Development and application of a highly sensitive method for detection of mutation of FMS-like tyrosine kinase-3-tyrosine kinase domain of acute myeloid leukemia / 中国生物制品学杂志

@#ObjectiveTo develop a highly sensitive method for detection of mutation of FMS-like tyrosine kinase-3-tyrosine kinase domain(FLT3-TKD)of acute myeloid leukemia(AML)and apply to the monitor of minimal residual disease(MRD).MethodsRecombinant plasmids containing wild FLT3 and mutant FLT3-D835Y were constructed respectively and mixed at certain ratios.The obtained standard plasmids with mutation rates of 50%,1%,0.1% and 0% respectively were determined by restriction fragment length polymorphism(RFLP)in combination with Sanger method.The plasmid DNA standards and blood DNA standards,at various FLT3-D835Y mutation rates,were determined by the developed method to verify the sensitivity.The genomic DNA samples of patients with AML before and after treatment were determined by the developed method to monitor the MRD.ResultsSequencing proved that both the recombinant plasmids containing wild FLT3 and mutant FLT3-D835Y were constructed correctly.The sensitivity of developed method increased to 0.1% through Sanger method combined with digestion with EcoR Ⅴ/Xho Ⅰ and recovery of mutant fragments in determination of purified plasmid DNA and collected blood DNA samples.MRD was detected in the peripheral blood sample of a patients with AML in complete remission period by the developed method but not by Sanger method.ConclusionA highly sensitive method for detection of FLT3-TKD mutation was developed,which was of an important clinical significance in guiding the treatment of AML and monitoring the MRD in complete remission period.

Clinical application progress of novel targeted drug gilteritinib in treatment of acute myeloid leukemia with FLT3 mutation / 白血病·淋巴瘤

Acute myeloid leukemia (AML) patients with FLT3 mutation have a high risk of recurrence and poor prognosis. The first generation of drugs targeting FLT3 represented by sorafenib show poor selectivity and efficacy in the treatment of AML, whereas the new second-generation FLT3 inhibitors represented by gilteritinib have a stronger inhibitory effect on FLT3, higher specificity and lower off-target toxicity, which greatly improves the outcomes of AML patients with FLT3 mutation. This article reviews the action mechanism and the clinical progress of gilteritinib.

A clinicopathological experience in acute myeloid leukemia: Effects of clinical data and status of FLT3, CEBPA and NPM1 on prognosis

Background: The purpose of the study was to analyze the expression of nucleophosmin (NPM1), CCAT/enhancer-binding protein alpha (CEBPA), and FMS-like tyrosine kinase 3 (FLT3) with immunohistochemistry and evaluate the relationship with clinicopathologic data with special emphasis on prognosis in bone marrow biopsy specimens diagnosed with acute myeloid leukemia (AML). Materials and Methods: Bone marrow biopsies of 104 patients who were diagnosed with AML were re-evaluated for diagnosis and subclassification. Immunohistochemically, anti-NPM1, anti-CEBPA, and anti-FLT3 antibodies were applied to slides prepared from formalin-fixed paraffin-embedded tissues. Sixty-three of these patients had their follow-up in our institutional hematology clinic and these patients' clinical, biochemical, and radiological data were obtained and analyzed from patient files. These data were analyzed with survival times statistically. Results: Except for age, no significant effect of clinical data on prognosis was detected. Immunohistochemical results were also statistically compared with clinical data. No correlation was found between overall survival and disease-free survival with the expression of anti-CEBPA or anti-NPM1 antibodies. However, immunohistochemical reactivity for anti-FLT3 antibody was found to be a poor prognostic factor and statistically significant. Also, when the expression of FLT3 was analyzed with that of NPM1 or CEBPA, a correlation (dependent on the expression of FLT3) was found with disease-free survival. Conclusions: FLT3 is an independent prognostic factor for AML. CEBPA and NPM1 should be considered as good prognostic factors only in the absence of FLT3 abnormalities.

Efficacy of chemotherapy combined with sorafenib for FLT3-ITD-positive acute myeloid leukemia / 中国基层医药

Objective:To investigate the effect of chemotherapy combined with sorafenib on the prognosis of FLT3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukemia and to find a more effective treatment.Methods:The clinical data of 60 patients who were newly diagnosed with acute myeloid leukemia and who received treatment in The Second Affiliated Hospital of Qiqihar Medical University from January 2015 to January 2017 were retrospectively analyzed. The patients were divided into three groups according to whether they were positive for FLT3-ITD and the treatment method they used. The observation group (FLT3-ITD-positive, n = 19) were treated with sorafenib based on routine chemotherapy. The control group 1 (FLT3-ITD-positive, n = 21) was treated only with routine chemotherapy. The control group 2 (FLT3-ITD-negative, n = 20) was treated only with routine chemotherapy. After the first and fourth courses of treatment, clinical efficacy was compared among the three groups. Results:After the first course of treatment, the complete remission rate in control group 2 was 50.0% (10/20), which was significantly higher than 15.8% (3/19) in the observation group and 4.8% (1/21) in the control group 1 ( H = 13.39, P < 0.05). After the fourth course of treatment, the complete remission rate in the observation group, control group 2, and control group 1 was 63.2% (12/19), 60.0% (12/20), and 4.8% (1/21), respectively, and the differences were statistically significant ( H = 19.21, P < 0.05). Four-year follow-up results showed that the median survival time in the observation group, control group 1, and control group 2 was 36.63, 24.15, and 45.00 months respectively. The event-free survival in the observation group, control group 1, and control group 2 was 18.00, 9.82, and 24.90 months, respectively. The median survival time and the event-free survival in the control group 2 were significantly longer than those in the observation group and control group 1 ( χ2 = 19.93, 23.04, both P < 0.001). Conclusion:Chemotherapy combined with sorafenib for treating newly-diagnosed FLT3-ITD-positive acute myeloid leukemia can provide comprehensive benefits and have advantages for survival over chemotherapy without sorafenib and chemotherapy alone.

Geritinib in the targeted therapy of acute myeloid leukemia with FLT3 mutation: report of 5 cases and review of literature / 白血病·淋巴瘤

Objective:To investigate the efficacy and safety of geritinib in the treatment of acute myeloid leukemia (AML) with FLT3 mutation.Methods:The clinical data of 5 AML patients with FLT3 mutation who were diagnosed in the University of Hong Kong-Shenzhen Hospital, Shenzhen People's Hospital, Shenzhen Second People's Hospital, Shenzhen University General Hospital from March 2020 to April 2021 were retrospectively analyzed. Relapsed patients concurrently received two- or three-drug chemotherapy combined with geritinib. Blood routine was checked once a week; liver function and renal function were checked once every 2 weeks during treatment. Bone marrow puncture was performed once every 1 to 3 months to monitor the bone marrow morphology, minimal residual disease (MRD) and FLT3 mutation expression levels. The efficacy, side effects, overall survival of these patients were analyzed after treatment with geritinib.Results:The white blood cell was increased in all the 5 patients at the initial diagnosis. FLT3 mutations analysis showed FLT3-internal tandem duplication (ITD) (3 cases) and FLT-3 tyrosine-kinase domain (TKD) (2 cases). Among 5 patients, 1 patient was relapse-free with maintenance therapy of oral geritinib after hematological stem cell transplantation (HSCT) for 60 days; among other 4 relapsed and refractory patients, 1 female patient after pregnancy relapsed after transplantation and then achieved complete remission followed by the maintenance therapy with geritinib after oral geritinib, 1 16-year-old patient achieved treatment outcome close to the complete remission after treatment with geritinib, 1 patient achieved complete remission after treatment with geritinib, and then underwent haplo-HSCT followed by the maintenance therapy with geritinib and the other 1 relapsed patient achieved complete remission after treatment with geritinib. After transplantation, 3 patients receiving maintenance treatment of geritinib did not relapse. The main side effects included anemia, decreased neutrophil count, rash, and increased aminotransferase. The median follow-up time of 5 patients was 15 months (6-20 months). All 5 cases survived until the last follow-up in November 2021 and 4 patients were disease-free.Conclusions:Relapsed and refractory AML patients with FLT3 mutation can achieve complete remission after treatment with geritinib and get a chance for transplantation. Geritinib may reduce the risk of recurrence after transplantation and improve survival rate. No serious side effects occur in geritinib treatment.

Coexisting gene mutations of FLT3-ITD mutation in acute myeloid leukemia / 白血病·淋巴瘤

Objective:To explore the coexisting gene mutations of FLT3-ITD mutation and its association with partial clinical parameters in acute myeloid leukemia (AML).Methods:The clinical data of 236 newly diagnosed AML outpatients and hospitalized patients of Changzhou No.2 People's Hospital and the Second People's Hospital of Wuxi between December 2012 and August 2019 were retrospectively analyzed. Genome DNA-polymerase chain reaction (PCR) combined with Sanger sequencing was used to detect FLT3-ITD mutations, and 51 tumor target gene mutations in patients with FLT3-ITD mutations were detected by using high-throughput DNA sequencing combined with Sanger sequencing.Results:Among 236 AML patients, FLT3-ITD mutations were found in 71 cases (30.1%). About 97.2% (69/71) patients with FLT3-ITD mutations were accompanied by additional mutations, of which 19 patients harbored double coexisting genes mutations, 24 patients harbored 3 coexisting genes mutations and 26 patients harbored ≥ 4 coexisting genes mutations. The most common coexisting genes mutations were NPM1 (55 cases, 77.5%), followed by DNMT3A (36 cases, 50.7%), TET2 (9 cases, 12.7%), CEBPA (5 cases, 7.0%), IDH1 (4 cases, 5.6%) and NRAS (4 cases, 5.6%). In FLT3-ITD mutation group, the hemoglobin level of patients with DNMT3A mutation type was lower than that of those with DNMT3A wild type ( t = -2.37, P = 0.020); the hemoglobin level of patients with NPM1 mutation type was higher than that of those with NPM1 wild type ( t = 2.04, P = 0.045). The platelet in patients with 3 mutations and ≥ 4 mutations was higher than that in those with double mutations ( χ2 = 7.72, P = 0.021). After chemotherapy in 71 patients, the curative effect of 66 cases was evaluable, and the white blood count of 18 patients who did not reach complete remission was higher than that of 48 patients who reached complete remission ( Z = -2.74, P = 0.006). Conclusions:Most FLT3-ITD mutated patients with AML commonly show coexisting gene mutations, and the mutation types of coexisting genes are correlated with the clinical features of patients.

Proiferation inhibtion and pro-apoptotic effects of shikonin on human eukemia MV4-11 clls / 吉林大学学报(医学版)

Objective: To discuss the proliferation inhibition and apoptosis induction of shikonin on the FMS-like tyrosine kinase-3 receptor internal tandem duplication (FLT3-ITD) mutated acute myeloid leukemia (AMD MV4-11 cells, and to preliminarily clarify the molecular mechanisms. Methods: The MV4-11 cells were divided into DMSO group and different concentrations (0.5, 1.0, 2.0, 4.0, and 8.0 μmol · L-1) of shikonin groups, and treated for 24 and 48 h. The inhibitory rate of proliferation was analyzed by CCK-8 assay, and half inhibitory concentration (IC50) was calculated. The MV4-11 cells were divided into blank control group, DMSO group, and different concentrations (0.25, 0.50, and 1. 00 μmol · L-1) of shikonin groups, and treated for 48 and 72 h; the proliferation rate of cells was analyzed by carbox fluorescenceindiacetate succinimidyl este (CFSE). The MV4-11 cells were divided into DMSO group and different concentrations (0.702, 1. 404, and 2. 808 μmol · L-1) of shikonin groups, and treated for 48 h; the apoptotic rate was determined by flow cytometry. The MV4-11 cells were divided into DMSO group and different concentrations (0.351, 0.702, and 1. 404 μmol · L-1) of shikonin groups, and treated for 48 h; the microRNA-155 (miR-155) expression level was detected by Real-time PCR. Results: The results of CCK-8 and CFSE methods indicated that the inhibitory rates of proliferation of MV4-11 cells in different concentrations of shikonin groups were increased compared with DMSO grpup (P<0.05 or P<0.01), and the proliferation rates were decreased (P<0.05 or P<0.01) in a concentration-dependent manner; the IC50 of 24 and 48 h were 1. 743 and 1. 404 μmol · L-1, respectively. The flow cytometry results showed that the apoptotic rates of the cells in different concentrations of shikonin groups were increased compared with DMSO group (P<0.01) in a concentration-dependent manner. The Real-time PCR results showed that the expression levels of miR-155 in the cells in different concentrations of shikonin groups were decreased significantly (P<0.01), and the expression level in 1.404 μmol · L-1 shikonin group was decreased by more than 75%. Conclusion: Shikonin could inhibit the proliferation and promote the apoptosis of FLT3-ITD mutated AML MV4-11 cells, and down-regulate the expression of miR-155, suggesting that shikonin may be one of the potential therapeutic drugs for FLT3-ITD mututed AML.

Effect of FMS﹣like tyrosine kinase 3 mutations on prognosis of acute promyelocytic leukemia: a Meta﹣analysis / 白血病·淋巴瘤

Objective To systematically evaluate the effect of FMS﹣like tyrosine kinase 3 (FLT3) mutations on prognosis of acute promyelocytic leukemia. Methods The databases of CNKI, Wanfang, VIP, China Biology Medicine disc, PubMed, EMBase, and Cochrane Library were retrieved, and the cohort studies and case﹣control studies published from the establishment of the databases to December 2017 were selected according to the inclusion and exclusion criteria. The quality assessment and data extraction was performed and the statistical analysis was performed by using RevMan 5.3 software. Results Twenty﹣three studies were included, covering a total of 2 632 patients. Meta﹣analysis showed that patients with FLT3 internal tandem duplication (FLT3﹣ITD) mutation had lower complete remission rate ( RR＝0.92, 95% CI 0.86-0.99, P＝0.02), 3﹣year overall survival rate ( RR＝0.72, 95% CI 0.60-0.88, P＝0.001) and 5﹣year overall survival rate ( RR＝0.89, 95% CI 0.81-0.99, P＝ 0.03), while the proportion of high﹣risk group ( RR＝ 3.13, 95% CI 2.26-4.35, P< 0.01), the early mortality rate ( RR＝ 2.26, 95% CI 1.75-2.90, P< 0.01) and the recurrence rate ( RR＝1.50, 95% CI 1.11-2.02, P＝0.008) were relatively high, and the differences were statistically significant. The patients with FLT3 tyrosine kinase domain (FLT3﹣TKD) mutation had higher early mortality rate ( RR＝ 3.00, 95% CI 1.74-5.20, P< 0.01), and the difference was statistically significant. Conclusion The FLT3 mutations can influence the prognosis of acute promyelocytic leukemia, which contributes to the research direction of better prognosis stratification, perfect treatment regimen and improved prognosis.

FLT3 Mutations: Significance in Paediatric AML

Patients with acute myeloid leukaemia (AML) who have FMS-like tyrosine kinase 3 (FLT3) mutations are a concern for haematologists. Many studies indicate that these patients have poor prognosis. Due to the dearth of research in this area, the role of allogeneic transplantation as a therapy is still controversial. But the available limited data suggest that transplantation in first remission is possibly the first choice. As FTL3 mutations in AML result in poor patient outcomes, different FLT3 inhibitors are used as specific targeted therapy.

Midostaurin as a Novel Drug for the Therapy of FLT3 Mutation-positive Acute Myeloid Leukaemia / 中国药师

Midostaurin is an orally administered inhibitor of multiple tyrosine kinase receptors developed by Novartis Pharmaceuti-cals. In May 2017,it was approved in the USA for the treatment of adult patients with newly diagnosed FMS-like tyrosine kinase 3 (FLT3) mutation-positive acute myeloid leukaemia (AML). Its pharmacokinetics,pharmacodynamics,clinical trials,adverse effects and drug interactions were introduced in the paper.

Sorafenib combined with chemotherapy and donor lymphocyte infusion as salvage therapy in patients with FLT3-positive acute myeloid leukemia relapse after allogeneic hematopoietic stem cell transplantation / 中华内科杂志

To explore the efficacy of sorafenib combined with chemotherapy and donor lymphocyte infusion (DLI) in patients with FLT3-positive acute myeloid leukemia (AML) relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Of the 14 patients relapsed after allo-HSCT,9 achieved complete remission after salvage therapy of sorafenib combined with chemotherapy and DLI,6 with complete molecular remission,2 with partial remission,and 3 with no response.With a median follow up of 220 (range,30-1 782) days after post-transplantation relapse,7 patients were still alive and 7 died.Salvage therapy of sorafenib combined with chemotherapy and DLI shows a decent therapeutic effect for FLT3-positive AML relapsed after allo-HSCT.

Progress of FMS-like tyrosine kinase 3 internal tandem duplication-positive acute myeloid leukemia / 白血病·淋巴瘤

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutation is a commonly found type of mutation in acute myeloid leukemia (AML), and this mutation is closely related to the development of AML and affects the prognosis of patients. FLT3-ITD-positive AML patients have poor prognosis and high relapse rate after treated with chemotherapy alone. The efficacy of allogeneic hematopoietic stem cell transplantation for this disease is controversial. Targeted therapies such as sorafenib and the combination of different type of therapies have been carried out and have shown preliminary effect in preclinical or clinical trials. In this paper, the clinical effect of FLT3-ITD in AML patients and the latest progress of its treatment were reviewed.

AAcute WT1-positive promyelocytic leukemia with hypogranular variant morphology, bcr-3 isoform of PML-RARα and Flt3-ITD mutation: a rare case report / Leucemia promielocítica aguda WT1-positivo com morfologia variante hypogranular, isoforma bcr-3 da PML-RARα e mutação Flt3-ITD: relato de caso raro

ABSTRACT CONTEXT: Acute promyelocytic leukemia (APL) accounts for 8% to 10% of cases of acute myeloid leukemia (AML). Remission in cases of high-risk APL is still difficult to achieve, and relapses occur readily. CASE REPORT: Here, we describe a case of APL with high white blood cell counts in blood tests and hypogranular variant morphology in bone marrow, together with fms-like tyrosine kinase-3 with internal tandem duplication mutations (FLT3-ITD), and bcr-3 isoform of PML-RARα. Most importantly, we detected high level of Wilms’ tumor gene (WT1) in marrow blasts, through the reverse transcription polymerase chain reaction (RT-PCR). To date, no clear conclusions about an association between WT1 expression levels and APL have been reached. This patient successively received a combined treatment regimen consisting of hydroxycarbamide, arsenic trioxide and idarubicin plus cytarabine, which ultimately enabled complete remission. Unfortunately, he subsequently died of sudden massive hemoptysis because of pulmonary infection. CONCLUSION: Based on our findings and a review of the literature, abnormal functioning of WT1 may be a high-risk factor in cases of APL. Further studies aimed towards evaluating the impact of WT1 expression on the prognosis for APL patients are of interest.

RESUMO CONTEXTO: Leucemia promielocítica aguda (LPA) compreende 8% a 10% dos casos de leucemia mieloide aguda (LMA). A remissão em casos de LPA de alto risco ainda é dificilmente conseguida, e recorrência é comum. RELATO DE CASO: Descrevemos aqui um caso de LPA com glóbulos brancos elevados no exame de sangue e a morfologia variante hipogranular na medula óssea, juntamente com fms-like tirosina-quinase-3 com mutações de duplicação em tandem interna (FLT3-ITD) e a isoforma bcr-3 de PML- RARα. Mais importante, detectamos alto nível de gene do tumor de Wilms (WT1) em blastos medulares por RT-PCR (reverse transcription polimerase chain reaction). Até agora, não há conclusões claras sobre a associação entre os níveis de expressão WT1 e APL. Este paciente recebeu sucessivamente regime de tratamento combinado, de hidroxicarbamida, trióxido de arsênico e idarrubicina e citarabina, alcançando finalmente a remissão completa. Infelizmente, em seguida, ele morreu de repente de hemoptise maciça devido a uma infecção pulmonar. CONCLUSÃO: Com base em nossos resultados e numa revisão da literatura, a função anormal de WT1 pode ser um fator de alto risco em casos de APL. Novos estudos, com o objetivo de avaliar o impacto da expressão de WT1 no prognóstico dos doentes com APL, são de interesse.

Prognostic value of FLT3-ITD detection on acute myelogenous leukemia by DNA extracted from stored bone marrow slides by chemical method / 白血病·淋巴瘤

Objective To investigate the prognostic value of Fms-like tyrosine kinase3, intenal tandem duplication (FLT3-ITD) detection by DNA extracted from stored bone marrow slides in chemical method. Methods Trace DNA was extracted from 58 bone marrow slides which were stored for 1-5 years below 20 ℃, including 48 patients with de novo acute myeloid leukemia (AML) and 10 controls without hematologic malignancies. Polymerase chain reaction (PCR) was used to detect the FLT3-ITD of these bone marrow slides samples. Results There were 6 patients of FLT3-ITD+ detected in these 48 AML patients (12.5 %, 6/48). No FLT3-ITD was found in 10 healthy controls. AML patients with FLT3-ITD+ had low complete time compared with FLT3-ITD-patients (x2= 7.274, P= 0.007). Splenohepatomegalia and FLT3 mutation were the risk factors affecting AML patients with CR after the first chemotherapy (OR= 7.2, P=0.12; OR=36.3, P=0.10). FLT3-ITD was a risk factor of poor prognosis in patients with newly diagnosed AML (RR=9.088, P= 0.029). Conclusion Extraction of AML bone marrow slides trace DNA by using chemical method can be widely applied in clinic and is a key experimental way to study the molecular biology retrospectively. Furthermore, the detection of FLT3-ITD by trace DNA extracted from stored bone marrow slides can be used to predict the prognosis of AML.

Effects of triptolide on proliferation and apoptosis of acute myeloid leukemia cell line MV411 with FMS-like tyrosine kinase 3 internal tandem duplication and their mechanisms / 白血病·淋巴瘤

Objective To investigate the effects of triptolide (TP) on proliferation and apoptosis of acute myeloid leukemia cell line MV411 with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD), and its effect on PI3K-Akt-mTOR pathway. Methods MTT assay was used to detect the proliferation inhibition of MV411 cell proliferation treated by different concentrations of TP in 24, 48 and 72 h. Flow cytometry was used to measure the cell apoptosis rate at 48 and 72 h. Real-time fluorescent quantitative PCR was used to detect the expression of FLT3, PTEN, PI3K, Akt, mTOR mRNA on PI3K-Akt-mTOR pathway. Results After treated by 0, 5, 10, 20, 40, and 80 nmol/L TP in 24, 48 and 72 h, the viability of MV411 cells was inhibited in a time-dose dependence manner. MV411 cells was treated by 0, 10, and 20 nmol/L TP after 48 and 72 h, the cell apoptosis rates were rising with the increasing of drug concentration, there were statistical significances [48 h:(3.30±0.20) %, (17.10±0.36) %, (35.67±0.61) %, 72 h: (7.37±0.32) %, (49.33± 0.40)%, (68.92±0.11)%, all P=0.000]. The expressions of FLT3, PI3K, Akt, and mTOR mRNA were down-regulated and PTEN mRNA expression was up-regulated by TP. Conclusion TP may inhibit the proliferation and induce apoptosis of MV411 cells by affecting the expression of PI3K-Akt-mTOR pathway related genes.

Clinical feature between FLT3-ITD mutation type and wild type de novo primary AML / 实用医学杂志

Objective To investigate the difference of clinical features between FLT3-ITDmt and FLT3-IT-Dwt de novo primary acute myeloid leukemia(AML). Methods Clinical data of 31 FLT3-ITDmt and 113 FLT3-ITDwt de novo primary AML patients from January 2015 to December 2016 were retrospectively reviewed and ana-lyzed by Student′s test,chi-square test or rank sum test according to the types of clinical data. Results There were statistically significant differences in WBC,RBC,HGB of peripheral blood and the mutation of DNMT3A gene(statistical values:705.000;-2.535;-2.290 and 5.715 respectively,all P < 0.05)in 2 types of AML. Conclusion When compared with FLT3-ITDwt de novo primary AML patients,FLT3-ITDmt ones have the fea-tures of higher WBC,lower RBC and HGB of peripheral blood,and are more likely to be associated with mutation in the DNMT3A gene.

Detection of FMS-like tyrosine kinase 3 internal tandem duplication in acute myeloid leukemia patients and its clinical significance / 白血病·淋巴瘤

Objective To analyze the mutations of FMS-like tyrosine kinase 3 internal tandem duplication (FLT3/ITD) in bone marrow cells of patients with newly-diagnosed acute myeloid leukemia (AML).Methods The mutations of FLT3/ITD in 96 AML cases were detected by polymerase chain reaction (PCR)and the clinical features of FLT3/ITD positive patients were analyzed.Results FLT3/ITD mutations were identified in 18 patients (18.8 ％),2 cases were M2,11 cases were M3,2 cases were M4,3 cases were Ms.Patients with FLT3/ITD mutations presented higher initial white blood cell count than that of patients without FLT3/ITD mutations [18.0×109/L (3.6×109-137.6×109/L) vs 6.3×109/L (4.5×109-113.0×109/L),t =3.04,P ＜ 0.05].Out of FLT3/ITD positive patients,13/16 (81.3 ％) obtained complete remission and 13 patients remained in first remission in a median follow-up of 10 months(6-15 months).Conclusion The mutations of FLT3/ITD are frequently identified in newly-diagnosed AML patients,patients with FLT3/ITD mutations present high white blood cell count.

Serial Determination of FLT3-ITD and NPM1 Mutations and Its Clinical Significance in Patients with MDS at Diagnosis and After Progression to AML with Myelodysplasia-related Changes

BACKGROUND: Accumulation of genetic aberrations in MDS is closely associated with progression to AML. FLT3-ITD is commonly found in AML and less frequently in MDS. FLT3-ITD in MDS is associated with a high risk of transformation to AML. Recently, significant interaction of NPM1 and FLT3-ITD was described in AML. This study was conducted to investigate the incidence and prognostic role of FLT3-ITD and NPM1 mutations (NPM1mt) on paired samples at diagnosis of MDS and AML. METHODS: Patients who were diagnosed as MDS transforming to AML were included. FLT3-ITD was detected by PCR, and NPM1mt was confirmed by direct sequencing after screening for NPM by immunohistochemistry. RESULTS: AML developed in 12.0% (43/357) of MDS patients. FLT3-ITD was detected in none of MDS and 14.7% (5/34) of AML. NPM1mt was detected in 2.4% (1/41) of MDS and 11.6% (5/43) of AML. One patient with type B NPM1mt at MDS transformed to type A NPM1mt at AML. FLT3-ITD positive AML showed a tendency of shorter survival and a significantly longer time to achieve complete remission than FLT3-ITD negative AML (P=0.007). Normal karyotype AML with FLT3-ITD showed shorter overall survival than that group of AML without FLT3-ITD (P=0.017). CONCLUSIONS: MDS patients acquired FLT3-ITD during AML transformation, and FLT3-ITD positive AML, especially that with normal karyotype, predicted a poor outcome. NPM1mt was identified in both MDS and AML. NPM1mt was rarely found in MDS patients, and mostly was acquired after AML transformation. Clonal evolution of NPM1mt subtype was found in one patient during acute transformation.

Prevalence and clinical significance of FLT3 internal tandem duplication mutation in acute myeloid leukemia of older people / 白血病·淋巴瘤

Objective The aim of the study was to detect the mutation of Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-1TD) rate in older de novo acute myeloid leukemia (AML) patients, to evaluate the role of FLT3-ITD in AML and its clinical significance. Methods The mutations of FLT3-1TD in bone marrow mononuelear cells (MNCS) from 30 cases of older AML were screened by polymerase chain reaction denaturing-high performance liquid chromatography (PCR-DHPLC). Results FLT3-1TD mutations were identified in 26.67 %(8/30) patients, while there were no mutations identified in control cases. And these kinds of mutations were likely to attend in M3 types. All mutations of FLT3-ITD were heterozygous and rearrangement fragment located in reading frame. Different karyomite groups had different FLT3-ITDmutations rate. We could see that FLT3-ITD positive patients were more prevalent in patients with normal karyotype. Clinical researches indicated that FLT3-ITD mutations had the characteristics of a higher peripheral white cell count, higher blast cells and lower complete remission rate in older AMKA Conclusion FLT3-ITD positive older AML patients conferred a poor prognosis and were likely to attend in normal karyomite group. The detection of FLT3-ITD mutations could make up for the deficiency of cytogenetics to some extent, and may become a routine examination of AML in older, which can direct their treatment and predict their prognosis.