Targeted therapy using larotrectinib and venetoclax for the relapsed/refractory T-cell acute lymphoblastic leukemia harboring a cryptic ETV6-NTRK3 fusion.

Outcomes for patients with relapsed and refractory (R/R) T-cell acute lymphoblastic leukemia (T-ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are dismal, with few available treatments. Recently, identification of cancer patients harboring neurotrophic tropomyosin receptor kinase (NTRK) gene fusions is constantly increasing, especially with the advent of NTRK inhibitors. However, the role of ETV6-NTRK3 in T-ALL has not been investigated. This case represented the first detailed report of T-ALL patient harboring a cryptic ETV6-NTRK3 fusion with an unfavorable prognosis, not only because of leukemia resistant to the standard multiagent chemotherapy but also early relapse after allo-HSCT. Acquired EP300 mutation was found at relapse, which could explain the cause of recurrence and affect the follow-up treatment. Combined targeted therapy like larotrectinib allied with pan-targeted BCL-2 inhibitor venetoclax, may be a potential maintenance treatment in R/R ETV6-NTRK3 positive leukemia after allo-HSCT. The leukemic clonal evolution might be revealed through transcriptome sequencing and overcome by drugs with universal targets. Our case demonstrated that both comprehensive profiling techniques (such as transcriptome sequencing, multiparameter flow cytometry, and digital droplet polymerase chain reaction) and a multimodality treatment strategy were critical for anticipating an early relapse and personalized therapy of R/R T-cell leukemia.

Role of brentuximab vedotin plus sirolimus in the treatment of classical Hodgkin lymphoma type post-transplant lymphoproliferative disorder: a case-based review.

Post-transplant lymphoproliferative disorder (PTLD) is a common secondary malignancy after transplantation, which has been recognized as a life-threatening complication. Hodgkin lymphoma (HL)-type PTLD is the rarest of four subtypes of PTLD, which has no treatment guideline due to its rarity. HL-type PTLD includes classical HL-type PTLD (cHL-PTLD) and HL-like PTLD. In our study, we reported the case of successful treatment using brentuximab vedotin (BV) plus sirolimus for a patient with classical HL-type PTLD in detail. Lymph node biopsy showed a picture of classical HL with mixed cellularity subtype, and immunophenotyping suggested CD30 strong positivity. Due to his impaired physical condition, we decided against intensive chemotherapy and started BV treatment with immunosuppressive agents switched to sirolimus. The 66-year-old patient with cHL-PTLD had achieved a durable complete remission for over a 1-year follow-up period. Additionally, we analyzed the clinical profile and outcomes in PTLD patients who used BV monotherapy or combined therapy by literature review. In summary, this case-based review might provide clues that treatment of cHL-PTLD with new modalities such as BV monotherapy or combination therapy, together with improvements in the immunosuppressive regimens like sirolimus, might be a feasible and chemotherapy-free approach, but warrants further evaluation in a larger patient cohort.

Loss of MBD2 affects early T cell development by inhibiting the WNT signaling pathway.

DNA methylation alters the expression of certain genes without any alteration to the DNA sequence and is a dynamic process during normal hematopoietic differentiation. As an epigenetic regulator, methyl-CpG-binding domain protein 2 (MBD2) is an important member of the MBD protein family and is acknowledged as a "reader" of DNA methylation. We used a mouse model to study the effects of MBD2 on the early development of T cells. Here, we found that MBD2 deficiency led to retardation of T cell differentiation at the DN3 stage. Meanwhile, decreased proliferative capacity and increased apoptosis were detected in Mbd2-/- DN thymocytes. Furthermore, we found the WNT pathway was significantly down-regulated in Mbd2-/- DN thymocytes: DKK1 (Dickkopf-1) expression was significantly increased, while TCF7 (transcription factor 7) and c-MYC were down-regulated. Thus, these findings established that MBD2 acted as a dominant regulator to imprint DN T cell development via the WNT pathway.

Treatment of Refractory p53 Mutation Large B-cell Lymphoma with Daratumumab and Venetoclax Followed by CAR-T Cell Therapy: Case Report and Animal Study.

BACKGROUND: The tumor burden before chimeric antigen receptor T (CAR-T) cell therapy was one of the critical factors affecting the prognosis of lymphoma. It was a challenge to effectively reduce the tumor burden of relapsed/refractory large B-cell lymphoma with p53 mutation. OBJECTIVE: Here, we have presented a case of relapsed/refractory large B-cell lymphoma with p53 mutation being controlled by the treatment with daratumumab and venetoclax, followed by CAR-T cell therapy. CASE PRESENTATION: The patient was a 56-year-old female who was diagnosed with relapsed/ refractory diffuse large B cell lymphoma (DLBCL) transformed from follicular lymphoma. The patient was treated with daratumumab, venetoclax, and GEMOX (gemcitabine and oxaliplatin) under the guidance of high-throughput drug sensitivity analysis. We used a CD38 positive lymphoma cell line with p53 mutation to construct tumor models for validating the anti- lymphoma effect of the combination therapy of daratumumab and venetoclax. RESULTS: The patient achieved a complete metabolic response after treatment with daratumumab, venetoclax, and GEMOX. Then, she further achieved a complete molecular response after she subsequently received CAR-T cell therapy, and she has been living without a lymphoma recurrence. The results from the animal study showed that the combination of daratumumab and venetoclax could significantly enhance the antitumor effect on CD38-positive lymphoma with p53 mutation. CONCLUSION: The results from our successful case and animal experiments provide new avenues for the treatment of relapsed/refractory large B-cell lymphoma with p53 mutation. Further clinical trials are reuqired to treat CD38-positive lymphoma with the combination of daratumumab and venetoclax.

Coexistence of primary mediastinal MALT lymphoma and multiple myeloma like POEMS syndrome: A case report and literature review.

RATIONALE: The coexistence of the extranidal marginal zone lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT) and multiple myeloma (MM) is an exceedingly rare situation. The rare situation precludes any evidence-based guidelines for MZL or MM. PATIENT CONCERNS AND DIAGNOSES: We presented a unique case of the coexistence of primary mediastinal MALT lymphoma and MM like polyneuropathy, organomegaly, endocrinopathy, M-protein, skin syndrome. INTERVENTIONS AND OUTCOMES: The patient was first diagnosed with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin syndrome in the department of neurology, then MM in the department of hematology, and the mediastinal MALT simultaneously coexisting with MM was found by biopsy in the department of thoracic surgery. The patient received combination therapy with rituximab and bortezomib followed by lenalidomide maintenance. To understand MZL lymphoma with plasmacytic differentiation better, we analyzed cases of MZL lymphomas with plasma cell neoplasms. Most of these cases were MZL lymphomas with light chain-restricted plasmacytic differentiation. The lymphomas relapsed with plasma cell neoplasms or transformed into plasma cell neoplasms after anti-lymphoma therapy. LESSONS: The case demonstrated clinical complexity and the importance of the detailed assessment. The case and literature review demonstrated the value of detecting light chain-restricted plasmacytic differentiation for the treatment of MZL lymphoma with rituximab plus lenalidomide or bortezomib.

CD137 deficiency because of two novel biallelic TNFRSF9 mutations in a patient presenting with severe EBV-associated lymphoproliferative disease.

Objectives: Increasing evidence indicates that some germline genetic mutations that impair pathways required for robust host immune surveillance against EBV infection may result in an extremely high susceptibility to EBV-associated lymphoproliferative disease (EBV+ LPD). TNFRSF9 encodes a vital costimulatory molecule that enhances CD8+ T-cell proliferation, survival and cytolytic activity. To date, no relevant case resulting from TNFRSF9 heterozygous mutations has been identified. Methods: Here, we report the first case of CD137 deficiency caused by two novel biallelic heterozygous TNFRSF9 mutations [NM_001561.5: c.208 + 1->AT and c.452C>A (p.T151K)] in a patient presenting with severe EBV+ LPD. Immunophenotyping and in vitro assays of lymphocyte function and NK cell activity were performed. Results: Biallelic TNFRSF9 mutations resulted in markedly reduced or abrogated expression of CD137 on activated T, B and NK cells. CD8+ T cells from the patient had impaired activation, reduced expression/release of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), perforin and granzyme B, and diminished cytotoxic activity. Functional experiments identified both variations were hypomorphic mutations and played a contributing role in CD137 deficiency and the development of EBV+ LPD. Conclusion: Our study expands the genetic spectrum and clinical phenotype of patients with CD137 deficiency and provides additional evidence that the TNFRSF9 gene plays a critical role in host immune responses to EBV infection.

Association between B-group vitamins and venous thrombosis: systematic review and meta-analysis of epidemiological studies.

A homocysteine-independent role for B-group vitamins on venous thrombosis (VT) development has been reported. However, related research findings remain inconsistent. PUBMED, EMBASE, and COCHRANE databases were searched to collect information on all eligible studies to make a meta-analysis about the relationship between B-group vitamins and VT. Literature search results did not suggest a correlation between thiamin, pantothenic acid, niacin, or riboflavin with VT. Based on their correlations in the literature, folic acid, vitamin B12, B6 were considered in the meta-analysis and systematic review. Significant standardized mean differences were obtained for plasma folic acid (-0.55; 95% CI, -0.75 to -0.36) and vitamin B12 (-0.34; 95% CI, -0.55 to -0.13). Reduced levels of folic acid and vitamin B12 may be independent risk factors of VT. Moreover, a qualitative systematic review indicated that low level of vitamin B6 was an independent risk factor of VT. Randomized clinical studies of B-group vitamins supplementation showed varying results on VT prevention. Multivitamin supplementation for VT prevention, regardless of homocysteine level, would be of interest. Further prospective clinical studies are needed to provide additional evidence on the clinical benefits of B-group vitamin supplementation for VT.

Case Report: Metagenomic Next-Generation Sequencing Can Contribute to the Diagnosis and Treatment of Disseminated Visceral Kaposi Sarcoma Following Allogeneic Haematopoietic Stem Cell Transplantation.

Disseminated visceral Kaposi sarcoma (KS) following allogeneic haematopoietic stem cell transplantation (HSCT) is a rare but life-threatening posttransplant complication. A suitable management strategy for disseminated KS involvement in transplant patients is unclear. Here, we reported a patient who developed disseminated visceral KS following HSCT, which was the first detailed report documenting the relationship among KS development, delayed immune reconstitution, and HHV-8 DNA levels by metagenomic next-generation sequencing (mNGS). The HHV-8 viral load peaked at 2071 sequence reads with an absolute lymphocyte count of 0.17×109/L on day +242. On day +536, the HHV-8 viral load became undetectable, with an absolute lymphocyte count of 1.06×109/L and the KS disappearance. HHV-8 load in blood detected by mNGS may be used as an early prediction marker for KS, a guide for early withdrawal of immunosuppression, and a tool to monitor KS treatment response in the setting of HSCT, especially in patients with CMV-seropositive or graft failure postengraftment. Through whole-exome sequencing, we explored the molecular mechanism underlying the patient's longer latency of haematopoietic or immune reconstitution and recurrent infections. Germline mutations in the FANCI and RAD51 genes might impair the patient's DNA repair ability, leading to a degree of immunodeficiency and tumour susceptibility. We strongly recommended evaluating the clinical history of the donor and investigating whether there were possible germline mutations suspected for immunodeficiency or familial neoplasms. Disseminated visceral KS patients could likely benefit from chemotherapy, especially if the disease appears to be aggressive.

Loss of MBD2 attenuates MLL-AF9-driven leukemogenesis by suppressing the leukemic cell cycle via CDKN1C.

Acute myeloid leukemia (AML) is a deadly cancer characterized by an expanded self-renewal capacity that is associated with the accumulation of immature myeloid cells. Emerging evidence shows that methyl-CpG-binding domain protein 2 (MBD2), a DNA methylation reader, often participates in the transcriptional silencing of hypermethylated genes in cancer cells. Nevertheless, the role of MBD2 in AML remains unclear. Herein, by using an MLL-AF9 murine model and a human AML cell line, we observed that loss of MBD2 could delay the initiation and progression of leukemia. MBD2 depletion significantly reduced the leukemia burden by decreasing the proportion of leukemic stem cells (LSCs) and inhibiting leukemia cell proliferation in serial transplantation experiments, thereby allowing leukemic blasts to transition to a more mature state reflecting normal myelopoiesis. Both gene expression analyses and bioinformatic studies revealed that MBD2 negatively modulated genes related to myeloid differentiation, and was necessary to sustain the MLL-AF9 oncogene-induced gene program. We further demonstrated that MBD2 could promote LSC cell cycle progression through epigenetic regulation of CDKN1C transcription probably by binding to its promoter region. Taken together, our data suggest that MBD2 promotes AML development and could be a therapeutic target for myeloid malignancies.

Combined inhibition of Notch and FLT3 produces synergistic cytotoxic effects in FLT3/ITD+ acute myeloid leukemia.

Internal tandem duplication (ITD) mutations of FMS-like tyrosine kinase-3 (FLT3) are the most frequent genetic alterations in acute myeloid leukemia (AML) and predict a poor prognosis. FLT3 tyrosine kinase inhibitors (TKIs) provide short-term clinical responses, but the long-term prognosis of FLT3/ITD+ AML patients remains poor. Notch signaling is important in numerous types of tumors. However, the role of Notch signaling in FLT3/ITD+ AML remains to be elucidated. In the current study, we found that Notch signaling was activated upon FLT3-TKI treatment in FLT3/ITD+ cell lines and primary cells. As Notch signaling can be blocked by γ-secretase inhibitors (GSIs), we examined the combinatorial antitumor efficacy of FLT3-TKIs and GSIs against FLT3/ITD+ AML and explored the underlying molecular mechanisms. As a result, we observed synergistic cytotoxic effects, and the treatment preferentially reduced cell proliferation and induced apoptosis in FLT3/ITD+ AML cell lines and in primary AML cells. Furthermore, the combination of FLT3-TKI and GSI eradicated leukemic cells and prolonged survival in an FLT3/ITD+ patient-derived xenograft AML model. Mechanistically, differential expression analysis suggested that CXCR3 may be partially responsible for the observed synergy, possibly through ERK signaling. Our findings suggest that combined therapies of FLT3-TKIs with GSI may be exploited as a potential therapeutic strategy to treat FLT3/ITD+ AML.

Deletion of MBD2 inhibits proliferation of chronic myeloid leukaemia blast phase cells.

Aberrant methylation of tumour suppressor genes is associated with the progression to a blast crisis in chronic myeloid leukaemia (CML). Methyl-CpG-binding domain protein 2 (MBD2) has been studied as a "reader" of DNA methylation in many cancers, but its role in CML is unclear. We constructed cell models of a homozygous deletion mutation of MBD2 using gene-editing technology in K562 cells and BV173 cells. Here, we demonstrated that the deletion of MBD2 inhibited cell proliferation capacity in vitro. MBD2 deletion also significantly inhibited K562 cell proliferation in a xenograft tumour model in vivo. Additionally, the JAK2/STAT3 signalling pathway, which is abnormally active in CML, was inhibited by MBD2 deletion, and MBD2 deletion could up-regulate the expression of SHP1. In conclusion, our findings suggest that MBD2 is a candidate therapeutic strategy for the CML blast phase.

MBD2 Ablation Impairs Lymphopoiesis and Impedes Progression and Maintenance of T-ALL.

Aberrant DNA methylation patterns in leukemia might be exploited for therapeutic targeting. In this study, we employed a genetically deficient mouse model to explore the role of the methylated DNA binding protein MBD2 in normal and malignant hematopoiesis. MBD2 ablation led to diminished lymphocytes. Functional defects of the lymphoid compartment were also observed after in vivo reconstitution of MBD2-deficient hematopoietic stem cells (HSC). In an established model of Notch1-driven T-cell acute lymphoblastic leukemia (T-ALL), MBD2 ablation impeded malignant progression and maintenance by attenuating the Wnt signaling pathway. In clinical specimens of human T-ALL, Wnt signaling pathway signatures were significantly enhanced and positively correlated with the expression and function of MBD2. Furthermore, a number of typical Wnt signaling inhibitory genes were abnormally hypermethylated in primary human T-ALL. Abnormal activation of Wnt signaling in T-ALL was switched off by MBD2 deletion, partially by reactivating epigenetically silenced Wnt signaling inhibitors. Taken together, our results define essential roles for MBD2 in lymphopoiesis and T-ALL and suggest MBD2 as a candidate therapeutic target in T-ALL.Significance: This study highlights a methylated DNA binding protein as a candidate therapeutic target to improve the treatment of T-cell acute lymphoblastic leukemias, as a new starting point for developing epigenetic therapy in this and other lymphoid malignancies. Cancer Res; 78(7); 1632-42. ©2018 AACR.

Integrated genomic analysis identifies deregulated JAK/STAT-MYC-biosynthesis axis in aggressive NK-cell leukemia.

Aggressive NK-cell leukemia (ANKL) is a rare form of NK cell neoplasm that is more prevalent among people from Asia and Central and South America. Patients usually die within days to months, even after receiving prompt therapeutic management. Here we performed the first comprehensive study of ANKL by integrating whole genome, transcriptome and targeted sequencing, cytokine array as well as functional assays. Mutations in the JAK-STAT pathway were identified in 48% (14/29) of ANKL patients, while the extracellular STAT3 stimulator IL10 was elevated by an average of 56-fold (P < 0.0001) in the plasma of all patients examined. Additional frequently mutated genes included TP53 (34%), TET2 (28%), CREBBP (21%) and MLL2 (21%). Patient NK leukemia cells showed prominent activation of STAT3 phosphorylation, MYC expression and transcriptional activities in multiple metabolic pathways. Functionally, STAT3 activation and MYC expression were critical for the proliferation and survival of ANKL cells. STAT signaling regulated the MYC transcription program, and both STAT signaling and MYC transcription were required to maintain the activation of nucleotide synthesis and glycolysis. Collectively, the JAK-STAT pathway represents a major target for genomic alterations and IL10 stimulation in ANKL. This newly discovered JAK/STAT-MYC-biosynthesis axis may provide opportunities for the development of novel therapeutic strategies in treating this subtype of leukemia.

C-MYC aberrations as prognostic factors in diffuse large B-cell lymphoma: a meta-analysis of epidemiological studies.

OBJECTIVES: Various studies have investigated the prognostic value of C-MYC aberrations in diffuse large B-cell lymphoma (DLBCL). However, the role of C-MYC as an independent prognostic factor in clinical practice remains controversial. A systematic review and meta-analysis were performed to clarify the clinical significance of C-MYC aberrations in DLBCL patients. METHODS: The pooled hazard ratios (HRs) for overall survival (OS) and event-free survival (EFS) were calculated as the main effect size estimates. The procedure was conducted according to the Cochrane handbook and PRISMA guidelines, including the use of a heterogeneity test, publication bias assessment, and meta-regression, as well as subgroup analyses. RESULTS: Twenty-four eligible studies enrolling 4662 patients were included in this meta-analysis. According to the nature of C-MYC aberrations (gene, protein, and mRNA), studies were divided into several subgroups. For DLBCL patients with C-MYC gene abnormalities, the combined HR was 2.22 (95% confidence interval, 1.89 to 2.61) for OS and 2.29 (95% confidence interval, 1.81 to 2.90) for EFS, compared to patients without C-MYC gene abnormalities. For DLBCL patients with overexpression of C-MYC protein and C-MYC mRNA, pooled HRs for OS were 2.13 and 1.62, respectively. C-MYC aberrations appeared to play an independent role among other well-known prognostic factors in DLBCL. Addition of rituximab could not overcome the inferior prognosis conferred by C-MYC. CONCLUSION: The present systematic review and meta-analysis confirm the prognostic value of C-MYC aberrations. Screening of C-MYC should have definite prognostic meaning for DLBCL stratification, thus guaranteeing a more tailored therapy.

PAX5 alteration-associated gene-expression signatures in B-cell acute lymphoblastic leukemia.

The paired box domain gene 5 (PAX5) is frequently altered in both childhood and adult B-cell acute lymphoblastic leukemia, and takes part in leukemogenesis. We analyzed data from the database of Gene Expression Omnibus (accession number: GSE11877) using bioinformatical and statistical methods. The results showed that cases of PAX5 alteration can cluster using unsupervised clustering algorithms, and one gene, zinc and ring finger 1 (ZNRF1), was characterized and validated by quantitative RT-PCR. ZNRF1 may be associated with leukemogenesis of ALL with PAX5 alteration.

Successful engraftment of human acute lymphoblastic leukemia cells in NOD/SCID mice via intrasplenic inoculation.

Acute lymphoblastic leukemia (ALL) is a heterogeneous disorder, and primary drug resistance and relapse are thought to be the main causes for treatment failure in ALL patients. For these refractory or relapsed patients, there is an increasing demand to identify novel therapeutic approaches, which will highly rely on the use of xenotransplantation models in translational research. Given the critical role that the spleen plays in the hematopoiesis and lymphopoiesis in adult mice, intrasplenic inoculation of ALL cells into immunodeficient mice may represent a feasible route for leukemic xenotransplantation. In the present study, engraftments via intrasplenic inoculation in anti-mCD122 mAb conditioned NOD/SCID mice were achieved in 5 out of 11 cases, and the engrafted cells reconstituted a complete leukemic phenotype. The engrafted cells sustained the self-renewal capacity of leukemia-initiating cells as tested by serial xenotransplantation and can be used for evaluation of antileukemic drugs. These data suggest that the combination of intrasplenic inoculation and the targeted depletion of CD122(+) cells could provide a novel approach for the xenotransplantation of ALL cells in NOD/SCID mice. Furthermore, this model can be used for stem cell research, long-term analysis of engraftment kinetics and in vivo drug tests.

Potential application of IDH1 and IDH2 mutations as prognostic indicators in non-promyelocytic acute myeloid leukemia: a meta-analysis.

Recurrent mutations of isocitrate dehydrogenase isoforms 1 and 2 (IDH1 and IDH2) have recently been studied in adult patients with acute myeloid leukemia (AML). A meta-analysis was performed to demonstrate their controversial prognostic impacts. The associations of IDH1 or IDH2 mutations with other molecular abnormalities were also investigated. In patients with AML, IDH1/2 mutations were significantly associated with normal karyotype and isolated trisomy 8 (p < .05). After adjusting for well-studied prognostic factors, IDH1 mutation seems to be associated with subtle but significantly inferior event-free survival (EFS) (p = 0.02) and possible adverse overall survival (OS) (p = 0.13) in patients with AML, especially in the favorable genotype subset with mutated NPM1 but without FLT3-ITD mutation (p < 0.05). Longer OS (p = 0.01) and better EFS tendency (p = 0.18) are implicated in patients with IDH2 mutations, which suggests that IDH2 mutations appear to confer a favorable prognosis. Moreover, IDH1 and IDH2 mutations may play a more important role in abnormal cytogenetics subgroups such as isolated trisomy 8. Screening of IDH1/2 mutations could help to identify patients at high risk within some subsets of AML.

FLT3-ITD-associated gene-expression signatures in NPM1-mutated cytogenetically normal acute myeloid leukemia.

Concomitance of the FLT3-ITD mutation is associated with poor prognosis in NPM1-mutated cytogenetically normal acute myeloid leukemia (CN-AML) patients, and precise studies on its role in leukemogenesis are needed; these may be elucidated at the molecular level by gene express profiling. In the present study, we built a gene-expression-based classifier using prediction analysis of microarray to characterize the FLT3-ITD signature in NPM1-mutated CN-AML patients, which comprised 10 annotated genes, and demonstrated an overall accuracy of 83.8 % in cross-validation. To characterize the signature in another way, differential expression was revealed for 34 genes by class comparison, and the up-regulation of LAPTM4B and MIR155HG was validated by quantitative RT-PCR in our small cohort of NPM1-mutated CN-AML samples, which appeared to be associated with this specific subtype. The 10-gene classifier and differentially expressed genes identified in this study indicate a potential utility for risk-assessed treatment stratification, and suggest new therapeutic targets for these high-risk AML patients.