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 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*

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 analyze the predictive value of acute phase proteins (APPs) on the prognosis of patients with acute myeloid leukemia (AML). METHODS: 293 AML patients who met the study requirements from January 2015 to April 2021 were collected, their clinical characteristics and pre-treatment APPs levels ［including albumin (ALB), fibrinogen (FIB), C-reactive protein (CRP), Ferritin (FER)］ were followed up and investigated. Pearson correlation coefficient was used to analyze the correlation between APPs. Logistic regression was used to analyze the risk factors for mortality in AML patients. ROC curve was used to analyze the predictive value of APP for mortality in AML patients, and Kaplan-Meier survival analysis was used to compare the effect of APPs on complete remission (CR) rate, overall survival (OS), disease-free survival (DFS), and progression-free survival rate (PFS) of AML patients. RESULTS: Pearson correlation analysis showed that there were negative correlations between ALB and CRP (r=-0.134, P=0002), as well as ALB and FER (r=-0.148, P=0.001). There were correlations between FER and CRP (r=0361, P＜0.001), as well as FER and FIB (r=0.293, P＜0.001). Logistic regression analysis showed that advanced age (>50 years) (OR=1.87, 95% CI=1.25-2.15, P＜0.001), relapse after treatment (OR=2.11, 95% CI=111-3.18, P=0.003), FLT3-ITD mutation (OR=2.59, 95% CI=1.10-4.12, P＜0.001), CRP≥524 mg/L (OR=1.21, 95% CI=1.02-2.14, P=0.024), CFA (CFA=CRP*FIB/ ALB)≥3 (OR=2.41, 95% CI=1.65-6.47, P＜0.001), and FER≥1145.58 mg/ml (OR=1.67, 95% CI=1.15-3.75, P＜0.001) were the risk factors for the survival of AML patients. ROC curve analysis showed that FER (AUC=0.752, 95% CI=0.681-0823, P＜0.001, the best cut-off value=1220.56 mg/ml) and CFA (AUC=0.804, 95% CI=0.741-0.868, P＜0.001, the best cut-off value=3.00) had higher predictive value for the survival of AML patients. The remission rate, PFS, DFS, and OS in the low CFA group (CFA≤3) were significantly higher than those in the high CFA group (CFA＞3), and the overall mortality rate was lower than that in the high CFA group; the remission rate, PFS, DFS, and OS in the low FER group (FER≤1220.56 mg/ml) were significantly higher than those in the high FER group (FER＞1220.56 mg/ml), while the overall mortality rate was lower than that in the high FER group, and the difference is statistically significant. CONCLUSION The CFA value and FER level before treatment in AML patients can independently predict the prognosis of patients, and high levels of CFA and FER are associated with poor prognosis of AML patients.
Acute-Phase Proteins/therapeutic use* ; C-Reactive Protein ; Disease-Free Survival ; Ferritins/therapeutic use* ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Middle Aged ; Mutation ; Prognosis ; Remission Induction ; Retrospective Studies ; fms-Like Tyrosine Kinase 3

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

OBJECTIVE: To investigate the clinical characteristics of RAS gene mutations in patients with acute myeloid leukemia (AML). METHODS: 43 myeloid gene mutations were detected using next-generation sequencing (NGS) in 180 patients with AML who were first diagnosed between May 2011 and February 2021. The molecular and clinical features of RAS gene mutations and their effects on efficacy and survival of patients were retrospectively analyzed. RESULTS: Among 180 AML patients, the proportion of mutations in RAS pathway-related genes were NRAS (14.4%), KRAS (2.2%), FLT3-ITD (13.8%), PTPN11 (7.7%), KIT (5.0%), FLT3-TKD (3.8%) and CBL (2.7%). Seventy-three (40.6%) AML patients had gene mutations associated with the RAS pathway.The number of peripheral blood white blood cells and the proportion of bone marrow primitive juvenile cells in patients with NRAS/KRAS gene mutation were higher than those of patient with RAS wild-type, the difference was statistically significant (P<0.05). NRAS/KRAS gene mutations were significantly associated with the CBL gene mutation(r=0.287). In young AML patients (age <60 years), there were no significant differences in complete response rate (CR), progression-free survival (PFS), and overall survival (OS) between patients with RAS gene mutation and those with wild-type(P>0.05). In elderly AML patients (age≥60 years), PFS and OS in RAS mutants were significantly lower than those in wild-type patients(P<0.05). CONCLUSION In AML patients, RAS gene mutation is relatively common, and RAS gene mutation is associated with clinical characteristics and efficacy of patients, and may be a molecular marker of poor prognosis for elderly AML.
Aged ; Genes, ras ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Middle Aged ; Mutation ; Nucleophosmin ; Prognosis ; Proto-Oncogene Proteins p21(ras)/genetics* ; Retrospective Studies ; 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*