Search Results (503)

KMT2A-rearranged (KMT2A-r) acute lymphoblastic leukemia (ALL), particularly in infants, represents one of the most aggressive pediatric hematological malignancies with a historically dismal prognosis. While KMT2A-AFF1 (t(4;11)) is the most prevalent fusion, a diverse array of partner genes exists, each conferring distinct biological and clinical features. This review focuses on the rare but clinically significant KMT2A-AFF3 subtype, which arises from the t(2;11)(q11.2;q23) chromosomal translocation. This review summarizes the molecular pathogenesis driven by the KMT2A-AFF3 fusion oncoprotein, which functions as an aberrant transcriptional complex. This complex hijacks essential epigenetic machinery, including the recruitment of DOT1L and interaction with Menin, leading to pathogenic histone modifications (e.g., H3K79 hypermethylation) and the subsequent upregulation of critical target genes, notably the HOXA cluster and MEIS1, thereby enforcing a B-lymphoid differentiation arrest at the pro-B/pre-B stage. Clinically, KMT2A-AFF3 ALL is characterized by high-risk features, including infant onset, hyperleukocytosis, central nervous system (CNS) involvement, and a distinct CD10-negative immunophenotype. This review highlights the evidence defining its poor prognosis, which is primarily driven by profound chemoresistance to conventional therapies, including glucocorticoids. Finally, we discuss the rapidly evolving therapeutic landscape, detailing the limitations of standard intensive chemotherapy and the immense promise of novel targeted strategies, such as Menin inhibitors (e.g., Revumenib), DOT1L inhibitors, and immunotherapies (e.g., CAR-T cells, Blinatumomab), which hold the potential to revolutionize outcomes for this high-risk leukemia subtype. Full article

Studies of the genomic stability of Ewing sarcoma (EwS) have produced contradictory findings. While they are generally characterized by low mutation rates of individual genes, several cases exhibit genomic alterations that manifest as chromosomal gains and losses. Taken together, these alterations represent independent biomarkers for EwS, such as loss of heterozygosity (LOH) or an altered genome. Patients with primary EwS tumors with fewer than three copy number alterations (CNAs) have a better prognosis than those with more CNAs. The functional mechanisms underlying this chromosomal instability are not yet clear. However, there are indications that this may be directly caused by the EWSR1::ETS translocations that are characteristic of EwS. The transcriptional behavior of the chimeric transcription factor EWSR1-FLI1 leads to the formation of R-loop DNA–RNA hybrids that form when RNA binds back to DNA during transcription and increased replication stress, which may result in structural chromosomal changes. Additionally, the formation of EWSR1 fusion genes in EwS results in the loss of one or both wild-type EWSR1 alleles in sarcoma cells. As chromosome segregation has been observed under loss of wild-type EWSR1, EWSR1 loss has been proposed as a potential source of LOH. So, it is highly probable that a chromosomal translocation and the subsequent formation of the EWSR1-ETS fusion protein cause the genomic alterations in EwS. This indicates that targeted therapy should be directed against the CNA and LOH biology caused by the fusion protein. Full article

Background: Ewing sarcoma (ES) is a rare tumor that affects children, adolescents, and young adults. ES is associated with high morbidity in all patients and high mortality for those who present with metastatic disease. A chromosomal translocation, either t(11;22)(q24;p12) or t(21;22)(q22;q12) leads to the fusion oncoproteins EWS::FLI1 or EWS::ERG in 95% of ES patients. We recognized a critical need for a stably sourced high-affinity antibody that recognizes EWS::FLI1 with maximal specificity. Understanding EWS::FLI1 protein complexes is a pivotal gap in ES knowledge that necessitates the development of antibodies capable of identifying native proteins in solution. Further, variable epitope sequencing of a monoclonal antibody enables the construction of degraders and nanobody identifiers. Methods: Monoclonal antibodies were produced following informed peptide synthesis, injection, and hybridoma creation. Hybridoma antibodies were validated for specificity and function. Results: Our results indicate that the FLI1 1.2 monoclonal antibody, which recognizes the EWS::FLI1 fusion oncoprotein, can be reliably applied to multiple molecular biology applications like immunoblot, immunoprecipitation, immunofluorescence, and immunohistochemistry. This FLI1 1.2 monoclonal antibody has a high affinity of 0.3 nM KD to EWS::FLI1. In terms of specificity, this antibody is highly specific to EWS::FLI1 and some cross reactivity with ERG. Conclusions: This reagent will provide the research community with valuable tools for further biochemical and genomic interrogation of the oncogenic activity of EWS::FLI1 in ES. Full article

Undifferentiated pleomorphic sarcoma (UPS) is the most morphologically and genetically heterogeneous form of soft tissue sarcoma. UPS tumors can exhibit a wide range of genetic abnormalities, including activating and inactivating mutations, gene amplifications, chromosomal translocations, and copy number variations. Owing to this extensive genetic heterogeneity, no UPS-specific therapeutic targets have yet been validated, complicating diagnosis, prognosis, and the selection of targeted treatment strategies. Currently, immune checkpoint inhibitors (targeting PD-1, PD-L1, and CTLA-4) are the only validated targeted therapy for UPS, reflecting the frequent mutational events that activate immune response pathways. Because molecular genetic profiling alone provides limited prognostic value for chemoresistance in UPS, the development of experimental ex vivo and in vitro testing approaches may help to identify and exclude potentially ineffective targeted therapies. Full article

Acute myeloid leukemia (AML) is an aggressive clonal hematopoietic malignancy, characterized by marked biological heterogeneity and variable clinical outcomes. Among its rarer genetic subsets is AML with rearrangements of the MDS1 and EVI1 complex locus (MECOM), occurring in fewer than 2% of newly diagnosed cases. This review examines the biology and clinical significance of MECOM-rearranged AML, with a focus on its diverse mechanisms of leukemogenesis, including chromosomal inversion and translocation involving 3q26. We discuss how aberrant EVI1/MECOM activity alters gene expression networks and drives malignant transformation. Current therapeutic approaches—including intensive chemotherapy, hypomethylating agents in combination with venetoclax, and allogeneic stem cell transplantation—are evaluated with particular emphasis on inv(3) and other t(3q26) subtypes. Despite these treatment strategies, outcomes remain poor, underscoring the urgent need for novel, more effective therapies for this high-risk form of AML. Full article

Pre-B-cell leukemia factor 1 (PBX1) is a transcription factor that plays a significant role in various physiological, developmental, and oncogenic processes in humans. The mechanisms and interactions of PBX1 in both solid and hematologic malignancies remain significant areas of study. It was initially found in pre-B-cell acute lymphoblastic leukemia as a result of the chromosomal translocation t(1;19). Over the years, its role in other blood neoplasms has been studied. PBX1 and its variant E2A::PBX1 regulate gene expression that influences cell proliferation and differentiation in hematopoietic lineages. Their interaction with oncogenic partners results in abnormal gene regulation and tumorigenesis. Research has predominantly focused on the role of these factors in leukemias and plasma cell neoplasms, whereas other hematologic neoplasms have been largely overlooked. The potential application of PBX1 as a prognostic and predictive biomarker has recently gained attention. However, further research is needed to fully understand its complex role and how it can be targeted for therapeutic purposes. This review summarizes current knowledge on PBX1’s role in the growth of both mature and immature hematologic neoplasms. Moreover, it focuses on its prospective use as a therapeutic target and to predict prognosis, especially for aggressive neoplasms that do not respond to current therapeutic approaches. Full article

Childhood cancer is rare, with about 1 in 260 children developing cancer before age 20. However, it remains a leading cause of death for children and adolescents worldwide. The 5-year survival rate for childhood cancer in high-income countries exceeds 80%, but globally, the average survival rate is around 37%, highlighting significant disparities across the globe. Despite the life-saving impact of current treatment regimens, long-term side effects and risks are always concerns. Therefore, there is a continuing urgent need for novel therapies to overcome the limitations of existing approaches and improve patient outcomes. Targeted drug therapies that interfere with cancer-causing genes play a vital role in cancer treatment by specifically targeting cancer cells. TFs are primary drivers of gene expression that are critical in various pediatric cancers. Chromosomal rearrangements, involving changes in chromosome structure such as deletions, duplications, inversions, and translocations, can significantly alter TF activity and downstream gene expression. Dysregulation of TFs disrupts gene expression networks and has been strongly linked to the development and progression of many pediatric cancers, making them promising therapeutic targets. Several approaches targeting TFs, including small-molecule inhibitors designed to block TF-DNA binding, TF-cofactor interactions, or their epigenetic regulation, as well as RNA interference, have been developed. More recently, approaches like PROTACs (Proteolysis-Targeting Chimeras) and molecular glue degraders offer new therapeutic possibilities in pediatric cancers. These innovations represent a paradigm shift in pediatric oncology, offering hope for more targeted, less toxic treatment options. This review discusses the critical role of TFs in childhood cancers and emphasizes the need for evolving therapeutic strategies aimed at targeting these key regulators to improve outcomes for young patients. Full article

Jumping translocations (JTs) can lead to partial trisomies. A breakpoint within the gene known as Jumping Translocation Breakpoint (JTB) has previously been associated with JTs involving the long arm of human chromosome 1 (1q). These 1q+ amplifications are frequently observed in cancer. JTB was initially mapped to the Epidermal Differentiation Complex (EDC) at 1q21, and earlier studies primarily focused on its role in malignant or adult tissues. Using updated genomic data, we refined the mapping of JTB. We employed RNA in situ hybridization (RISH) to visualize Jtb expression with organ, tissue, and cell-level resolution. We demonstrate that human JTB and murine Jtb are located outside the EDC. In midgestational wild-type mouse embryos, Jtb is expressed in multiple tissues, including the developing heart and vertebral column, and shows partial overlap with the expression of early markers of the neural crest cell lineage. Our findings suggest that the oncogenic potential associated with human JTB translocations is likely unrelated to its previously assumed location within the EDC. Full article

Cancer is a multifaceted disease characterized by uncontrolled cell division resulting from substantial disruptions of normal biological processes. Central to its development is cellular transformation, which involves a dynamic sequence of events including chromosomal translocations, genetic mutations, abnormal DNA methylation, post-translational protein modifications, and other genetic and epigenetic alterations. These changes compromise physiological regulatory mechanisms and contribute to accelerated tumor growth. A critical factor in this process is the dysregulation of transcription factors (TFs) which regulate gene expression and DNA transcription. Dysregulation of TFs initiates a cascade of biochemical events, such as abnormal DNA replication, that further enhance cell proliferation and increase genomic instability. This microenvironment not only sustains tumor growth but also promotes the accumulation of somatic mutations, thereby fueling tumor evolution and heterogeneity. In this study, we employed an in silico approach to identify TFs regulating 622 key genes whose mutations are implicated in carcinogenesis. Transcriptional regulatory networks were analyzed through bioinformatics methods to elucidate molecular pathways involved in cancer development. A thorough understanding of these processes may help to clarify the function of dysregulated TFs and facilitate the development of novel therapeutic approaches designed to make cancer treatments personalized and efficacious. Full article

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disorder characterized by progressive demyelination and axonal degeneration within the central nervous system, driven by complex genomic and epigenomic dysregulation. Its pathogenesis involves aberrant DNA methylation patterns at CpG islands of numbers of genes like OLIG1 and OLIG2 disrupting protein expression at myelin with compromised oligodendrocyte differentiation. Furthermore, histone modifications, particularly H3K4me3 and H3K27ac, alter the promoter regions of genes responsible for myelination, affecting myelin synthesis. MS exhibits chromosomal instability and copy number variations in immune-regulatory gene loci, contributing to the elevated expression of genes for pro-inflammatory cytokines (TNF-α, IL-6) and reductions in anti-inflammatory molecules (IL-10, TGF-β1). Vitamin D deficiency correlates with compromised immune regulation through hypermethylation and reduced chromatin accessibility of vitamin D receptor (VDR) dysfunction and is reported to be associated with dopaminergic neuronal loss. Vitamin D supplementation demonstrates therapeutic potential through binding with VDR, which facilitates nuclear translocation and subsequent transcriptional activation of target genes via vitamin D response elements (VDREs), resulting in suppression of NF-κB signalling, enhancement of regulatory T-cell (T_reg) responses due to upregulation of specific genes like FOXP3, downregulation of pro-inflammatory pathways, and potential restoration of the chromatin accessibility of oligodendrocyte-specific gene promoters, which normalizes oligodendrocyte activity. Identification of differentially methylated regions (DMRs) and differentially expressed genes (DEGs) that are in proximity to VDR-mediated gene regulation supports vitamin D supplementation as a promising, economically viable, and sustainable therapeutic strategy for MS. This systematic review integrates clinical evidence and eventual bioinformatical meta-analyses that reference transcriptome and methylome profiling and identify prospective molecular targets that represent potential genetic and epigenetic biomarkers for personalized therapeutic intervention. Full article

The ability of common carp to withstand both short-term and long-term oxygen deprivation has been well documented; however, the potential genetic mechanisms behind common carp’s hypoxia response remain unclear. Therefore, to understand the possible genetic foundation of their response to hypoxia, comparative genomic analyses were conducted among six common carp varieties: Color, Songpu, European, Yellow, Mirror, and Hebao common carps. We identified 118 single-copy orthologous positively selected genes (PSGs) (dN/dS > 1) in all common carps under study, with GO functions directly related to the cellular responses to hypoxia in Color and European common carp PSGs, such as oxygen transport activity, oxygen binding activity, respiratory burst activity, and superoxide anion production. The Bayes Empirical Bayes (BEB) technique identified possible amino acid substitutions in mitochondrial and hypoxic genes under positive selection. Exonic and intronic structural variations (SVs) were discovered in the CYGB2 hypoxia-related gene of Color and European common carps, as well as in several mitochondrial genes, including MRPL20, MRPL32, NSUN3, GUF1, TMEM17B, PDE12, ACAD6, and COX10 of Color, European, Songpu, Yellow, and Hebao common carps. Moreover, Color common carp and Songpu common carp were found to share the greatest percentage of collinear genes (49.8%), with seven Songpu common carp chromosomes (chr A2, chr A9, chr A13, chr B13, chr B15, chr B2, and chr B12) showing distinct translocation events with the corresponding chromosomes of Color common carp. Additionally, we found 570 translocation sites that contained 3572 translocation-related genes in Color common carp, some of which are directly relevant to mitochondrial and hypoxic GO functions and KEGG pathways. Our results offer strong genome-wide evidence of the possible evolutionary response of Cyprinus carpio to hypoxia, providing important insights into the potential molecular mechanisms that explain their survival in hypoxic environments and guiding future research into carp hypoxia tolerance. Full article

Acute promyelocytic leukemia (APL) is a rare subtype of acute myeloid leukemia (AML) characterized by chromosomal translocation forming the fusion protein that blocks the differentiation of myeloid progenitors and increases the self-renewal of leukemia cells. The introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has dramatically improved outcomes in APL, making it a leading example of successful treatment through differentiation of cancer cells. However, life-threatening side effects and treatment resistance may develop; therefore, modulation of the safety and efficacy of these drugs may contribute to further improving treatment results. Recently, zinc, involved in the structure and function of transcription factors, has received special attention for its potential role in the development and treatment response of cancer. Zinc homeostasis is disrupted in APL, with intracellular accumulation stabilizing oncogenic proteins. Zinc depletion promotes degradation of PML–RARA and induces apoptosis, while supplementation enhances genotoxic stress in leukemic cells but protects normal hematopoiesis. Zinc also regulates key transcription factors involved in differentiation and proliferation, including RUNX2, KLF4, GFI1, and CREB. In this review, we examine how zinc may impact zinc-finger (ZnF) and non-ZnF transcription factors and differentiation therapy in APL, thereby identifying potential strategies to enhance treatment efficacy and minimize side effects. Full article

Background/Objectives: Synovial sarcoma (SS) is an aggressive soft-tissue tumor characterized by the chromosomal translocation t(X;18) (p11.2;q11.2), most commonly involving the fusion of the SYT gene on chromosome 18 with the SSX1 or SSX2 genes on chromosome X. This study aims to explore the clinicopathological and molecular characteristics of synovial sarcoma in a cohort of Moroccan patients. Methods: We analyzed 48 cases of synovial sarcoma using formalin-fixed, paraffin-embedded (FFPE) tissue samples. Histological grading was performed according to the FNCLCC system. Immunohistochemical staining was employed to detect cytokeratin (CK) and epithelial membrane antigen (EMA). Molecular analysis included fluorescence in situ hybridization (FISH) to identify SS18 gene rearrangements and reverse transcription–polymerase chain reaction (RT-PCR) to detect SYT-SSX fusion transcripts. Results: Among the cohort, 56% of cases showed SS18 gene rearrangements via FISH, while RT-PCR confirmed the presence of SS18-SSX1 and SS18-SSX2 transcripts in 60% and 32% of cases, respectively. The remainder was classified as undifferentiated sarcoma. Notably, no significant associations were observed between SYT-SSX fusion type and clinicopathological features. Conclusions: These findings underscore the importance of integrating molecular techniques for precise diagnosis in synovial sarcoma. The results align with global patterns, emphasizing the necessity for molecular testing to enhance diagnostic accuracy and informing potential therapeutic advancements. Full article

Duchenne muscular dystrophy (DMD) is typically described in boys with a pathogenic variant in the DMD. However, in certain cases, females may also exhibit symptoms of this X-linked disorder. In the present study, the cause of Duchenne muscular dystrophy in three girls was reciprocal translocations t(X;2), t(X;12), and t(X;16), with breakpoints located within the DMD gene sequence. All patients had global development delay, predominantly proximal muscle weakness, calf muscle hypertrophy, and elevated creatine kinase levels up to 100 times the normal range (16,000–26,694 U/L). All underwent cardiac ultrasound and electromyography, and two of the girls also had muscle MRI data. After receiving negative results of MLPA aimed at the detection of DMD deletions and duplications, as well as the limb-girdle muscular dystrophy gene panel sequencing, the patients were referred to whole genome sequencing, which allowed to detect a translocation involving the short arm of the X chromosome and with breakpoints in the DMD. Karyotyping confirmed reciprocal translocations in all patients, with de novo status established in all three cases. The results of this study contribute to the understanding of clinical polymorphism and genetic heterogeneity of the disease, highlighting the importance of a comprehensive approach to genetic diagnostics in atypical cases. Full article

Insights into the state of individual cells within a living organism are essential for identifying diseases and abnormalities. The internal state of a cell is reflected in its morphological features and changes in the localization of intracellular molecules. Using this information, it is possible to infer the state of the cells with high precision. In recent years, technological advancements and improvements in instrument specifications have made large-scale analyses, such as single-cell analysis, more widely accessible. Among these technologies, imaging flow cytometry (IFC) is a high-throughput imaging platform that can simultaneously acquire information from flow cytometry (FCM) and cellular images. While conventional FCM can only obtain fluorescence intensity information corresponding to each detector, IFC can acquire multidimensional information, including cellular morphology and the spatial arrangement of proteins, nucleic acids, and organelles for each imaging channel. This enables the discrimination of cell types and states based on the localization of proteins and organelles, which is difficult to assess accurately using conventional FCM. Because IFC can acquire a large number of single-cell morphological images in a short time, it is well suited for automated classification using machine learning. Furthermore, commercial instruments that combine integrated imaging and cell sorting capabilities have recently become available, enabling the sorting of cells based on their image information. In this review, we specifically highlight practical applications of IFC in four representative areas: cell cycle analysis, protein localization analysis, immunological synapse formation, and the detection of leukemic cells. In addition, particular emphasis is placed on applications that directly contribute to elucidating molecular mechanisms, thereby distinguishing this review from previous general overviews of IFC. IFC enables the estimation of cell cycle phases from large numbers of acquired cellular images using machine learning, thereby allowing more precise cell cycle analysis. Moreover, IFC has been applied to investigate intracellular survival and differentiation signals triggered by external stimuli, to monitor DNA damage responses such as γH2AX foci formation, and more recently, to detect immune synapse formation among interacting cells within large populations and to analyze these interactions at the molecular level. In hematological malignancies, IFC combined with fluorescence in situ hybridization (FISH) enables high-throughput detection of chromosomal abnormalities, such as BCR-ABL1 translocations. These advances demonstrate that IFC provides not only morphological and functional insights but also clinically relevant genomic information at the single-cell level. By summarizing these unique applications, this review aims to complement existing publications and provide researchers with practical insights into how IFC can be implemented in both basic and translational research. Full article