swelling post vaccination for COVID-19. Hematological malignancy was suspected due to the presence of atypical lymphoid cells with an elevated IL-2R in laboratory data. Tumor cells were positive for CD7, CD56, cyCD3, and terminal deoxynucleotidyl transferase (TdT) evidenced through flow cytometry of the bone marrow and the lymph node. The histopathological findings showed monotonous tumor cell proliferation, the cells being positive for CD3 and TdT in the bone marrow and they were positive for CD3, TdT, and CD56 in lymph node. Even though these findings suggested NK-LL, clonal T-cell receptor (TCR) β gene rearrangement by Southern blot hybridization was observed in the bone marrow. TCRβ rearrangement led to the final diagnosis of T-cell lymphoblastic leukemia (T-ALL). The causal relationship between COVID-19 vaccination and carcinogenesis is not clear, and more cases need to be studied in order to elucidate the relationship between the two factors.

Acute lymphoblastic leukemia (ALL) is a hematologic cancer that begins in the bone marrow and results in an overproduction of lymphocytes. It can present as palpable purpura, which is also seen in many other pathologies, including vasculitides such as IgA vasculitis. We present a case of a 52-year-old male who presented to our hospital from an outside facility specifically for plasma exchange for treating a previously diagnosed IgA vasculitis. After being admitted for further evaluation, it was noted that the patient had a diffuse petechial non-blanching purpuric rash bilaterally covering the lower extremities, trunk, upper extremities, and tongue. The patient was also noted to have severe pancytopenia. Fluorescence in situ hybridization (FISH) demonstrated the presence of t(9:22), indicating Philadelphia chromosome rearrangement. The patient was diagnosed with ALL. The patient underwent induction chemotherapy and was continued on hyper-CVAD protocol with intrathecal chemotherapy. The patient appeared to respond well to treatment and is currently undergoing subsequent intermittent chemotherapy. In this case, the diagnosis of B-cell ALL (B-ALL) blast crisis was pivotal in providing the correct therapy to this patient, and the case demonstrated that even rare presentations of B-ALL in this population with rare mutations responds avidly to tyrosine kinase inhibitors.

Cardiac involvement in hematological malignancies is uncommon, with only a few cases reported to date, and it often leads to a poor prognosis. Here, we report a case of a 42-year-old woman with a history of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and anti-CD19 chimeric antigen receptor (CAR) T-cell therapy for B-cell lymphoblastic lymphoma/acute lymphoblastic leukemia in whom cardiac mass and myocardial infiltration were detected. Prior to this presentation, massive pericardial effusion had occurred 6 months after CAR T-cell therapy, which was improved via ultrasound-guided pericardiocentesis. We observed elevated cytokine levels and increased copy number of CAR DNA in both pericardial effusion and serum. Upon detecting cardiac mass and myocardial infiltration, the patient was administered tocilizumab (a humanized monoclonal antibody against IL-6 receptor), which controlled the serum cytokine levels, and reduced intensity chemotherapy, including vindesine, cyclophosphamide, and prednisolone. However, the patient finally died of multiple organ failure. To the best of our knowledge, this is the first report on the development of a cardiac mass and occurrence of myocardial infiltration after allo-HSCT and CAR T-cell therapy. This report may provide supporting data for the early diagnosis and immediate treatment of patients with cardiac involvement.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological disease that arises from the oncogenic transformation of developing T cells during T-lymphopoiesis. Although T-ALL prognosis has improved markedly in recent years, relapsing and refractory patients with dismal outcomes still represent a major clinical issue. Consequently, understanding the pathological mechanisms that lead to the appearance of this malignancy and developing novel and more effective targeted therapies is an urgent need. Since the discovery in 2004 that a major proportion of T-ALL patients carry activating mutations that turn NOTCH1 into an oncogene, great efforts have been made to decipher the mechanisms underlying constitutive NOTCH1 activation, with the aim of understanding how NOTCH1 dysregulation converts the physiological NOTCH1-dependent T-cell developmental program into a pathological T-cell transformation process. Several molecular players have so far been shown to cooperate with NOTCH1 in this oncogenic process, and different therapeutic strategies have been developed to specifically target NOTCH1-dependent T-ALLs. Here, we comprehensively analyze the molecular bases of the cross-talk between NOTCH1 and cooperating partners critically involved in the generation and/or maintenance and progression of T-ALL and discuss novel opportunities and therapeutic approaches that current knowledge may open for future treatment of T-ALL patients.

Numerous hematologic neoplasms, including acute B-lymphoblastic leukemia (B-ALL), are characterized by overexpression of anti-apoptotic BCL-2 family proteins. Despite the high clinical efficacy of the specific BCL-2 inhibitor venetoclax in acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL), dose limitation and resistance argue for the early exploration of rational combination strategies. Recent data indicated that BCL-2 inhibition in B-ALL with KMT2A rearrangements is a promising intervention option; however, combinatorial approaches have not been in focus so far. The PI3K/AKT pathway has emerged as a possible target structure due to multiple interactions with the apoptosis cascade as well as relevant dysregulation in B-ALL. Herein, we demonstrate for the first time that combined BCL-2 and PI3K/AKT inhibition has synergistic anti-proliferative effects on B-ALL cell lines. Of note, all tested combinations (venetoclax + PI3K inhibitors idelalisib or BKM-120, as well as AKT inhibitors MK-2206 or perifosine) achieved comparable anti-leukemic effects. In a detailed analysis of apoptotic processes, among the PI3K/AKT inhibitors only perifosine resulted in an increased rate of apoptotic cells. Furthermore, the combination of venetoclax and perifosine synergistically enhanced the activity of the intrinsic apoptosis pathway. Subsequent gene expression studies identified the pro-apoptotic gene BBC3 as a possible player in synergistic action. All combinatorial approaches additionally modulated extrinsic apoptosis pathway genes. The present study provides rational combination strategies involving selective BCL-2 and PI3K/AKT inhibition in B-ALL cell lines. Furthermore, we identified a potential mechanistic background of the synergistic activity of combined venetoclax and perifosine application.

Allogeneic stem cell transplantation (allo-SCT) represented the first immunotherapy to treat hematologic malignancies: it has been considered as a cure for the disease and never as an approach to extend the life of patients. The success of allo-SCT derives both from the ability to treat patients with intensive chemoradiotherapy and from the potent graft-versus-leukemia effects mediated by donor immunity. Although considerable progress has been made in the last years, significant barriers still remain in the form of disease relapse, graft-versus-host disease, infectious complications, and regimen-related toxicities. Moreover, the treatment of hematologic malignancies, particularly acute lymphoblastic leukemia and certain forms of lymphomas, has been revolutionized by the commercial introduction of genetically modified autologous T-lymphocyte therapy (CAR-T). Our review discusses current standards and the shifting paradigms in the indications for allo-SCT and the role of CAR-T cell therapy for lymphoid neoplasms.

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a frequent type of childhood hematological malignancy. The disease is classified into several subtypes according to genetic abnormalities. MicroRNAs (miRNAs) are involved in pathological processes (e.g., proliferation, apoptosis, differentiation). A miRNA is a group of short non-coding RNAs with relevant regulatory effects on gene expression achieved by suppression of the translation or degradation of messenger RNA (mRNA). These molecules act as tumor suppressors and/or oncogenes in the pathogenesis of pediatric leukemias. The characteristic features of miRNAs are their stable form and the possibility of secretion to the circulatory system. The role of miRNA in BCP-ALL pathogenesis is still emerging, but several studies have suggested using miRNA expression profiles as biomarkers for diagnosis, prognosis, and response to therapy in leukemia. The dysregulation of some miRNAs involved in childhood acute lymphoid leukemia, such as miR-155, miR-200c, miR-100, miR-181a, miR125b, and miR146a is discussed, showing their possible employment as therapeutic targets. In the current review, the capabilities of miRNAs in non-invasive diagnostics and their prognostic potential as biomarkers are presented.

6-mercaptopurine (6-MP) is a key component in maintenance therapy for childhood acute lymphoblastic leukemia (ALL). Recent next-generation sequencing analysis of childhood ALL clarified the emergence of the relapse-specific mutations of the NT5C2 and PRPS1 gene, which are involved in thiopurine metabolism. In this scenario, minor clones of leukemia cells could acquire the 6-MP resistant phenotype as a result of the NT5C2 or PRPS1 mutation during chemotherapy (including 6-MP treatment), and confer disease relapse after selective expansion. Thus, to establish new therapeutic modalities overcoming 6-MP resistance in relapsed ALL, human leukemia models with NT5C2 and PRPS1 mutations in the intrinsic genes are urgently required. Here, mimicking the initiation process of the above clinical course, we sought to induce two relapse-specific hotspot mutations (R39Q mutation of the NT5C2 gene and S103N mutation of the PRPS1 gene) into a human lymphoid leukemia cell line by homologous recombination (HR) using the CRISPR/Cas9 system. After 6-MP selection of the cells transfected with Cas9 combined with single-guide RNA and donor DNA templates specific for either of two mutations, we obtained the sublines with the intended NT5C2-R39Q and PRPS1-S103N mutation as a result of HR. Moreover, diverse in-frame small insertion/deletions were also confirmed in the 6-MP-resistant sublines at the target sites of the NT5C2 and PRPS1 gene as a result of non-homologous end-joining. These sublines are useful for molecular pharmacological evaluation of the NT5C2 and PRPS1 gene mutations in the 6-MP sensitivity and development of therapy overcoming the thiopurine resistance of leukemia cells. Significance Statement Mimicking the initiation process of relapse-specific mutations of the NT5C2 and PRPS1 genes in childhood acute lymphoblastic leukemia treated with 6-mercaptopurine (6-MP), we sought to introduce NT5C2-R39Q and PRPS1-S103N mutations into a human lymphoid leukemia cell line by homologous recombination using the CRISPR/Cas9 system. In the resultant 6-MP-resistant sublines, the intended mutations and diverse in-frame small insertions/deletions were confirmed, indicating that the obtained sublines are useful for molecular pharmacological evaluation of the NT5C2 and PRPS1 gene mutations.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and young adults. Treatment is long and involves 2-3 years of a prolonged maintenance phase composed of oral chemotherapies. Adherence to these medications is critical to achieving good outcomes. However, adherence is difficult to determine, as there is currently no consensus on measures of adherence or criteria to determine nonadherence. Furthermore, there have been few studies in pediatric B-ALL describing factors associated with nonadherence. Thus, we performed a systematic review of literature on oral chemotherapy adherence during maintenance therapy in ALL following PRISMA guidelines. Published studies demonstrated various objective and subjective methods of assessing adherence without generalizable definitions of nonadherence. However, the results of these studies suggested that nonadherence to oral maintenance chemotherapy was associated with increased risk of relapse. Future studies of B-ALL therapy should utilize a uniform assessment of adherence and definitions of nonadherence to better determine the impact of nonadherence on B-ALL outcomes and identify predictors of nonadherence that could yield targets for adherence improving interventions.

Due to the poor prognosis of T-cell acute lymphoblastic leukaemia (T-ALL), there is an urgent need to identify safer and more cost-effective drugs.

"Lineage switch" is term described when leukemic cells on relapse exhibit a new phenotype, where losses of one lineage defining markers with simultaneous gain of another lineage defining markers occur. Relapse of acute leukemia is although a very common event, lineage switch occurs and reported very rarely in such cases. The pathogenesis involved in this phenomenon remains unclear; however plasticity of hematopoietic progenitor affected by intrinsic and extrinsic environmental cues can be a possible explanation. In most of the cases at the time of relapse conversion of B-acute lymphoblastic leukemia (ALL) to acute myeloid leukemia (AML) occurs. Here, we presented an unusual case of 10 year old boy with AML switched to T-ALL upon relapse, which is very rare and not well documented till date in literature. The diagnosis was further supported by morphologic, cytochemistry and flowcytometric immunophenotyping (FCM-IPT). Prognosis and survival of such cases remains poor even by the use of standard chemotherapy.