OBJECTIVE: To assess the influence of FLT3 expression on the prognosis of patients with acute myeloid leukemia (AML) by cell experiment and clinical data analysis. METHODS: Models for FLT3 over-expression and interference-expression in AML cells were constructed. The level of BAK gene expression and its protein product was determined, along with the proliferation and apoptosis of leukemia cells. FLT3 gene expression and FLT3-ITD variant were determined among patients with newly diagnosed AML. RESULTS: Compared with the interference-expression group, the level of BAK gene expression and its protein in FLT3 over-expression AML cells was significantly lower (P < 0.001), which also showed significantly faster proliferation (P < 0.001) and lower rate of apoptosis (P < 0.001). The expression level of FLT3 gene among patients with newly diagnosed AML was also significantly higher compared with the healthy controls (P < 0.001). The FLT3 gene expression of FLT3-ITD positive AML patients was higher than that of FLT3-WT patients (P = 0.002). Survival analysis showed that AML patients with high FLT3 expression in the medium-risk group had a lower complete remission rate and overall survival rate compared with those with a low FLT3 expression (P < 0.001). CONCLUSION Over-expression of FLT3 may influence the course of AML by promoting the proliferation of leukemia cells and inhibiting their apoptosis, which in turn may affect the prognosis of patients and serve as a negative prognostic factor for AML.
Humans ; Apoptosis/genetics* ; Data Analysis ; Leukemia, Myeloid, Acute/genetics* ; Gene Expression ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To explore the efficacy of venetoclax (VEN) plus azacitidine (AZA) in patients with FLT3-ITD mutated relapsed/refractory acute myeloid leukemia (FLT3-ITD^mut R/R AML) and analyze the molecular genetic characteristics of the patients. METHODS: Clinical baseline characteristics and follow-up data of 16 R/R AML patients treatd with VEN plus AZA in the hematology department of Shenzhen Second People's Hospital from November 2018 to April 2021 were collected. Leukemia related genes were detected by next-generation sequencing(NGS) or PCR. The relationship between the efficacy of VEN plus AZA and molecular genetics characteristics of patients with FLT3-ITD^mut R/R AML were analyzed. RESULTS: 14.3% (1/7) of the patients in FLT3-ITD^mut group and 22.2% (2/9) of the patients in FLT3-ITD^wt group achieved complete remission (CR)/CR with incomplete blood count recovery (CRi), respectively, with no significant difference (P=0.69). There was no significant difference in overall response rate (ORR) (CR/CRi+PR) between FLT3-ITD^mut group and FLT3-ITD^wt group [42.9%(3/7) vs 44.4%(4/9), P=0.95], too. The median overall survival (OS) time of FLT3-ITD^mut patients was significantly shorter than that of FLT3-ITD^wt patients (130 vs 300 days, respectively) (P =0.02). Co-existing mutations of FLT3-ITD and IDH1 were detected in one patient who achieved CR. Co-existing mutations of FLT3-ITD and SF3B1 were found in one patient who achieved PR. Three FLT3-ITD^mut R/R AML patients accompanied with NPM1 mutation had no response to VEN plus AZA. CONCLUSION VEN plus AZA showed a certain effect on patients with FLT3-ITD^mut R/R AML. To improve OS of the patients, bridging transplantation is need. IDH1 and SF3B1 mutations might predict that patients with FLT3-ITD^mut R/R AML have treatment response to VEN plus AZA, while the combination of NPM1 mutation may indicate poor response.
Humans ; Nucleophosmin ; Prognosis ; Leukemia, Myeloid, Acute/genetics* ; Mutation ; Azacitidine/therapeutic use* ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To observe the clinical significance of translocator proteins (TSPO) gene in the treatment of FLT3-ITD/DNMT3A R882 double-mutated acute myeloid leukemia (AML). METHODS: Seventy-six patients with AML hospitalized in the Department of Hematology of the Affiliated People's Hospital of Ningbo University from June 2018 to June 2020 were selected, including 34 patients with FLT3-ITD mutation, 27 patients with DNMT3A R882 mutation, 15 patients with FLT3-ITD/DNMT3A R882 double mutation, as well as 19 patients with immune thrombocytopenia (ITP) hospitalized during the same period as control group. RNA was routinely extracted from 3 ml bone marrow retained during bone puncture, and TSPO gene expression was detected by transcriptome sequencing (using 2-deltadeltaCt calculation). RESULTS: The expression of TSPO gene in FLT3-ITD group and DNMT3A R882 group at first diagnosis was 2.02±1.04 and 1.85±0.76, respectively, which were both higher than 1.00±0.06 in control group, but the differences were not statistically significant (P=0.671, P=0.821). The expression of TSPO gene in the FLT3-ITD/DNMT3A R882 group was 3.98±1.07, wich was significantly higher than that in the FLT3-ITD group and DNMT3A R882 group, the differences were statistically significant (P=0.032, P=0.021). The expression of TSPO gene in patients who achieved complete response after chemotherapy in the FLT3-ITD/DNMT3A R882 group was 1.19±0.87, which was significantly lower than that at first diagnosis, and the difference was statistically significant (P=0.011). CONCLUSION TSPO gene may be used as an indicator of efficacy in FLT3-ITD /DNMT3A R882 double-mutated AML.
Humans ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; DNA Methyltransferase 3A ; Mutation ; Leukemia, Myeloid, Acute/drug therapy* ; Nucleophosmin ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics* ; Receptors, GABA/therapeutic use*

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic tumor originated from hematopoietic stem cells. FLT3 is an important receptor tyrosine kinase in cell signal transduction pathway and one of the common mutated genes in AML. AML patients with FLT3-ITD mutation have a poor prognosis and tendency to relapse. Therefore, early identification of FLT3 gene mutation and selection of appropriate treatment are particularly important. Currently, the small moleculetargeted drugs have been new treatment methods for AML patients with FLT3-ITD mutation, but accompanied drug resistance need to be solved. This paper reviews the mechanism of FLT3 mutation, the clinical significance of FLT3 mutation in AML, FLT3 inhibitors and drug resistance mechanism.
Humans ; Mutation ; Protein Kinase Inhibitors/therapeutic use* ; Signal Transduction ; Receptor Protein-Tyrosine Kinases/therapeutic use* ; Leukemia, Myeloid, Acute/drug therapy* ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To explain the clinicobiological heterogeneity of NPM1 mutated (NPM1^mut) acute myeloid leukemia (AML) by analyzing the association between next-generation sequencing (NGS) profiles and MICM characteristics in patients with this AML subtype. METHODS: Data of 238 NPM1^mut patients with available NGS information on 112 genes related to blood disease was collected, and χ² test and nonparametric test were used to analyze the distribution association between NGS-detecting mutations and conventional MICM parameters. RESULTS: In entire NPM1^mut cohort, totaling 240 NPM1 mutation events were identified, of whom 10 (10/240, 4.2%) were missense mutations, which did not involve any W288 or W290 locus and were found exclusively in NPM1^mut/FLT3-ITD^- group. All but one of these missense mutations (9/10, 90%) were accompanied by AML subtype-defining recurrent cytogenetic or molecular abnormalities, of which 7 cases were in the low risk and 2 in the high risk. NPM1^mut occurred solely as an insertion/deletion (indel) type in the NPM1^mut/FLT3-ITD⁺ group. The incidence of favorable plus unfavorable karyotypes in NPM1^mut/FLT3-ITD^- group was higher than in NPM1^mut/FLT3-ITD⁺ group (6.4% vs. 0, P=0.031). The positive rates of CD34 and CD7 in NPM1^mut/FLT3-ITD⁺ group were significantly higher than in NPM1^mut/FLT3-ITD^- group (CD34: 47.9% vs. 20.6%, P<0.001; CD7: 61.5% vs. 29.9%, P<0.001). Logistic analysis showed that FLT3-ITD independently predicted for CD34⁺ and CD7⁺ [odds ratio (OR)=5.29, 95%CI: 2.64-10.60, P<0.001; OR=3.47, 95%CI: 1.79-6.73, P<0.001; respectively]. Ras-pathway mutations independently predicted for HLA-DR⁺ (OR=4.05, 95%CI: 1.70-9.63, P=0.002), and KRAS mutation for MPO^- (OR=0.18, 95%CI: 0.05-0.62, P=0.007). TET2/IDH1 mutations independently predicted for CD34^- and CD7^- (OR=0.26, 95%CI: 0.11-0.62, P=0.002; OR=0.30, 95%CI: 0.14-0.62, P=0.001; respectively), and MPO⁺ (OR=3.52, 95%CI: 1.48-8.38, P=0.004). DNMT3A-R882 independently predicted for CD7⁺ and HLA-DR⁺ (OR=3.59, 95%CI: 1.80-7.16, P<0.001; OR=13.41, 95%CI: 4.56-39.45, P<0.001; respectively), and DNMT3A mutation for MPO^-(OR=0.35, 95%CI: 1.48-8.38, P=0.004). CONCLUSION Co-existing FLT3-ITD in NPM1^mut AML independently predicts for CD34⁺ and CD7⁺, co-existing Ras-pathway mutation for HLA-DR⁺ and MPO^-, co-existing TET2/IDH1 mutation for CD34^-, CD7^-, and MPO⁺, and co-existing DNMT3A mutation for HLA-DR⁺, CD7⁺, and MPO^-, thereby providing a new mechanism explanation for the immunophenotypic heterogeneity of these AML patients.
High-Throughput Nucleotide Sequencing ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Mutation ; Nuclear Proteins/genetics* ; Nucleophosmin ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: Two sgRNAs transfected FLT3-ITD⁺AML cell line MV411 with different binding sites were introduced into CRISPR/cas9 to obtain MV411 cells with miR-155 gene knockout. To compare the efficiency of miR-155 gene knockout by single and double sgRNA transfection and their effects on cell phenotypes. METHODS: The lentiviral vectors were generated containing either single sgRNA or dual sgRNAs and packaged into lentivirus particles. PCR was conducted to measure gene editing efficiency, and miR-155 expression was evaluated by qPCR. CCK-8 assay was used to evaluate the cell proliferation, and calculate drug sensitivity of cells to adriamycin and quizartinib. Annexin V-APC/7-AAD staining was used to label cell apoptosis induced by adriamycin and quizartinib. RESULTS: In the dual sgRNAs transfected cells, a cleavage band could be observed, meaning the success of gene editing. Compared with the single sgRNA transfected MV411 cells, the expression level of mature miR-155-5p was lower in the dual sgRNA transfected cells. And, dual sgRNA transfected MV411 were more sensitive to adriamycin and quizartinib with lower IC₅₀ and higher apoptosis rate. CONCLUSION The inhibition rate of miR-155 gene expression transfected by dual sgRNA is higher than that by single sgRNA. Dual sgRNA transfection can inhibit cell proliferation, reverse drug resistance, and induce apoptosis more significantly. Compared with single sgRNA transfection, dual sgRNA transfection is a highly efficient gene editing scheme.
CRISPR-Cas Systems ; Doxorubicin/pharmacology* ; Drug Resistance ; Gene Editing ; Humans ; Leukemia, Myeloid, Acute/genetics* ; MicroRNAs/genetics* ; RNA, Guide/genetics* ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To investigate the coexisting mutations and clinical significance of Homo sapiens neuroblastoma RAS viral oncogene homolog (NRAS) gene in acute myeloid leukemia (AML) patients. METHODS: High-throughput DNA sequencing and Sanger sequencing were used to detect 51 gene mutations. The occurrence, clinical characteristics and treatment efficacy of coexisting genes with NRAS were investigated. RESULTS: A total of 57 NRAS mutations (17.5%) were detected in 326 patients with AML. Compared with the patients in NRAS non-mutation group, patients in the mutant group were younger (P=0.018) and showed lower platelet count (P=0.033), but there was no significant difference in peripheral leukocyte count, hemoglobin, and sex. For FAB classification, NRAS mutation and M2 subtype showed mutually exclusive (P=0.038). Among 57 patients carried with NRAS mutation, 51 (89.5%) patients carried with other gene mutations, 25 (43.9%) carried with double gene mutations, 10 (17.5%) carried with 3 gene mutations, and 16 (28.1%) corried with ≥ 4 gene mutations. The most common coexisting gene mutation was KRAS (24.6%, 14/57), followed by FLT3-ITD (14.0%, 8/57), RUNX1 (12.3%, 7/57), NPM1 (10.5%, 6/57), PTPN11 (10.5%, 6/57), DNMT3A (10.5%, 6/57) and so on. The age (P=0.013, P=0.005) and peripheral platelet count (P=0.007, P=0.021) of patients with NPM1 or DNMT3A mutations were higher than those of the patients with wild type, but there was no significant difference in peripheral leukocyte count and hemoglobin. Also, there was no significant difference in age, peripheral leukocyte count, hemoglobin, and peripheral platelet count between the patients in KRAS, FLT3-ITD, RUNX1 or PTPN11 mutant group and the wild group. Patients with FLT3-ITD mutations showed a lower complete remission (CR) rate (P=0.044). However, there was no significant difference in CR rate between the patients with KRAS, NPM1, RUNX1, PTPN11 or DNMT3A mutations and the wild group. The CR rate of the patents with single gene mutation, double gene mutations, 3 gene mutations, and≥ 4 gene mutations were decreased gradually, and there was no significant difference in CR rate between pairwise comparisons. CONCLUSION The mutation rate of NRAS mutation is 17.5%, 89.5% of AML patients with NRAS mutation coexist with additional gene mutations. The type of coexisting mutations has a certain impact on clinical characteristics and CR rate of patients with AML.
Core Binding Factor Alpha 2 Subunit/genetics* ; GTP Phosphohydrolases/genetics* ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Membrane Proteins/genetics* ; Mutation ; Nucleophosmin ; Prognosis ; Proto-Oncogene Proteins p21(ras)/genetics* ; fms-Like Tyrosine Kinase 3

The clinical therapeutic regimen for acute myeloid leukemia (AML) is not significantly different between adults and children, which is mostly based on IA (idarubicin and cytosine arabinoside) induction chemotherapy. With the rapid development of sequencing technique, people's understandings towards the molecular and biological abnormalities of AML are increasing, diverse AML gene mutation-based targeted drugs have been rapidly developed and applied. In this review, several commonly gene mutations in AML (such as FLT3, NPM1 and C/EBPA) was described, and the therapeutic effects and differences of targeted drugs that used in clinical treatment or had been reported (like tyrosine kinase inhibitor, IDH1 mutation inhibitor and epigenetic modification inhibitor) in child and adult AML patients were summrized.
Adult ; Child ; Cytarabine ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Mutation ; Myeloproliferative Disorders ; Nuclear Proteins/genetics* ; Nucleophosmin ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To investigate the effects of paclitaxel, quizartinib and their combination on proliferation, apoptosis and FLT3/STAT5 pathway of human leukemia cell line MV4-11 (FLT3-ITD+). METHODS: MV4-11 cells were treated with paclitaxel and quizartinib at different concentrations for 24 h, 48 h and 72 h, respectively, and then the two drugs were combined at 48 h to compare the inhibition of proliferation, the apoptosis rate was detected by flow cytometry, the expression of FLT3 and STAT5 mRNA was determined by fluorescence quantitative PCR, and the protein expression of FLT3, p-FLT3, STAT5 and p-STAT5 was determined by Western blot. RESULTS: Different combination groups of paclitaxel and quizartinib had synergistic inhibitory effect. The cell survival rate in the combination group was significantly lower than that in the single drug group (P<0.05). The cell apoptosis rate in the combination group was significantly higher than that in the single drug group (P<0.001). The expression of FLT3 mRNA in combination group was significantly higher than that in two single drugs (P<0.01). The expression of STAT5 mRNA in combination group was significantly higher than that in quizartinib group (P<0.001); increased compared with paclitaxel group, but there was no statistical significance. The expression level of p-FLT3、p-STAT5 protein in the combination group was significantly lower than that in the single drug group (P<0.05, P<0.05). CONCLUSION Paclitaxel combined with quizartinib can synergistically inhibit the proliferation of MV4-11 cell line and promote the apoptosis of MV4-11 cell line by inhibiting the activity of FLT3/STAT5 pathway.
Apoptosis ; Benzothiazoles ; Cell Line, Tumor ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Paclitaxel/therapeutic use* ; Phenylurea Compounds ; RNA, Messenger ; STAT5 Transcription Factor/pharmacology* ; Signal Transduction ; fms-Like Tyrosine Kinase 3

OBJECTIVE: To investigate the characteristics of gene mutation in elderly patients with acute myeloid leukemia (AML) and its effect on prognosis. METHODS: The clinical and laboratorial characteristics of 54 AML patients (≥60 years old) in Department of Hematology, Tangdu Hospital were analyzed retrospectively during April 2016 to October 2019. Thirty-four AML/myelodysplastic syndrome/myeloproliferative neoplasm related mutant genes were detected by second-generation sequencing technology, and their clinical characteristics, treatment effect, and influence on prognosis were analyzed. RESULTS: All the patients received DAC+CAG induction treatment, after 1-2 couses of treatment, 36 cases (66.7%) achieved complete response, with a total effective rate of 75.9%, and the median survival time was 17 months. The most frequent mutant genes were TET2 (33.3%), CEBPA (31.5%), DNMT3A (18.5%), ASXL1 (16.7%), NRAS (14.8%), RUNX1 (14.8%), FLT3-ITD (12.9%), TP53 (12.9%), NPM1 (12.9%), and IDH2 (12.9%). Among 7 patients with TP53 mutation, 6 cases obtained complete response after 1-2 courses of induction treatment, but there was no statistically significant difference in the effect on prognosis. Patients with FLT3-ITD and NRAS mutations had shorter overall survival time compared with who had no mutation (P=0.47, P=0.48). Multivariate analysis showed that FLT3-ITD and NRAS mutations were poor prognostic factors. CONCLUSION The incidence of TET2 gene mutation is high in elderly AML patients. AML patients with TET2 and TP53 mutations may benefit from Decitabine-based chemotherapy. However, patients with FLT3-ITD and NRAS mutations have a short survival time, and may have a poor prognosis.
Aged ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Middle Aged ; Mutation ; Nucleophosmin ; Prognosis ; Retrospective Studies ; fms-Like Tyrosine Kinase 3