Mouse models of pediatric high-grade gliomas with MYCN amplification reveal intratumoral heterogeneity and lineage signatures.

Pediatric high-grade gliomas of the subclass MYCN (HGG-MYCN) are highly aggressive tumors frequently carrying MYCN amplifications, TP53 mutations, or both alterations. Due to their rarity, such tumors have only recently been identified as a distinct entity, and biological as well as clinical characteristics have not been addressed specifically. To gain insights into tumorigenesis and molecular profiles of these tumors, and to ultimately suggest alternative treatment options, we generated a genetically engineered mouse model by breeding hGFAP-cre::Trp53Fl/Fl::lsl-MYCN mice. All mice developed aggressive forebrain tumors early in their lifetime that mimic human HGG-MYCN regarding histology, DNA methylation, and gene expression. Single-cell RNA sequencing revealed a high intratumoral heterogeneity with neuronal and oligodendroglial lineage signatures. High-throughput drug screening using both mouse and human tumor cells finally indicated high efficacy of Doxorubicin, Irinotecan, and Etoposide as possible therapy options that children with HGG-MYCN might benefit from.

hGFAP-mediated GLI2 overexpression leads to early death and severe cerebellar malformations with rare tumor formation.

The zinc-finger transcription factor GLI2 is frequently amplified in childhood medulloblastoma of the Sonic-hedgehog type (SHH-MB), with or without amplification of NMYC or deletion of TP53. Despite the aggressive tumor behavior, tumorigenesis is not well understood, and adequate mouse models are lacking. Therefore, we generated mice with a GLI2 overexpression under control of the hGFAP-promoter. These mice died within 150 days. The majority only survived until postnatal day 40. They displayed severe cerebellar hypoplasia, cortical malformations, but no brain tumors, except for one out of 23 animals with an undifferentiated hindbrain lesion. Additional loss of p53 did not result in cerebellar tumors, but partially rescued the cerebellar phenotype induced by GLI2 overexpression. Similarly, the combination of GLI2 and NMYC was neither sufficient for the development of SHH-MB. We therefore assume that the development of childhood SHH-MB in mice is either occurring in cellular origins outside the hGFAP-positive lineage or needs additional genetic drivers.

The prognostic impact of lymphoma perforation in patients with primary gastrointestinal lymphoma - a single-center analysis.

Patients with primary gastrointestinal (GI) lymphoma are at risk of GI perforations. Therefore, we aimed to investigate the prognostic impact of non-traumatic GI perforations. 54 patients with a histologically confirmed diagnosis of primary GI lymphoma were included. Non-traumatic lymphoma perforation occurred in ten patients (19%). Perforations occurred only in patients with aggressive B-cell lymphoma. In patients with aggressive B-cell lymphoma, the median overall survival (mOS) was 52 months (95% CI 9.88-94.12) and 27 months (95% CI 0.00-135.48) in patients with and without GI perforation, respectively. The median progression-free survival (mPFS) was 30 months (95% CI 5.6-54.4) in patients with GI perforations. In patients without lymphoma perforation, mPFS was not reached. Both mOS and mPFS did not significantly differ. In conclusion, despite the need for emergency surgery and delay in lymphoma-directed treatment, lymphoma perforation did not negatively impact our study population's OS or PFS.

Single-cell transcriptomic atlas-guided development of CAR-T cells for the treatment of acute myeloid leukemia.

Chimeric antigen receptor T cells (CAR-T cells) have emerged as a powerful treatment option for individuals with B cell malignancies but have yet to achieve success in treating acute myeloid leukemia (AML) due to a lack of safe targets. Here we leveraged an atlas of publicly available RNA-sequencing data of over 500,000 single cells from 15 individuals with AML and tissue from 9 healthy individuals for prediction of target antigens that are expressed on malignant cells but lacking on healthy cells, including T cells. Aided by this high-resolution, single-cell expression approach, we computationally identify colony-stimulating factor 1 receptor and cluster of differentiation 86 as targets for CAR-T cell therapy in AML. Functional validation of these established CAR-T cells shows robust in vitro and in vivo efficacy in cell line- and human-derived AML models with minimal off-target toxicity toward relevant healthy human tissues. This provides a strong rationale for further clinical development.

Abdominal emergency surgery in patients with hematological malignancies: a retrospective single-center analysis.

BACKGROUND: Hematologic patients requiring abdominal emergency surgery are considered to be a high-risk population based on disease- and treatment-related immunosuppression. However, the optimal surgical therapy and perioperative management of patients with abdominal emergency surgery in patients with coexisting hematological malignancies remain unclear. METHODS: We here report a single-center retrospective analysis aimed to investigate the impact of abdominal emergency surgery due to clinically suspected gastrointestinal perforation (group A), intestinal obstruction (group B), or acute cholecystitis (group C) on mortality and morbidity of patients with coexisting hematological malignancies. All patients included in this retrospective single-center study were identified by screening for the ICD 10 diagnostic codes for gastrointestinal perforation, intestinal obstruction, and ischemia and acute cholecystitis. In addition, a keyword search was performed in the database of all pathology reports in the given time frame. RESULTS: A total of 56 patients were included in this study. Gastrointestinal perforation and intestinal obstruction occurred in 26 and 13 patients, respectively. Of those, 21 patients received a primary gastrointestinal anastomosis, and anastomotic leakage (AL) occurred in 33.3% and resulted in an AL-related 30-day mortality rate of 80%. The only factor associated with higher rates of AL was sepsis before surgery. In patients with suspected acute cholecystitis, postoperative bleeding events requiring abdominal packing occurred in three patients and lead to overall perioperative morbidity of 17.6% and surgery-related 30-day mortality of 5.9%. CONCLUSION: In patients with known or suspected hematologic malignancies who require emergency abdominal surgery due to gastrointestinal perforation or intestinal obstruction, a temporary or permanent stoma might be preferred to a primary intestinal anastomosis.

Molecular response patterns in relapsed/refractory AML patients treated with selinexor and chemotherapy.

Relapse in patients with acute myeloid leukemia (AML) is common and is associated with a dismal prognosis. Treatment options are limited and the understanding of molecular response patterns is still challenging. We analyzed the clonal response patterns of 15 patients with relapsed/refractory AML treated with selinexor in a phase II trial (SAIL). DNA was analyzed at three time points and showed a decline of mutated alleles in FLT3, SF3B1, and TP53 under SAIL treatment. Overall survival (OS) was similar between patients with declining versus persisting clones. We show an interesting long-term course of a patient who relapsed after allogeneic stem cell transplantation (alloHCT) with SF3B1- and SRSF2-mutated AML and received selinexor as maintenance treatment for 4 years. Measurable residual disease (MRD) remained detectable for 2 weeks after donor lymphocyte infusion (DLI) in this patient and then remained negative under selinexor maintenance treatment. Selinexor was tolerated well and was stopped after 4 years of SAIL treatment. We present an exploratory study and identify subclonal patterns of patients treated with selinexor.

COVID-19 and Adult Acute Leukemia: Our Knowledge in Progress.

The majority of publications regarding SARS-CoV-2 infections in adult patients with acute leukemia (AL) refer to hematological patients in general and are not focused on acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). We herein report a review of the current literature on adult AL patients infected with SARS-CoV-2. Overall, SARS-CoV-2-associated mortality ranges from 20-52% in patients with adult AL. AML patients have a particularly high COVID-19-related mortality. Of note, most of the available data relate to the pre-vaccination era and to variants before Omicron. The impact of COVID-19 infections on AL treatment is rarely reported. Based on the few studies available, treatment delay does not appear to be associated with an increased risk of relapse, whereas therapy discontinuation was associated with worse outcomes in AML patients. Therefore, the current recommendations suggest delaying systemic AL treatment in SARS-CoV-2-positive patients until SARS-CoV-2 negativity, if immediate AL treatment is not required. It is recommended to offer vaccination to all AL patients; the reported antibody responses are around 80-96%. Seronegative patients should additionally receive prophylactic administration of anti-SARS-CoV-2 monoclonal antibodies. Patients with AL infected with SARS-CoV-2 should be treated early with antiviral therapy to prevent disease progression and enable the rapid elimination of the virus.

Retrospective analysis of three induction chemotherapy regimens in acute myeloid leukemia including CPX-351, cytarabine/daunorubicin with and without the addition of cladribine.

Recently new treatments for acute myeloid leukemia (AML) emerged, including regimens like CPX-351 and cladribine with cytarabine and daunorubicin (DA + C), demonstrating improved survival in patient subsets. This retrospective analysis is comparing the outcome of 124 patients treated with cytarabine and daunorubicin (DA; n = 54), CPX-351 (n = 26) and DA + C (n = 44). Complete response rate following one cycle of therapy was increased in DA + C (62%) compared to CPX-351 (42%) and DA (50%). CPX-351 demonstrated a significant increased survival post allogenic stem cell transplantation against DA (hazard ratio (HR): 4.9; 95% confidence interval (95%CI): 1.1-21, p = 0.03). Median survival was reached for DA (5.6 years) but not for DA + C or CPX-351. Subgroup analysis showed that AML with myelodysplasia-related changes and therapy-related AML treated with CPX-351 had increased survival compared to DA (HR: 5.2; 95%CI: 1.2-22; p = 0.03). Our findings point twoards a CPX-351 superiority. However, the use of DA + C should be further evaluated in comparative studies.

Clinical features of hepatitis E infections in patients with hematologic disorders.

Hepatitis E virus is increasingly being reported to cause chronic infection in immunocompromised patients. However, less is known about patients with an underlying hematologic disease. In particular, the impact of hepatitis E infection on oncological therapy has been poorly described. In this retrospective single-center study, we analyzed 35 hematologic patients with hepatitis E, including 20 patients under active oncological treatment and 15 patients who were in the posttreatment follow-up or under active surveillance. The primary aim was to describe the clinical courses with particular focus on any hepatitis E-related therapy modifications of cancer-directed therapy. In the majority (60%) of patients who were under active oncological treatment, hepatitis E-related therapy modifications were made, and 25% of deaths were due to progression of the hematologic disease. In patients receiving concomitant oncological treatment, no hepatitis Erelated deaths occurred. In contrast, two patients in the follow-up group died from hepatitis E-associated acute-onchronic liver failure. Chronic hepatitis E was observed in 34% of all cases and 43% received ribavirin therapy; of those, 27% achieved a sustained virological response. CD20-directed therapy was the only independent risk factor for developing chronic hepatitis E. We conclude that CD20-directed treatment at any time point is a risk factor for developing chronic hepatitis E. Nevertheless, since mortality from the progression of hematologic disease was higher than hepatitis E-related mortality, we suggest careful case-by-case decisions on modifications of cancer treatment. Patients in the posttreatment follow-up phase may also suffer from severe courses and hepatitis E chronicity occurs as frequently as in patients undergoing active therapy.

Diagnostic Utility of Bronchoalveolar Lavage in Patients with Acute Leukemia under Broad-Spectrum Anti-Infective Treatment.

Despite therapeutic advances in the prevention and treatment of febrile neutropenia, acute leukemia (AL) patients still have considerable febrile neutropenia-related mortality. However, the diagnostic yield of flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) in acute leukemia patients is unclear. In this retrospective single-center study, we analyzed 88 BAL samples of patients with acute leukemia and pulmonary infiltrates in spite of treatment with broad-spectrum anti-infective agents. The aim was to investigate the impact of FB with BAL on detecting causative organisms, which would result in a change in treatment regimens. The median age was 59 years, and 86% had acute myeloid leukemia. In 47%, pathogens were detectable in BAL fluid (pathogen bacteria, viruses, and fungi in 2, 15, and 18%, respectively), with Aspergillus fumigatus detected most frequently. BAL-guided anti-infective therapy changes were performed in 15%. The detection of herpes simplex and influenza viruses were the main reasons for treatment changes. Despite broad-spectrum anti-infective treatment, in approximately half of all patients, pathogens could still be isolated in BAL samples. However, consecutive changes in anti-infective treatment were considerably less frequent, with most changes performed in patients with Herpes simplex virus and Influenza A detection. The need for FB with BAL in patients with AL receiving broad-spectrum empiric anti-infective treatment should therefore be weighed carefully.

Efficacy of Tigecycline as Salvage Therapy in Multidrug-Resistant Febrile Neutropenia in Patients with Acute Leukemia-A Single Center Analysis.

Severe infectious complications remain the main cause of mortality in leukemia patients due to a long period of profound neutropenia. Standardized regimens for antimicrobial, antifungal, and antiviral prophylaxis and therapy in neutropenic patients have improved infection-associated mortality. Nevertheless, many patients are refractory to these multidrug approaches. Tigecycline is a last-resort antibiotic with a broad-spectrum activity; unfortunately, clinical experience in multidrug-resistant febrile neutropenia is limited. The aim was to evaluate the efficacy of tigecycline treatment in comparison to standard treatment in this patient cohort. In this single center analysis, we analyzed the clinical courses of 73 patients with acute leukemia and diagnosis of febrile neutropenia resistant to hospital-based multidrug escalation levels who continued on a standard approach without antibiotics as the last resort (n = 30) or were switched to tigecycline in addition to carbapenem treatment (n = 43). We observed comparable overall response rates (decrease in C-reactive protein or resolution of fever) in both patient cohorts. Switching the antibiotic approach to tigecycline showed lower absolute sepsis (33% vs. 47%, p = 0.235) and infection-associated mortality rates (5% vs. 13%, p = 0.221). Prospective larger randomized studies are necessary to underline these results and to be able to generate reliable statistics.

COVID-19 and seasonal influenza: a comparative analysis in patients with hematological malignancies.

The severity and mortality of COVID-19 and seasonal influenza were recently compared in the general population but not in patients with hematological malignancies. We analyzed the clinical courses of 79 patients with hematological malignancies and diagnosis of either SARS-CoV-2 (n = 29) or influenza A or B infections (n = 50) who were admitted or were already under treatment in the Department of Oncology, Hematology and Stem cell Transplantation at the University Medical Center Hamburg-Eppendorf, Germany, between 1 January 2012 and 31 January 2021. For COVID-19, we observed significantly higher rates of acute respiratory distress syndrome with 48% (14/29) compared to 14% (7/50) in the influenza group (p = 0.001) as well as a significantly higher virus-associated 90-day mortality (41% vs. 12%, p = 0.005). Based on our results, we conclude that infections with SARS-CoV-2 are more severe than influenza A or B in patients with hematological malignancies.

Mebendazole Mediates Proteasomal Degradation of GLI Transcription Factors in Acute Myeloid Leukemia.

The prognosis of elderly AML patients is still poor due to chemotherapy resistance. The Hedgehog (HH) pathway is important for leukemic transformation because of aberrant activation of GLI transcription factors. MBZ is a well-tolerated anthelmintic that exhibits strong antitumor effects. Herein, we show that MBZ induced strong, dose-dependent anti-leukemic effects on AML cells, including the sensitization of AML cells to chemotherapy with cytarabine. MBZ strongly reduced intracellular protein levels of GLI1/GLI2 transcription factors. Consequently, MBZ reduced the GLI promoter activity as observed in luciferase-based reporter assays in AML cell lines. Further analysis revealed that MBZ mediates its anti-leukemic effects by promoting the proteasomal degradation of GLI transcription factors via inhibition of HSP70/90 chaperone activity. Extensive molecular dynamics simulations were performed on the MBZ-HSP90 complex, showing a stable binding interaction at the ATP binding site. Importantly, two patients with refractory AML were treated with MBZ in an off-label setting and MBZ effectively reduced the GLI signaling activity in a modified plasma inhibitory assay, resulting in a decrease in peripheral blood blast counts in one patient. Our data prove that MBZ is an effective GLI inhibitor that should be evaluated in combination to conventional chemotherapy in the clinical setting.

The BET bromodomain inhibitor ZEN-3365 targets the Hedgehog signaling pathway in acute myeloid leukemia.

Modern cancer therapies increased the survival rates of acute myeloid leukemia (AML) patients tremendously. However, the complexity of the disease and the identification of new targets require the adaptation of treatment protocols to reduce side effects and increase benefit for the patients. One key regulator of leukemogenesis and chemotherapy resistance in AML is the Hedgehog (HH) signaling pathway. It is deregulated in numerous cancer entities and inhibition of its downstream transcription factors GLI translates into anti-leukemic effects. One major regulator of GLI is BRD4, a BET family member with epigenetic functions. We investigated the effect of ZEN-3365, a novel BRD4 inhibitor, on AML cells in regard to the HH pathway. We show that ZEN-3365 alone or in combination with GANT-61 reduced GLI promoter activity, cell proliferation and colony formation in AML cell lines and primary cells. Our findings strongly support the evaluation of the BRD4 inhibitor ZEN-3365 as a new therapeutic option in AML.

Ruxolitinib plus extracorporeal photopheresis (ECP) for steroid refractory acute graft-versus-host disease of lower GI-tract after allogeneic stem cell transplantation leads to increased regulatory T cell level.

Acute graft-versus-host disease (aGVHD) is a serious complication after stem cell transplantation and is associated with high non-relapse mortality. If steroid treatment as first-line therapeutic approach fails, treatment options are limited. In retrospective studies, ruxolitinib, a selective Janus kinase 1/2 inhibitor as well as extracorporeal photopheresis (ECP) could show high efficacy in treatment of steroid refractory acute and chronic GVHD. Here, we report single-center experience of combining JAK-inhibitor treatment with ECP in 18 patients with severe steroid refractory aGVHD of lower GI-tract. The treatment was well tolerated and no severe cytopenia (grade IV) occurred, in three patients grade III cytopenia could be observed. Response was complete or partial in 44% and 11%, respectively, resulting in an estimated 2 year overall survival of 56%. Steroids were tapered rapidly with a median time of 2 days for halving of dosage avoiding additional steroid-associated side effects. Under treatment with ruxolitinib and ECP, an increased level of regulatory T cells could be observed elucidating direct effects of this treatment on immune response.