Humans ; Leukemia, Myeloid, Acute/genetics* ; Myeloid-Lymphoid Leukemia Protein/genetics* ; Oncogene Proteins, Fusion/genetics* ; Translocation, Genetic

Humans ; Child ; Myeloid-Lymphoid Leukemia Protein/genetics* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Ubiquitin Thiolesterase

OBJECTIVETo study the clinical and laboratory features of childhood acute leukemia (AL) with MLL gene rearrangements.

METHODSSixteen of 298 cases of childhood AL with MLL rearrangements were studied by using MLL dual-color FISH, multiplex RT-PCR with 13 pairs of primers in combination with R banding karyotype analysis and cell immunophenotyping by flow cytometry.

RESULTSSixteen cases of childhood AL with MLL rearrangements accounted for 5.4% of 298 AL patients, and 56.3% of infant ALs. Among 106 cases analyzed by multiplex RT-PCR, MLL gene rearrangements were found in 11 cases, including MLL/AF4 fusion gene in 2, MLL/AF6 fusion gene in 1, MLL/AF6 and MLL/ELL combined with MLL/ AFX or HOX11 in one case each, MLL/AF9 in 2, MLL/AF10 in 1, MLL/ELL in 2. MLL partial tandem duplication in 1 and activated HOX11 in 1. In 27 cases assayed by FISH, 9 cases (36.0%) were demonstrated MLL gene rearrangements. In 16 patients with MLL gene rearrangements, 14 (87.5%) exhibited clonal chromosome abnormalities involved chromosome 11 in 11 cases: being t(4;11) in 2, t(6;11), t(8;11), t(7;8;11), t(9;11) in each trisomy 11 in 2 and 11q--in 3 cases. Among these 16 patients, 11 were B-ALL, and 5 AML-M5, 3 of the latter were CD7+ and CD2+. Of these 16 patients, 8 received chemotherapy and 7 of them achieved complete remission, while the other 8 patients gave up treatment.

CONCLUSIONMultiplex RT-PCR combined with FISH provided a more accurate and sensitive method for detection of MLL gene rearrangements. Finding out MLL gene rearrangement is of most importance in guiding therapy and predicting prognosis in childhood AL.

Adolescent ; Child ; Child, Preschool ; Female ; Gene Rearrangement ; Humans ; In Situ Hybridization, Fluorescence ; Infant ; Leukemia ; genetics ; Male ; Myeloid-Lymphoid Leukemia Protein ; genetics

OBJECTIVE: To explore the genetic basis for a child with unexplained global developmental delay (GDD), seizure, and facial deformity. METHODS: Whole exome sequencing (WES) was carried out for the patient. Candidate variants were verified by Sanger sequencing of the patient and his parents. RESULTS: WES revealed that the patient has carried a previously unreported de novo heterozygous nonsense c.4906C>T (p.Arg1636Ter) variant of the KMT2A gene, Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.4906C>T variant of KMT2A gene was predicted to be pathogenic (PVS1+ PS2+ PM2+PP3). CONCLUSION The heterozygous nonsense c.4906C>T (p.Arg1636Ter) variant of the KMT2A gene probably underlay the disease in the child. Above finding has enriched the spectrum of pathogenic variants of the KMT2A gene.
Abnormalities, Multiple/genetics* ; Child ; Histone-Lysine N-Methyltransferase/genetics* ; Humans ; Intellectual Disability/genetics* ; Male ; Myeloid-Lymphoid Leukemia Protein/genetics* ; Syndrome

UNLABELLEDThis study was aimed to explore the value of detecting the expression levels of MLL-AF9 (mixed lineage leukemia, MLL) fusion gene during the treatment of acute myeloid leukemia (AML) by real-time fluorescence quantitative PCR (RQ-PCR), and to evaluate its prognostic significance in monitoring minimal residual disease (MRD). The expression levels of 11 patients with MLL-AF9 fusion gene positive were detected precisely by RQ-PCR during the treatment in order to analyze the correlation of detection results with clinical manifestations. The results showed that the expression levels of MLL-AF9 fusion gene in patients at initial diagnosis were 1.3%-55.28%.

RESULTSobtained from 5 patients who received chemotherapy alone during the interval between first and second courses of chemotherapy indicated that 2 patients with <0.1% of MLL-AF9 fusion gene expression levels all achieved hematologic complete remission and survived, while the remaining 3 patients with ≥ 0.1% of MLL-AF9 fusion gene did not achieve hematologic complete remission and only 1 case survived. Moreover, results obtained from 6 transplant patients within a month before the transplantation suggested that 4 of them with < 0.1% of MLL-AF9 fusion gene expression levels survived without relapses, while the remaining 2 patients with ≥ 0.1% of MLL-AF9 fusion gene expression levels relapsed and died. Besides, MLL-AF9 fusion gene expression levels were ≥ 0.1% within one month before the morphological relapse of bone marrow in 2 recurrent patients. It is concluded that the detecting the expression level of MLL-AF9 fusion gene by RQ-PCR is an effective and accurate method to quantify and monitor the MRD level of MLL-AF9 gene positive AML patients and may be used for early detecting molecular relapse of AML.

Humans ; Leukemia, Myeloid, Acute ; diagnosis ; genetics ; Myeloid-Lymphoid Leukemia Protein ; genetics ; Neoplasm, Residual ; genetics ; Oncogene Proteins, Fusion ; genetics ; Prognosis ; Real-Time Polymerase Chain Reaction ; methods

This study was purposed to investigate the incidence of mixed lineage leukemia (MLL) gene rearrangement and partner gene types as well as the clinical features and prognosis of acute leukemia (AL) with this rearrangement through detection in adult AL using combination of 3 techniques, and to evaluate the clinical value of this combination detection. The MLL gene rearrangement in 183 cases of adult AL was detected by combination of conventional cytogenetics, split signal FISH and multiplex nested PCR. The results showed that the incidence of MLL rearrangements in adult patients with AL was low (8.2%), and MLL-AF4 fusion gene was most common and predominant in acute lymphoblastic leukemia (ALL), while the MLL-AF6 and MLL-AF9 were most frequent in acute myeloid leukemia (AML). Extramedullary involvements were found in 40% of MLL-rearranged AL patients, and 33.3% of patients with MLL-rearranged AL reached to complete remission within 30 days during induction chemotherapy. In addition, in this cohort of MLL-rearranged adult AL patients, the 3-month relapse rate and 6-month overall survival rate were 50.0% and 50.0% respectively. It is concluded that the rate of missed diagnosis of CC technique for patients with MLL-rearranged AL reached to 60% in this study, while the combination of CC, FISH and multiplex nested PCR has been confirmed to have important significance for evaluating prognosis and conducting clinical therapy of patients with MLL-rearranged AL.
Adolescent ; Adult ; Aged ; Female ; Gene Rearrangement ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Male ; Middle Aged ; Myeloid-Lymphoid Leukemia Protein ; genetics ; Oncogene Proteins, Fusion ; genetics ; Young Adult

OBJECTIVE: To investigate the clinical features and prognosis of acute myeloid leukemia (AML) patients with the mixed lineage leukemia (MLL) gene rearrangements AF6 (MLL-AF6) positive. METHODS: In the study, 11 patients who were newly diagnosed with MLL-AF6 positive AML were analyzed retrospectively, related literature was reviewed to clarify the clinical features and prognosis of MLL-AF6 positive patients. RESULTS: Among the 11 patients, there were 6 males and 5 females, with a median age of 36 years. Six patients were diagnosed with AML M5 and five with M4 according to FAB classification (French-American-British classification systems). Gingival swelling and pain occurred in 6 cases and fever occurred in 5 cases. At first diagnosis, the median white blood cells were 55.5×10⁹/L. Immunotype showed the expression of myeloid/monocyte and early stem cell series antigens. The expression level of MLL-AF6 fusion gene (real-time quantitative PCR) was 14.2%-214.5%, and 6/11 cases (54.5%) were associated with high EVI1 gene expression. Mutations of KRAS, TET2, ASXL1, TP53, DNMT3A, and FLT3-ITD were detected by next generation sequencing (NGS) in 4 patients. Chromosome G banding examination showed that 2 cases were t(6;11)(q27, q23) with complex karyotype abnormality, 4 cases with +8 abnormality and 2 cases with normal karyotype. Hematological complete remission (CR) was achieved in 8/11 patients (72.7%) after conventional induction chemotherapy, and primary drug resistance was observed in 3 patients. Two of the eight patients with CR were negative for minimal residual disease (MRD), with a median CR duration of 4.5 months. Two patients with positive MRD and three patients with refractory recurrence underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), but all died due to leukemia progression. At the end of follow-up on December 1, 2019, 2 patients were alive and 9 died, with median survival time of 9 months. CONCLUSION The AML patients with MLL-AF6 positive were mostly young, the majority of FAB types were M4 and M5, and most of the patients often had fever as the first symptom, with increased white blood cells, accompanied by organ infiltration, and high EVI1 gene expression. The hematological remission rate of routine chemotherapy is not low, but it is difficult to achieve molecular remission, most of which have early recurrence. Early allo-HSCT in a molecular negative state may prolong the CR duration.
Adult ; Female ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Male ; Myeloid-Lymphoid Leukemia Protein/genetics* ; Oncogene Proteins, Fusion/genetics* ; Prognosis ; Remission Induction ; Retrospective Studies

BACKGROUNDPartial tandem duplication of mixed lineage leukaemia (MLL-PTD) is detected both in patients with acute leukemia and in healthy people. However, MLL-PTD in relatives of patients with MLL-PTD has not been reported. The objective of this study was to investigate the expression of MLL-PTD in patients with acute leukemia and in their relatives.

METHODSThe bone marrow or peripheral blood was collected from patients with acute leukaemia and their relatives. Nested reverse transcription-polymerase chain reaction (RT-PCR) was applied to detect the mRNA expression of the MLLPTD fused gene, and further confirm in genomic DNA level.

RESULTSAnalysing MLL-PTD in case 1, the patient's older brother and his younger brother were positive, while his mother and his son were negative. The exon type in case 1 was e9/3 fusion, but in his older brother, it was e9/3 and e11/3 fusion, and in his younger brother, it was e9/3, e10/3, and e11/3 fusion. MLL-PTD in case 2 was negative, but in the patient's older sister was positive, and the exon type was e9/3, e10/3, and e11/3.

CONCLUSIONSThe expression of MLL-PTD was present in cases with acute leukaemia with a single expression type. However, various expression types were detected in their healthy relatives. MLL-PTD can couple with other chromosome aberrations, and its impact on disease prognosis remains to be studied further.

Acute Disease ; Chromosome Aberrations ; Female ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Male ; Myeloid-Lymphoid Leukemia Protein ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

The study was aimed to investigate the subcellular localization of mixed-lineage leukemia (MLL) and Menin proteins, and to explore the interaction between these two proteins. The recombinant eukaryotic cell expression vectors of pcDNA3.1-myc-MLL and pCMV-flag-Menin were constructed respectively, and transfected into the HEK293T cells. Immunofluorescence technique was used to observe the subcellular localization of the two proteins. Co-immunoprecipitation and Western blot methods were applied to evaluate the expression and interaction of the two proteins. The results showed that MLL and Menin proteins could be co-localized in cell nuclei, and the study of binding in vivo revealed that MLL protein could be detected in the immunoprecipitation complex of anti-FLAG, while Menin proteins could also be found in the immunoprecipitation complex of anti-MYC. It is concluded that MLL and Menin proteins co-localized in cell nuclei have same location and the interaction exists between MLL and Menin proteins.
Chromosome Mapping ; DNA-Binding Proteins ; Genetic Vectors ; HEK293 Cells ; Homeodomain Proteins ; Humans ; Leukemia ; genetics ; Myeloid-Lymphoid Leukemia Protein ; genetics ; Protein Interaction Mapping ; Proto-Oncogene Proteins ; genetics ; Transfection

Chromosomal translocations of the human mixed-lineage leukemia (MLL) gene have been analyzed for more than 20 yr at the molecular level. So far, we have collected about 80 direct MLL fusions (MLL-X alleles) and about 120 reciprocal MLL fusions (X-MLL alleles). The reason for the higher amount of reciprocal MLL fusions is that the excess is caused by 3-way translocations with known direct fusion partners. This review is aiming to propose a solution for an obvious problem, namely why so many and completely different MLL fusion alleles are always leading to the same leukemia phenotypes (ALL, AML, or MLL). This review is aiming to explain the molecular consequences of MLL translocations, and secondly, the contribution of the different fusion partners. A new hypothesis will be posed that can be used for future research, aiming to find new avenues for the treatment of this particular leukemia entity.
Alleles ; Chromosomes, Human, X ; Epigenesis, Genetic ; Humans ; Leukemia/classification/*genetics/pathology ; Myeloid-Lymphoid Leukemia Protein/chemistry/genetics ; Protein Structure, Tertiary ; Translocation, Genetic