Comprehensive analysis of MYB/MYBL1-altered pediatric-type diffuse low-grade glioma.

BACKGROUND: Pediatric-type diffuse low-grade gliomas (pLGG) harboring recurrent genetic alterations involving MYB or MYBL1 are closely related tumors. Detailed treatment and outcome data of large cohorts are still limited. This study aimed to comprehensively evaluate pLGG with these alterations to define optimal therapeutic strategies. METHODS: We retrospectively reviewed details of pLGG with MYB or MYBL1 alterations from patients treated or referred for pathologic review at St. Jude Children's Research Hospital. Tumor specimens were centrally reviewed, and clinical data were collated. RESULTS: Thirty-three patients (18 male; median age, 5 years) were identified. Two tumors had MYBL1 alterations; 31 had MYB alterations, MYB::QKI fusion being the most common (n = 10, 30%). Most tumors were in the cerebral hemispheres (n = 22, 67%). Two patients (6%) had metastasis at diagnosis. The median follow-up was 6.1 years. The 5-year event-free survival (EFS) rate was 81.3% ±â€…8.3%; the 5-year overall survival (OS) rate was 96.4% ±â€…4.1%. Patients receiving a near-total or gross-total resection had a 5-year EFS of 100%; those receiving a biopsy or subtotal resection had a 5-year EFS rate of 56.6% ±â€…15.2% (P < .01). No difference in EFS was observed based on location, histology, or molecular alterations. However, the tumors that progressed or metastasized may have distinct methylation profiles with evidence of activation of the MAPK and PI3K/AKT/mTOR pathways. CONCLUSIONS: pLGG with MYB/MYBL1 alterations have good outcomes. Our findings suggest that surgical resectability is a crucial determinant of EFS. Further characterization is required to identify optimal treatment strategies for progressive tumors.

Retrospective analysis of outcomes for pediatric acute lymphoblastic leukemia in South American centers.

Introduction: Acute lymphoblastic Leukemia (ALL) is the most common pediatric malignancy. While the survival rate for childhood ALL exceeds 90% in high-income countries, the estimated survival in low-and middle-income countries ranges from 22-79%, depending on the region and local resources. Methods: This study retrospectively reviewed demographic, biological, and clinical parameters of children under 18 years of age with newly diagnosed ALL presenting between 2013-2017 across five pediatric centers in 4 countries in South America. Survival analyses were estimated using the Kaplan-Meier method. Results: Across the five centers, 752 patients were analyzed (Bolivia [N=9], Ecuador [N=221], Paraguay [N=197], Peru [N=325]) and 92.1% (n=690) patients were diagnosed with B-cell and 7.5% (n= 56) with T-cell ALL. The median age was 5.5 years old (IQR 7.29). At diagnosis, 47.8% of patients were categorized as standard and 51.9% as high risk per their institutional regimen. Advanced diagnostics availability varied between modalities. MRD was evaluated in 69.1% of patients; molecular testing was available for ETV6-RUNX, BCR-ABL1, TCF3-PBX1, and KMT2A-rearranged ALL in 75-81% of patients; however, karyotyping and evaluation for iAMP21 were only performed in 42-61% of patients. Central nervous system (CNS) involvement was evaluated at diagnosis in 57.3% (n=429) patients; of these, 93.7% (n=402) were CNS 1, 1.6% (n=7) were CNS 2, 0.7% (n=11) were CNS3, 1.9% (n=8) had cranial nerve palsy, and 2.1% (n=9) results unavailable. Chemotherapy delays >2 weeks were reported in 56.0% (n=421) patients during treatment. Delays were attributed to infection in 63.2% (n=265), drug-related toxicities in 47.3% (n=198), and resource constraints, including lack of bed availability in 23.2% (n=97) of patients. The 3-year Abandonment-sensitive EFS and OS were 61.0±1.9% and 67.2±1.8%, respectively. The 3-year EFS and OS were 71.0±1.8% and 79.6±1.7%, respectively. Discussion: This work reveals opportunities to improve survival, including addressing severe infections, treatment interruptions, and modifications due to drug shortages. In 2018, healthcare professionals across South America established the Pediatric Oncology Latin America (POLA) group in collaboration with St. Jude Children's Research Hospital. POLA collaborators developed an evidence-based, consensus-derived, adapted treatment guideline, informed by preliminary results of this evaluation, to serve as the new standard of care for pediatric ALL in participating institutions.

Evaluation of factors leading to poor outcomes for pediatric acute lymphoblastic leukemia in Mexico: a multi-institutional report of 2,116 patients.

Background and aims: Pediatric acute lymphoblastic leukemia (ALL) survival rates in low- and middle-income countries are lower due to deficiencies in multilevel factors, including access to timely diagnosis, risk-stratified therapy, and comprehensive supportive care. This retrospective study aimed to analyze outcomes for pediatric ALL at 16 centers in Mexico. Methods: Patients <18 years of age with newly diagnosed B- and T-cell ALL treated between January 2011 and December 2019 were included. Clinical and biological characteristics and their association with outcomes were examined. Results: Overall, 2,116 patients with a median age of 6.3 years were included. B-cell immunophenotype was identified in 1,889 (89.3%) patients. The median white blood cells at diagnosis were 11.2.5 × 103/mm3. CNS-1 status was reported in 1,810 (85.5%), CNS-2 in 67 (3.2%), and CNS-3 in 61 (2.9%). A total of 1,488 patients (70.4%) were classified as high-risk at diagnosis. However, in 52.5% (991/1,889) of patients with B-cell ALL, the reported risk group did not match the calculated risk group allocation based on National Cancer Institute (NCI) criteria. Fluorescence in situ hybridization (FISH) and PCR tests were performed for 407 (19.2%) and 736 (34.8%) patients, respectively. Minimal residual disease (MRD) during induction was performed in 1,158 patients (54.7%). The median follow-up was 3.7 years. During induction, 191 patients died (9.1%), and 45 patients (2.1%) experienced induction failure. A total of 365 deaths (17.3%) occurred, including 174 deaths after remission. Six percent (176) of patients abandoned treatment. The 5-year event-free survival (EFS) was 58.9% ± 1.7% for B-cell ALL and 47.4% ± 5.9% for T-cell ALL, while the 5-year overall survival (OS) was 67.5% ± 1.6% for B-cell ALL and 54.3% ± 0.6% for T-cell ALL. The 5-year cumulative incidence of central nervous system (CNS) relapse was 5.5% ± 0.6%. For the whole cohort, significantly higher outcomes were seen for patients aged 1-10 years, with DNA index >0.9, with hyperdiploid ALL, and without substantial treatment modifications. In multivariable analyses, age and Day 15 MRD continued to have a significant effect on EFS. Conclusion: Outcomes in this multi-institutional cohort describe poor outcomes, influenced by incomplete and inconsistent risk stratification, early toxic death, high on-treatment mortality, and high CNS relapse rate. Adopting comprehensive risk-stratification strategies, evidence-informed de-intensification for favorable-risk patients and optimized supportive care could improve outcomes.

Physician Perceptions of and Barriers to Pediatric Palliative Care for Children With Cancer in Brazil.

PURPOSE: Early integration of pediatric palliative care (PPC) for children with cancer is critical to improving the quality of life of both the patient and family. Understanding physician perceptions of palliative care and perceived barriers to early integration is necessary to develop PPC in Brazil. METHODS: The Assessing Doctors' Attitudes on Palliative Treatment survey was modified for use in Brazil. The survey was open from January 2022 to June 2022 and distributed to physicians of all specialties from participating institutions who treat children with cancer. Statistical analysis was complemented by qualitative analysis of open-ended responses. RESULTS: A total of 272 respondents participated. Most respondents reported access to PPC experts for consultation (77.2%) and 34.5% indicated previous palliative care training. Physician knowledge of PPC was generally aligned with WHO guidance (median alignment, 93.0%; range, 80.5%-98.2%). However, about half (53.3%) felt comfortable addressing physical needs of patients receiving PPC, 35.3% addressing emotional needs, 25.8% addressing spiritual needs, and 33.5% addressing grief and bereavement needs. Most respondents (65.4%) felt palliative care should be involved from diagnosis, but only 10.3% stated that this occurred in their setting. The most important barriers identified were physician discomfort (89.0%), limited physician knowledge (88.6%), and lack of home-based services (83.8%). CONCLUSION: Despite a strong understanding of the role of palliative care, physicians in Brazil reported low confidence delivering PPC to children with cancer. Additionally, physicians generally believed that PPC should be integrated earlier in the disease trajectory of children with cancer. This work will direct educational and capacity building initiatives to ensure greater access to high-quality PPC for children with cancer in Brazil to address patient and family suffering.

Overexpression of activation-induced cytidine deaminase in B cells is associated with production of highly pathogenic autoantibodies.

Defective receptor editing or defective B cell checkpoints have been associated with increased frequency of multireactive autoantibodies in autoimmune disease. However, Ig somatic hypermutation and/or class switch recombination may be mechanisms enabling the development of pathogenic multireactive autoantibodies. In this study, we report that, in the BXD2 mouse model of autoimmune disease, elevated expression of activation-induced cytidine deaminase (AID) in recirculating follicular CD86(+) subsets of B cells and increased germinal center B cell activity are associated with the production of pathogenic multireactive autoantibodies. CD4 T cells from BXD2 mice that expressed increased levels of CD28 and an increased proliferative response to anti-CD3 and anti-CD28 stimulation are required for this process. Inhibition of the CD28-CD86 interaction in BXD2 mice with AdCTLA4-Ig resulted in normalization of AID in the B cells and suppression of IgG autoantibodies. This treatment also prevented the development of germinal center autoantibody-producing B cells, suggesting that an optimal microenvironment enabling AID function is important for the formation of pathogenic autoantibodies. Taken together, our data indicate that AID expression in B cells is a promising therapeutic target for the treatment of autoimmune diseases and that suppression of this gene may be a molecular target of CTLA4-Ig therapy.

Chlamydia pneumoniae infected macrophages exhibit enhanced plasma membrane fluidity and show increased adherence to endothelial cells.

Chlamydia pneumoniae, an intracellular prokaryote, is known to have requirement for some lipids which it is incapable of synthesizing, and these lipids have important fluidizing roles in plasma membrane. We decided to examine if the trafficking of these lipids to C. pneumoniae alters the physicochemical properties of macrophage plasma membrane, affects the expression of genes and proteins of enzymes associated with metabolism of some of these lipids and assess if Ca2+ signaling usually induced in macrophages infected with C. pneumoniae modulates the genes of these selected enzymes. Chlamydia pneumoniae induced the depletion of macrophage membrane cholesterol, phosphatidylinositol and cardiolipin but caused an increase in phosphotidylcholine resulting in a relative increase in total phospholipids. There was increased membrane fluidity, enhanced macrophage fragility and heightened adherence of macrophages to endothelial cells despite the application of inhibitor of adhesion molecules. Also, there was impairment of macrophage 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase gene and protein expression independent of Ca2+ signaling, while phospholipase C gene and protein were up-regulated in a manner minimally dependent on Ca2+ signaling. The implications of these findings are that macrophages infected with C. pneumoniae have altered membrane physicochemical characteristics which may render them atherogenic.

Elicitation of reactive oxygen species in Chlamydia pneumoniae-stimulated macrophages: a Ca2+-dependent process involving simultaneous activation of NADPH oxidase and cytochrome oxidase genes.

Chlamydia pneumoniae, a respiratory pathogen implicated in the development and progress of atherosclerosis, is known to infect and survive in macrophages, despite macrophage producing reactive oxygen species (ROS). To gain insight into ROS generation in macrophages infected with C. pneumoniae and to explore factors accounting for their final levels and effect, we investigated the role of NADPH oxidase and cytochrome oxidase pathways in the production and modulation of ROS. We also determined the operational role of Ca2+ signaling in the process. Macrophages stimulated with C. pneumoniae exhibit early release of ROS via up-regulation of NADPH oxidase and cytochrome c oxidase activities. Increasing the dose of C. pneumoniae led to an increase in the expression of these enzymes gene production, which was accompanied by a significant up-regulation of their gene products, implying a probable activation of transcriptional and translational processes, respectively. The change in levels of free Ca2+, influx across plasma membrane and efflux from intracellular store into cytosol all exhibited a significant regulatory role on the ROS generation pathways in macrophages. The observed events were shown to be dependent on binding of C. pneumoniae to CD14 receptors of macrophages. The data reported here imply that macrophages infected with C. pneumoniae produce ROS through membrane-associated NADPH oxidase with oxidative phosphorylation levels depending on Ca2+ influx signals.

Induction of lipoprotein lipase gene expression in Chlamydia pneumoniae-infected macrophages is dependent on Ca2+ signaling events.

Unregulated uptake of low density lipoprotein (LDL) in macrophages is the hallmark of early atherogenic lesions, and Chlamydia pneumoniae infection of macrophages induces this process by an unknown mechanism. It was therefore aimed in this study to investigate (i) the role of C. pneumoniae in macrophage expression of the lipoprotein lipase (LpL) gene, (ii) the probable role of Ca2+ influx signals and (iii) the effect of the process on LDL uptake. Lipoprotein lipase mRNA expression and LpL activity in infected RAW-264.7 cells were significantly upregulated. A biphasic Ca2+ influx signal was observed in infected cells with a moderate influx (303 nM Ca2+) favoring optimal LpL gene expression. Also, the antagonists of L-type Ca2+ channel in macrophages significantly down-regulated LpL gene expression and the biomolecular content of C. pneumoniae responsible for the observed events was in part found to be Chlamydia lipopolysaccharide (cLPS). Investigations aimed at determining the specific relevance of Ca(2+)-dependent lipoprotein lipase gene expression in C. pneumoniae-infected macrophages showed that the condition caused enhanced uptake of LDL which was abrogated by Calphostin-C-mediated down-regulation of LpL. This discovery of a specialized Ca2+ influx signal-mediated LpL upregulation in C. pneumoniae-infected macrophages provides a mechanistic insight into early events involving C. pneumoniae in macrophage foam cell formation resulting from LDL uptake.