Updates in KMT2A Gene Rearrangement in Pediatric Acute Lymphoblastic Leukemia

KMT2A-CBL fusion gene in the first reported case of T-cell acute lymphoblastic leukemia associated with Wiedemann-Steiner syndrome

Wiedemann-Steiner syndrome (WSS) is a congenital malformation syndrome characterized by intellectual disability, developmental delay, and distinctive facial features, caused by germline mutations in the KMT2A gene. Despite the key role of KMT2A in hematopoiesis, leukemia has not been previously reported in WSS patients. This report presents the first documented case of acute lymphoblastic leukemia (ALL) in a WSS patient. A 16-year-old boy with developmental delay, distinct facial features, and genital abnormalities was diagnosed with WSS following the identification of a heterozygous frameshift mutation in KMT2A. At age 17, he developed T-cell ALL harboring the KMT2A-CBL fusion gene, of which only nine cases have been reported so far. cDNA sequence analysis of the KMT2A-CBL transcript at the site of the germline KMT2A pathogenic variant revealed a wild-type sequence, indicating that the KMT2A-CBL fusion occurred on the wild-type allele. While this observation suggests a potential cooperative role of the KMT2A-CBL chimeric gene and the germline KMT2A pathogenic mutation in leukemogenesis, the rarity of leukemia in WSS underscores the need for cautious interpretation. This case provides preliminary insights into a possible mechanism of leukemogenesis in WSS, but further studies are required to clarify the relationship between WSS and ALL.

Hemophagocytic Lymphohistiocytosis with Predominant T-Lymphocytes in Young Child: An Unusual Presentation of Evolving Acute Myeloid Leukemia

Background: Hemophagocytic lymphohistiocytosis (HLH) is an aggressive, life-threatening condition commonly observed in young children. Distinguishing primary HLH from secondary HLH, such as malignancy-associated HLH, can be challenging, potentially leading to misdiagnosis and inappropriate treatment. Case presentation: A 16-month-old female presented with fever, decreased appetite, and rhinorrhea. A review of the peripheral blood smear revealed anemia and leukopenia, with absolute neutropenia characterized by a high lymphocyte count (approximately 80% were T cells by flow cytometry). Flow cytometry was negative for immunophenotypically abnormal cells. Initially, the cytopenia was attributed to a viral infection. However, the cytopenia did not improve, and a bone marrow evaluation revealed evidence of HLH but no immunophenotypically abnormal population. An extensive work-up for HLH, including next-generation sequencing (NGS) and cytogenetic testing identified the KMT2A::MLLT3 fusion transcript, indicating malignancy-associated HLH in the setting of evolving leukemia. Because there was no increase in blasts or immunophenotypically abnormal cells, the diagnosis of leukemia could not be made at that time. The patient was closely monitored and, seven weeks later, was diagnosed with acute myeloid leukemia/acute monocytic leukemia. In addition to the KMT2A::MLLT3 fusion, pathogenic variants in the PTPN11 and FLT3 genes were detected by NGS. Conclusions: The presentation of evolving acute monocytic leukemia can be nonspecific, mimicking conditions such as HLH, without an initial increase in immature cells or monocytes. Maintaining a broad differential diagnosis and including comprehensive molecular genetic testing may facilitate early diagnosis and appropriate treatment.

Application of Omics Analyses in Pediatric B-Cell Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, comprising almost 25% of all malignancies diagnosed in children younger than 20 years, and its incidence is still increasing. ALL is a blood cancer arising from the unregulated proliferation of clonal lymphoid progenitor cells. To make a diagnosis of B-cell ALL, bone marrow morphology and immunophenotyping are needed; cerebrospinal fluid examination, and chromosomal analysis are currently used as stratification exams. Currently, almost 70% of children affected by B-cell ALL are characterized by well-known cytogenetic abnormalities. However, the integration of results with "omic" techniques (genomics, transcriptomics, proteomics, and metabolomics, both individually and integrated) able to analyze simultaneously thousands of molecules, has enabled a deeper definition of the molecular scenario of B-cell ALL and the identification of new genetic alterations. Studies based on omics have greatly deepened our knowledge of ALL, expanding the horizon from the traditional morphologic and cytogenetic point of view. In this review, we focus our attention on the "omic" approaches mainly used to improve the understanding and management of B-cell ALL, crucial for the diagnosis, prognosis, and treatment of the disease, offering a pathway toward more precise and personalized therapeutic interventions.

Comprehensive genomic characterization of hematologic malignancies at a pediatric tertiary care center

Despite the increasing availability of comprehensive next generation sequencing (NGS), its role in characterizing pediatric hematologic malignancies remains undefined. We describe findings from comprehensive genomic profiling of hematologic malignancies at a pediatric tertiary care center. Patients enrolled on a translational research protocol to aid in cancer diagnosis, prognostication, treatment, and detection of cancer predisposition. Disease-involved samples underwent exome and RNA sequencing and analysis for single nucleotide variation, insertion/deletions, copy number alteration, structural variation, fusions, and gene expression. Twenty-eight patients with hematologic malignancies were nominated between 2018-2021. Eighteen individuals received both germline and somatic sequencing; two received germline sequencing only. Germline testing identified patients with cancer predisposition syndromes and non-cancer carrier states. Fifteen patients (15/18, 83%) had cancer-relevant somatic findings. Potential therapeutic targets were identified in seven patients (7/18, 38.9%); three (3/7, 42.9%) received targeted therapies and remain in remission an average of 47 months later.

Menin inhibitors for the treatment of acute myeloid leukemia: challenges and opportunities ahead

The AML treatment landscape has significantly changed in recent years with the approval of targeted therapies in the front-line and relapsed/refractory settings, including inhibitors of FLT3 and IDH1/2 mutations. More importantly, approval of the combination of the BCl-2 inhibitor, venetoclax, and hypomethylating agents or low dose cytarabine provided unprecedented breakthrough for the frontline treatment of older, unfit AML patients. Even with all this exciting progress, more targeted therapies for AML treatment are needed. Recent development of menin inhibitors targeting AML with KMT2A rearrangements or NPM1 mutations could represent a promising new horizon of treatment for patients within these subsets of AML. Our current review will focus on a summary and updates of recent developments of menin inhibitors in the treatment of AML, on the challenges ahead arising from drug resistance, as well as on the opportunities of novel combinations with menin inhibitors.

Elucidating the role of MLL1 nsSNPs: Structural and functional alterations and their contribution to leukemia development

(1) BACKGROUND

The Mixed lineage leukemia 1 (MLL1) gene, located on chromosome 11q23, plays a pivotal role in histone lysine-specific methylation and is consistently associated with various types of leukemia. Non-synonymous Single Nucleotide Polymorphisms (nsSNPs) have been tied to numerous diseases, including cancers, and have become valuable cancer biomarkers. There's a notable gap in studies probing the influence of SNPs on MLL1 protein structure, function, and subsequent modifications.

(2) METHODS

We utilized an array of bioinformatics tools, including PredictSNP, InterPro, ConSurf, I-Mutant2.0, MUpro, Musitedeep, Project HOPE, RegulomeDB, Mutpred2, and both CScape and CScape Somatic, to meticulously analyze the consequences of nsSNPs in the MLL1 gene.

(3) RESULTS

Out of 2,097 nsSNPs analyzed, 62 were determined to be significantly pathogenic by the PredictSNP tool, with ten crucial MLL1 functional domains identified using InterPro. Additionally, 50 of these nsSNPs had high conservation scores, hinting at potential effects on protein structure and function, while 32 were found to undermine MLL1 protein stability. Notably, four nsSNPs were deemed oncogenic, with two identified as cancer drivers. The nsSNP, D2724G, between the MLL1 protein's FY-rich domains, could disrupt proteolytic cleavage, altering gene expression patterns and potentially promoting cancer.

(4) CONCLUSIONS

Our research provides a comprehensive assessment of nsSNPs' impact in the MLL1 protein structure and function and consequently on leukemia development, suggesting potential avenues for personalized treatment, early detection, improved prognosis, and a deeper understanding of hematological malignancy genesis.

Histone methyltransferase KMT2A: Developmental regulation to oncogenic transformation

Our current understanding of epigenetic regulation is deeply rooted in the founding contributions of Dr C. David Allis. In 2002, Allis and colleagues first characterized the lysine methyltransferase activity of the mammalian KMT2A (MLL1), a paradigm-shifting discovery that brings epigenetic dysregulation into focus for many human diseases that carry KMT2A mutations. This review will discuss the current understanding of the multifaceted roles of KMT2A in development and disease, which has paved the way for innovative and upcoming approaches to cancer therapy.

Preclinical efficacy of the potent, selective menin-KMT2A inhibitor JNJ-75276617 (bleximenib) in KMT2A- and NPM1-altered leukemias

ABSTRACT

The interaction between menin and histone-lysine N-methyltransferase 2A (KMT2A) is a critical dependency for KMT2A- or nucleophosmin 1 (NPM1)-altered leukemias and an emerging opportunity for therapeutic development. JNJ-75276617 (bleximenib) is a novel, orally bioavailable, potent, and selective protein-protein interaction inhibitor of the binding between menin and KMT2A. In KMT2A-rearranged (KMT2A-r) and NPM1-mutant (NPM1c) acute myeloid leukemia (AML) cells, JNJ-75276617 inhibited the association of the menin-KMT2A complex with chromatin at target gene promoters, resulting in reduced expression of several menin-KMT2A target genes, including MEIS1 and FLT3. JNJ-75276617 displayed potent antiproliferative activity across several AML and acute lymphoblastic leukemia (ALL) cell lines and patient samples harboring KMT2A or NPM1 alterations in vitro. In xenograft models of AML and ALL, JNJ-75276617 reduced leukemic burden and provided a significant dose-dependent survival benefit accompanied by expression changes of menin-KMT2A target genes. JNJ-75276617 demonstrated synergistic effects with gilteritinib in vitro in AML cells harboring KMT2A-r. JNJ-75276617 further exhibited synergistic effects with venetoclax and azacitidine in AML cells bearing KMT2A-r in vitro, and significantly increased survival in mice. Interestingly, JNJ-75276617 showed potent antiproliferative activity in cell lines engineered with recently discovered mutations (MEN1M327I or MEN1T349M) that developed in patients refractory to the menin-KMT2A inhibitor revumenib. A cocrystal structure of menin in complex with JNJ-75276617 indicates a unique binding mode distinct from other menin-KMT2A inhibitors, including revumenib. JNJ-75276617 is being clinically investigated for acute leukemias harboring KMT2A or NPM1 alterations, as a monotherapy for relapsed/refractory acute leukemia (NCT04811560), or in combination with AML-directed therapies (NCT05453903).

The Ubiquitin-Conjugating Enzyme E2 O (UBE2O) and Its Therapeutic Potential in Human Leukemias and Solid Tumors

Protein degradation is a biological phenomenon essential for cellular homeostasis and survival. Selective protein degradation is performed by the ubiquitination system which selectively targets proteins that need to be eliminated and leads them to proteasome degradation. In this narrative review, we focus on the ubiquitin-conjugating enzyme E2 O (UBE2O) and highlight the role of UBE2O in many biological and physiological processes. We further discuss UBE2O's implications in various human diseases, particularly in leukemias and solid cancers. Ultimately, our review aims to highlight the potential role of UBE2O as a therapeutic target and offers new perspectives for developing targeted treatments for human cancers.

Immune escape of B-cell lymphoblastic leukemic cells through a lineage switch to acute myeloid leukemia

Acute leukemia (AL) with a lineage switch (LS) is associated with poor prognosis. The predisposing factors of LS are unknown, apart from KMT2A rearrangements that have been reported to be associated with LS. Herein, we present two cases and review all 104 published cases to identify risk factors for LS. Most of the patients (75.5%) experienced a switch from the lymphoid phenotype to the myeloid phenotype. Eighteen patients (17.0%) experienced a transformation from acute myelogenous leukemia (AML) to acute lymphoblastic leukemia (ALL). Forty-nine (46.2%) patients carried a KMT2A rearrangement. Most of the cases involved LS from B-cell ALL (B-ALL) to AML (59.4%), and 49 patients (46.2%) carried KMT2A-rearrangements. Forty patients (37.7%) received lineage-specific immunotherapy. Our findings suggest that the prevalence of KMT2A rearrangements together with the lineage-specific immunotherapy may trigger LS, which supports the thesis of the existence of leukemia stem cells that are capable of lymphoid or myeloid differentiation.

Uncovering a Genetic Diagnosis in a Pediatric Patient by Whole Exome Sequencing: A Modeling Investigation in Wiedemann-Steiner Syndrome

Background: Wiedemann-Steiner syndrome (WSS), a rare autosomal-dominant disorder caused by haploinsufficiency of the KMT2A gene product, is part of a group of disorders called chromatinopathies. Chromatinopathies are neurodevelopmental disorders caused by mutations affecting the proteins responsible for chromatin remodeling and transcriptional regulation. The resulting gene expression dysregulation mediates the onset of a series of clinical features such as developmental delay, intellectual disability, facial dysmorphism, and behavioral disorders. Aim of the Study: The aim of this study was to investigate a 10-year-old girl who presented with clinical features suggestive of WSS. Methods: Clinical and genetic investigations were performed. Whole exome sequencing (WES) was used for genetic testing, performed using Illumina technology. The bidirectional capillary Sanger resequencing technique was used in accordance with standard methodology to validate a mutation discovered by WES in all family members who were available. Utilizing computational protein modeling for structural and functional studies as well as in silico pathogenicity prediction models, the effect of the mutation was examined. Results: WES identified a de novo heterozygous missense variant in the KMT2A gene KMT2A(NM_001197104.2): c.3451C>G, p.(Arg1151Gly), absent in the gnomAD database. The variant was classified as Likely Pathogenetic (LP) according to the ACMG criteria and was predicted to affect the CXXC-type zinc finger domain functionality of the protein. Modeling of the resulting protein structure suggested that this variant changes the protein flexibility due to a variation in the Gibbs free energy and in the vibrational entropy energy difference between the wild-type and mutated domain, resulting in an alteration of the DNA binding affinity. Conclusions: A novel and de novo mutation discovered by the NGS approach, enhancing the mutation spectrum in the KMT2A gene, was characterized and associated with WSS. This novel KMT2A gene variant is suggested to modify the CXXC-type zinc finger domain functionality by affecting protein flexibility and DNA binding.

Hyperleukocytosis in Pediatric Patients with Acute Lymphoblastic Leukemia: Demographic and Clinical Characteristics

Background: Hyperleukocytosis, defined as a total leukocyte count of more than 50,000/mm3 leukocytes, occurs in almost one in five children with acute lymphoblastic leukemia (ALL). It represents an unfavorable prognostic factor in this disease. The aim of the following study was to describe demographic and clinical features in patients with hyperleukocytosis and their relationship with leukocyte count. Methods: We retrospectively analyzed the available medical data of patients with ALL diagnosed and treated at the University Children's Hospital in Lublin between 2017 and 2024. Results: Of the 97 patients, 10 (10.3%) had hyperleukocytosis. They were significantly more likely to be older boys diagnosed with T-ALL. The group with hyperleukocytosis had a higher mortality rate. The presence of hyperleukocytosis also correlated with the presence of petechiae, thrombocyte and neutrophil counts, and LDH activity. Patients with hyperleukocytosis also experienced a higher incidence of infections as a complication of therapy as leukocyte counts increased. Conclusions: Hyperleukocytosis, although rare, is an important factor in the course of ALL, both clinically and prognostically.

Prediction of Response to FDA-Approved Targeted Therapy and Immunotherapy in Acute Lymphoblastic Leukemia (ALL)

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) represents the predominant cancer in pediatric populations, though its occurrence in adults is relatively rare. Pre-treatment risk stratification is crucial for predicting prognosis. Important factors for assessment include patient age, white blood cell (WBC) count at diagnosis, extramedullary involvement, immunophenotype, and cytogenetic aberrations. Minimal residual disease (MRD), primarily assessed by flow cytometry following remission, plays a substantial role in guiding management plans. Over the past decade, significant advancements in ALL outcomes have been witnessed. Conventional chemotherapy has remarkably reduced mortality rates; however, its intensive nature raises safety concerns and has led to the emergence of treatment-resistant cases with recurrence of relapses. Consequently, The U.S. Food and Drug Administration (FDA) has approved several novel treatments for relapsed/refractory ALL due to their demonstrated efficacy, as indicated by improved complete remission and survival rates. These treatments include tyrosine kinase inhibitors (TKIs), the anti-CD19 monoclonal antibody blinatumomab, anti-CD22 inotuzumab ozogamicin, anti-CD20 rituximab, and chimeric antigen receptor (CAR) T-cell therapy. Identifying the variables that influence treatment decisions is a pressing necessity for tailoring therapy based on heterogeneous patient characteristics. Key predictive factors identified in various observational studies and clinical trials include prelymphodepletion disease burden, complex genetic abnormalities, and MRD. Furthermore, the development of serious adverse events following treatment could be anticipated through predictive models, allowing for appropriate prophylactic measures to be considered. The ultimate aim is to incorporate the concept of precision medicine in the field of ALL through valid prediction platform to facilitate the selection of the most suitable treatment approach.

KMT2A Rearrangements in Leukemias: Molecular Aspects and Therapeutic Perspectives

KMT2A (alias: mixed-lineage leukemia [MLL]) gene mapping on chromosome 11q23 encodes the lysine-specific histone N-methyltransferase 2A and promotes transcription by inducing an open chromatin conformation. Numerous genomic breakpoints within the KMT2A gene have been reported in young children and adults with hematologic disorders and are present in up to 10% of acute leukemias. These rearrangements describe distinct features and worse prognosis depending on the fusion partner, characterized by chemotherapy resistance and high rates of relapse, with a progression-free survival of 30-40% and overall survival below 25%. Less intensive regimens are used in pediatric patients, while new combination therapies and targeted immunotherapeutic agents are being explored in adults. Beneficial therapeutic effects, and even cure, can be reached with hematopoietic stem cell transplantation, mainly in young children with dismal molecular lesions; however, delayed related toxicities represent a concern. Herein, we summarize the translocation partner genes and partial tandem duplications of the KMT2A gene, their molecular impact, clinical aspects, and novel targeted therapies.

Genomic Characterization of Partial Tandem Duplication Involving the KMT2A Gene in Adult Acute Myeloid Leukemia

BACKGROUND

Gene rearrangements affecting KMT2A are frequent in acute myeloid leukemia (AML) and are often associated with a poor prognosis. KMT2A gene fusions are often detected by chromosome banding analysis and confirmed by fluorescence in situ hybridization. However, small intragenic insertions, termed KMT2A partial tandem duplication (KMT2A-PTD), are particularly challenging to detect using standard molecular and cytogenetic approaches.

METHODS

We have validated the use of a custom hybrid-capture-based next-generation sequencing (NGS) panel for comprehensive profiling of AML patients seen at our institution. This NGS panel targets the entire consensus coding DNA sequence of KMT2A. To deduce the presence of a KMT2A-PTD, we used the relative ratio of KMT2A exons coverage. We sought to corroborate the KMT2A-PTD NGS results using (1) multiplex-ligation probe amplification (MLPA) and (2) optical genome mapping (OGM).

RESULTS

We analyzed 932 AML cases and identified 41 individuals harboring a KMT2A-PTD. MLPA, NGS, and OGM confirmed the presence of a KMT2A-PTD in 22 of the cases analyzed where orthogonal testing was possible. The two false-positive KMT2A-PTD calls by NGS could be explained by the presence of cryptic structural variants impacting KMT2A and interfering with KMT2A-PTD analysis. OGM revealed the nature of these previously undetected gene rearrangements in KMT2A, while MLPA yielded inconclusive results. MLPA analysis for KMT2A-PTD is limited to exon 4, whereas NGS and OGM resolved KMT2A-PTD sizes and copy number levels.

CONCLUSIONS

KMT2A-PTDs are complex gene rearrangements that cannot be fully ascertained using a single genomic platform. MLPA, NGS panels, and OGM are complementary technologies applied in standard-of-care testing for AML patients. MLPA and NGS panels are designed for targeted copy number analysis; however, our results showed that integration of concurrent genomic alterations is needed for accurate KMT2A-PTD identification. Unbalanced chromosomal rearrangements overlapping with KMT2A can interfere with the diagnostic sensitivity and specificity of copy-number-based KMT2A-PTD detection methodologies.

Impact of Histone Lysine Methyltransferase SUV4-20H2 on Cancer Onset and Progression with Therapeutic Potential

Histone lysine methyltransferase SUV4-20H2, a member of the suppressor of variegation 4-20 homolog (SUV4-20) family, has a critical impact on the regulation of chromatin structure and gene expression. This methyltransferase establishes the trimethylation of histone H4 lysine 20 (H4K20me3), a repressive histone mark that affects several cellular processes. Deregulated SUV4-20H2 activity has been associated with altered chromatin dynamics, leading to the misregulation of key genes involved in cell cycle control, apoptosis and DNA repair. Emerging research evidence indicates that SUV4-20H2 acts as a potential epigenetic modifier, contributing to the development and progression of several malignancies, including breast, colon and lung cancer, as well as renal, hepatocellular and pancreatic cancer. Understanding the molecular mechanisms that underlie SUV4-20H2-mediated effects on chromatin structure and gene expression may provide valuable insights into novel therapeutic strategies for targeting epigenetic alterations in cancer. Herein, we discuss structural and functional aspects of SUV4-20H2 in cancer onset, progression and prognosis, along with current targeting options.

A single scalp nodule as the first presentation of acute lymphoblastic leukemia (KMT2A::MLLT3) in a healthy-appearing infant: a case report

Background

Infant leukemia is a rare form of acute leukemia diagnosed prior to the age of 1 and is characterized by an extremely poor prognosis due to its dismal response to current therapeutic approaches. It comprises about 4% of all childhood cases of acute lymphoblastic leukemia (ALL). Isolated initial cutaneous involvement in ALL is uncommon, and even more so in infant ALL.

Case presentation

Here, we present the case of a 2-month-old healthy-appearing infant, initially presenting with a single scalp nodule and subsequently diagnosed with an infant ALL. The leukemia was characterized by the most immature B-lineage immunophenotype [pro-B ALL/B-I, according to the European Group for the Immunological Characterization of Leukaemias (EGIL) classification] and chromosomal translocation t(9;11)(p22;q23), resulting in fusion gene KMTLA2::MLLT3, which is considered a negative prognostic factor. The patient underwent hematopoietic stem cell transplantation and is still in remission.

Conclusions

This case is peculiar because of the rare occurrence of isolated initial cutaneous involvement in ALL. Despite the healthy appearance of the patient, every suspicious symptom suggestive of malignancies should be further investigated to anticipate the diagnosis and start treatment early.

Leukemia Cutis-The Current View on Pathogenesis, Diagnosis, and Treatment

Leukemia cutis (LC) is defined as the leukemic infiltration of the epidermis, the dermis, and the subcutaneous tissue. Leukemia cutis may follow or occur simultaneously with the diagnosis of systemic leukemia. However, cutaneous lesions are occasionally diagnosed as the primary manifestation of leukemia. Leukemic skin infiltrations demonstrate considerable variation regarding a number of changes, distribution, and morphology. The highest incidence of LC is observed in chronic lymphocytic leukemia, monocytic and myelomonocytic acute myeloid leukemia, and T-cell lineage leukemia. Although the pathogenic mechanism of the invasion of leukemic cells into the skin is not well understood, chemokine receptors and adhesion molecules as well as the genetic characteristics of leukemia are thought to play a role. Leukemic skin lesions may be localized or disseminated and may occur alone or in combination on any site of the skin, most frequently in the trunk and extremities. The most common clinical presentations of leukemia cutis are papules, nodules, macules, plaques, and ulcers. In most patients, the complete or partial resolution of cutaneous infiltrations occurs simultaneously with hematologic remission. However, in patients with resistant disease or recurrent skin infiltration, local radiotherapy can be used. This review presents recent data on the pathogenesis, diagnosis, and treatment of leukemic skin involvement in different types of leukemia.

Cryptic KMT2A/MLLT10 fusion detected by next-generation sequencing in a case of pediatric acute megakaryoblastic leukemia

KMT2A (11q23.3) gene rearrangements are found in acute leukemia and are associated with a poor or intermediate prognosis. MLLT10 is the fourth most common gene fusion partner for KMT2A. A reciprocal translocation t(10;11) is insufficient to produce an in-frame KMT2A/MLLT10 fusion, because the genes involved in the rearrangement have opposite transcriptional orientations. In order to bring KMT2A and MLLT10 into juxtaposition, complex rearrangements are required. Until now, conventional chromosome, fluorescence in situ hybridization (FISH), and reverse transcriptase-polymerase chain reaction (RT-PCR) studies have been used to detect KMT2A/MLLT10 fusions. However, conventional studies have limitations, such as poor and inconsistent resolution, when compared to next-generation sequencing (NGS). In this study, we report a pediatric patient with acute megakaryoblastic leukemia, in whom the cryptic KMT2A/MLLT10 fusion was not detected by KMT2A break-apart probe FISH and chromosome analysis, but detected by NGS. In this patient, NGS showed cryptic insertion of MLLT10 exons 9-24 into intron 9 of KMT2A, resulting in a KMT2A/MLLT10 fusion. Therefore, NGS is a valuable complementary option for the evaluation of structural aberrations, especially those with a cryptic size.

BRD4 Protein as a Target for Lung Cancer and Hematological Cancer Therapy: A Review

The BET protein family plays a crucial role in regulating the epigenetic landscape of the genome. Their role in regulating tumor-related gene expression and its impact on the survival of tumor cells is widely acknowledged. Among the BET family constituents, BRD4 is a significant protein. It is a bromodomain-containing protein located at the outer terminal that recognizes histones that have undergone acetylation. It is present in the promoter or enhancer region of the target gene and is responsible for initiating and sustaining the expression of genes associated with tumorigenesis. BRD4 expression is significantly elevated in various tumor types. Research has indicated that BRD4 plays a significant role in regulating various transcription factors and chromatin modification, as well as in repairing DNA damage and preserving telomere function, ultimately contributing to the survival of cancerous cells. The protein BRD4 has a significant impact on antitumor therapy, particularly in the management of lung cancer and hematological malignancies, and the promising potential of BRD4 inhibitors in the realm of cancer prevention and treatment is a topic of great interest. Therefore, BRD4 is considered a promising candidate for prophylaxis and therapy of neoplastic diseases. However, further research is required to fully comprehend the significance and indispensability of BRD4 in cancer and its potential as a therapeutic target.