Objective:To screen for patients with mixed-lineage leukemia (MLL) fusion gene-positive with acute myeloid leukemia (AML), analyze the clinical characteristics and prognosis of patients with AML with positive fusion genes, and report two cases with rare breakpoint sites.Methods:This study included 287 patients with AML (non-acute promyelocytic leukemia) admitted to the Hematology and Oncology Research Center of Harbin First Hospital from October 2021 to October 2023. The cohort involved 157 males and 130 females, with a median age of 48 years (range: 19-80 years). All 287 patients underwent screening for 56 fusion genes and chromosome karyotyping analysis. Fluorescence in situ hybridization (FISH) and RNA seq were further performed on patients with negative fusion genes but positive 11q23.3 chromosomal translocation. Patient observation indicators included remission, recurrence, and others.Results:Among the 287 patients with AML, 15 were positive for the MLL fusion gene, with a positivity rate of 5.2%. Among the 11 types of MLL fusion genes detected, the most prevalent fusion types were MLL-ENL (4 cases), MLL-ELL (4 cases), MLL-AF9 (3 cases), and MLL-AF6 (3 cases). Of the 15 patients with positive MLL fusion gene, 2 demonstrated negative fusion gene while exhibiting positive chromosome and FISH. RNA-seq testing in these two patients revealed an uncommon breakpoint in the MLL fusion gene and a novel breakpoint fusion site, respectively. Complete remission (CR) was achieved in 6 patients with positive MLL fusion genes during the first chemotherapy cycle. After two cycles, eight patients achieved CR, with 50% of them experiencing recurrence within 2 months.Conclusion:RNA seq technology is useful for screening fusion genes with unconventional or novel cleavage sites, and patients with positive MLL fusion genes demonstrated a poorer prognosis.

Objective:To screen for patients with mixed-lineage leukemia (MLL) fusion gene-positive with acute myeloid leukemia (AML), analyze the clinical characteristics and prognosis of patients with AML with positive fusion genes, and report two cases with rare breakpoint sites.Methods:This study included 287 patients with AML (non-acute promyelocytic leukemia) admitted to the Hematology and Oncology Research Center of Harbin First Hospital from October 2021 to October 2023. The cohort involved 157 males and 130 females, with a median age of 48 years (range: 19-80 years). All 287 patients underwent screening for 56 fusion genes and chromosome karyotyping analysis. Fluorescence in situ hybridization (FISH) and RNA seq were further performed on patients with negative fusion genes but positive 11q23.3 chromosomal translocation. Patient observation indicators included remission, recurrence, and others.Results:Among the 287 patients with AML, 15 were positive for the MLL fusion gene, with a positivity rate of 5.2%. Among the 11 types of MLL fusion genes detected, the most prevalent fusion types were MLL-ENL (4 cases), MLL-ELL (4 cases), MLL-AF9 (3 cases), and MLL-AF6 (3 cases). Of the 15 patients with positive MLL fusion gene, 2 demonstrated negative fusion gene while exhibiting positive chromosome and FISH. RNA-seq testing in these two patients revealed an uncommon breakpoint in the MLL fusion gene and a novel breakpoint fusion site, respectively. Complete remission (CR) was achieved in 6 patients with positive MLL fusion genes during the first chemotherapy cycle. After two cycles, eight patients achieved CR, with 50% of them experiencing recurrence within 2 months.Conclusion:RNA seq technology is useful for screening fusion genes with unconventional or novel cleavage sites, and patients with positive MLL fusion genes demonstrated a poorer prognosis.

Objective To explore the relationship between WT1 and prognosis of patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), and to evaluate the possibility of WT1 as a potential marker for monitoring the minimal residual disease (MRD). Methods Bone marrow mononuclear cells from 58 patients with primary AML, 32 patients with primary ALL, 40 patients with AML-complete remission (CR), 28 patients with ALL-CR and 31 patients with trilineage hyperplasia (control group) were collected. Real-time fluorescent quantitative PCR method was used to detect the expression of WT1 in all patients. The expression threshold of WT1 in each group was established. WT1 copy number/ABL copy number ratio×100%denotes the relative expression level of WT1 gene. Results Median relative expression level of WT1 in the control patients was much lower than that in primary AML patients [0.026%(0-0.240%) vs. 20.880 % (3.550 %-48.500 %), Z=-7.74, P<0.000 1]. Relative expression level of WT1 between AML-CR patients [0.102%(0-5.380%)] and primary AML patients had significant difference (Z=-8.34, P<0.000 1). Moreover, the relative expression level rate of the first course in AML patients with higher WT1 expression level (>20.880 %) was 60.7 % (17/28), while the CR rate was 76.7 % (23/30) in those with lower WT1 expression. WT1 expression was increased dramatically in recurrent AML patients. Relative expression level of WT1 was significantly higher in primary ALL patients [0.350 % (0.021 %-10.780 %)] compared with that in the control group Z=-2.58, P<0.05. There was no significant difference in relative expression level of WT1 between ALL and ALL-CR patients [0.038 % (0-2.800 %), P=0.065]. Conclusion WT1 expression level in AML patients is relatively high, which could be used as an effective index of prognosis evaluation and MRD monitoring for AML patients, but not for ALL patients.

Objective Estahlished the method to detect different transcripts of EVI1 gene expression with quantitative PCR and study the expression patterns of EVI1 gene in different leukemia groups to investigate the association between EVI1 gene expression and the incidence and prognosis of leukemia.Methods 60 cases acute myeloid leukemia (AML) and 9 cases normal control were detected in the study,37 cases were male and 32 cases were female,age 10-70 years,median age 42 years,M3 36 cases,M2 16 cases and M4 8 cases according to FAB classification criteria,control samples of nine cases were normal healthy people.Using the quantitative PCR (Taq Man probe) to detect the expression of different transcripts of EVI1 gene.The t test was used to detect the expression difference among different leukemia groups.Results ABL gene was used as internal reference,relative changes of EVI1 gene expression level were detected by EVI1/ABL.In all the control patients,EVI1 gene of different transcription of this expression were detected,expression level of EVI1 gene different transcription was significant with the difference (P ＜ 0.05),transcription 2 and 5 (the same primers) were the lowest,followed for transcription 1 and 6,expression of transcription 3 was the highest.The expression levels of transcripts 2 and 5,1,6,3 were nagative,0.005,0.050 and 0.512 respectively in healthy control samples.In addition,the EVI1 gene expression was negatively correlated with expression of the fusion gene AML-ETO and CBFB-MYH11 in AML.Conclusion The study established a stable,fast and accurate method to detect the expression of EVI1 gene.

Objective To delineate the potency of YC-1 on the proliferation,apoptosis,cell cycle and the protein expression of Caspase-3,-8,-9 in U937 and THP-1 leukemia cell lines.Methods MTT assay was performed to detect proliferation.Flow cytometry was used to measure the apoptosis and cell cycle.The expression of Caspase-3,-8 and-9 were detected by Western blot.Results The MTT assay showed that cell proliferation was inhibited in a concentration-dependent manner in 1.0,3.0,10.0 μmol/L YC-l-treated U937 and THP-1 cells.The survival rates for YC-1 after 24 h in U937 cells were (76.5±4.4) ％,(68.7±6.8) ％,(60.9±13.2) ％ respectively and (94.1±1.4) ％,(81.4±2.0) ％,(72.7±3.0) ％ respectively in THP-1 cell,compared with the control group (100 ％),there were significant differences (F =15.870,126.629,P ＜ 0.01).The apoptosis rates for 1.0,3.0,10.0 μmol/L YC-1 after 24 h were (40.7±1.0) ％,(55.6±2.3) ％,(71.8±1.5) ％respectively in U937 cells and (34.6±2.0) ％,(50.3±3.5) ％,(59.6±4.6) ％ respectively in THP-1 cells.With the control group (4.7±1.4) ％,(1.8±1.0) ％,there were significant difference (F =937.229,200.447,P ＜ 0.01).However,there was no significant difference for cell cycle.In addition,Cleaved Caspase-8 and Cleaved Caspase-3 expression after 1.0,3.0,10.0 μmol/L YC-1 treated for 24 h were significantly higher than control,but the expression of Caspase-9 did not appear significant change in U937 cells.As the same concentration and time point,Cleaved Caspase-3 expression increased with no change of Caspase-9 or Caspase-8 in THP-1 cells.Conclusion YC-1 effectively suppress the proliferation with little effect on cell cycle,but induce the apoptosis,have no effect on cell cycle,and the mechanism of apoptosis may be related to the Caspase activation in U937 and THP-1 cell lines.

Recent studies indicated that epigenetic abnormality is the important molecular mechanism in leukemia. The change of epigenetic modification occurs in most kinds of leukaemia. Based on the epigenetic modification, the therapies of leukemia with hypomethylating agents and histone deaeetylases inhibitors, which are different from traditional chemotherapy are applied in the treatment of leukemia at beginning. The aim of this article is to summarize the recent advances of DNA methylation and histone modification in leukaemia occurrence, treatment and prognosis.