Incidence and clinical significance of FLT3 and nucleophosmin mutation in childhood acute myeloid leukemia in Chile

Abstract Introduction Acute myeloid leukemia (AML) is a heterogeneous disease and approximately one-third of its carriers do not have evident genetic abnormalities. The mutation of specific molecular markers, such as fms-like tyrosine kinase 3 (FTL3) internal tandem duplication (ITD), FLT3 tyrosine kinase domain (TKD) and nucleophosmin (NPM1), are associated with an adverse and favorable prognosis, respectively. Objective The objective was to determine the prevalence of FLT3/ITD and NPM1 in Chilean patients and their association with clinical data and prognosis. Method and Results Two hundred and thirty-two children were studied between 2011 and 2017, the median being 8.6 years (ranging from 1 to 18 months). Acute promyelocytic leukemia (APL) was diagnosed in 29%. The FLT3/ITD-mutated in non-promyelocytic AML was at 10% (14/133) and the FLT3/TKD, at 3.7% (2/54). In APL, it was at 25.4% (16/63). In non-promyelocytic AML, the FLT3/ITD-mutated was associated with a high leucocyte count, the median being 28.5 x mm3 (n= 14) versus 19.4 x mm3 (n= 119), (p= 0.25), in non-mutated cases. In APL, the median was 33.6 x mm3 (n= 15) versus 2.8 x mm3 (n= 47), (p < 0.001). The five-year overall survival (OS) in non-promyelocytic AML with non-mutated and mutated FLT3/ITD were 62.7% and 21.4%, respectively, (p < 0.001); the 5-year event-free survival (EFS) were 79.5% and 50%, respectively, (p < 0.01). The five-year OS in APL with non-mutated and mutated FLT3/ITD was 84.7% and 62.5%, respectively, (p= 0.05); the 5-year EFS was 84.7% and 68.8%, respectively, (p= 0.122). The NPM1 mutation was observed in 3.2% (5/155), all non-promyelocytic AML with the normal karyotype. Conclusion The FLT3/ITD mutation was observed more frequently in APL and associated with a higher white cell count at diagnosis. However, the most important finding was that the FLT3/ITD mutation was associated with a shorter survival in non-promyelocytic AML.

Analysis of laboratory characteristics and evaluation of prognostic value of patients with NPM1 mutated acute myeloid leukemia / 中华检验医学杂志

Objective:To analyze the clinical and laboratory characteristics of acute myeloid leukemia (AML) patients with NPM1 mutation, and to explore the prognostic factors.Methods:A total of 77 AML patients with NPM1 gene mutation admitted to Hebei Yanda Ludaopei Hospital from May 1st 2012 to December 31st 2021 were enrolled in the study, including 34 male and 43 female patients. The median age was 40 (3, 68) years old. Patients were selected and divided into 4 groups according to the morphological FAB classification. There were 29 cases (37.7%) of M1 type, 13 cases (16.9%) of M2 type, 23 cases (29.9%) of M4 type, and 12 cases (15.5%) of M5 type. The clinical characteristics, bone marrow/peripheral blood cell morphology, immunophenotype, cytogenetics, molecular biology and overall survival of different groups were retrospectively analyzed, and the risk factors affecting the prognosis of AML were also explored. Cox multivariate regression was used to analyze the clinical influencing factors of survival and prognosis.Results:The white blood cell counts were highest in M4 and M5 patients and lowest in M2 patients, while no significant difference in the red blood cell, hemoglobin, and platelet counts( P>0.05). Morphologically, there were significant differences in the percentage of blasts and blasts with cup-like nuclei on bone marrow (BM) and peripheral blood (PB). The proportion of blasts in BM and PB was the highest in M1 and the lowest in M2 ( P<0.001). The positive rate of blasts with cup-like nuclei was the highest in M1 and the lowest in M5 of BM ( P<0.001), while the highest in M2 and the lowest in M5 of PB ( P=0.006). The scores of myeloperoxidase and chloroacetate esterase were all the highest in M1 and the lowest in M5 ( P<0.001, 0.001, respectively). In terms of molecular biology, the occurence rate of blasts combined with DNMT3A mutation was the highest in M4 and the lowest in M2 ( P=0.044), while those combined with FLT3-ITD mutation was the highest in M4 and the lowest in M5 ( P=0.002). In immunophenotype, there were significant differences in the expression positivities of seven antigens including HLA-DR, CD56, CD11c, CD15, CD14, CD96 and cMPO ( P<0.05). Multivariate COX regression analysis showed that no recurrence after treatment ( P<0.001), complete remission after treatment ( P=0.015) and transplantation ( P<0.001) were correlated with overall survival (OS). No recurrence after treatment ( P=0.033), transplantation ( P=0.027), no mutation of FLT3-ITD ( P=0.040), and hemoglobin concentration ( P=0.023) were associated with relapse-free survival (RFS). Survival analysis by Kaplan-Meier curve showed that there was no significant difference in survival time between the M1, M2, M4 and M5 groups in OS and RFS. Conclusion:There were significant differences in the white blood count, the percentage of blasts and blasts with cup-like nuclear morphology, cytochemical staining (MPO integration, CE integration and percentage of NAS-DCE), gene mutation (DNMT3A and FLT3-ITD) and immunophenotypes (HLA-DR, CD56, CD11c, CD15, CD14, CD96 and cMPO) between the four groups. The multivariate analysis revealed that no recurrence after treatment and transplantation were independent prognostic factors in NPM1 mut AML patients. On the other hand, FLT3-ITD mutation and hemoglobin concentration were associated with RFS and complete remission after treatment was associated with OS in the entire NPM1 mut cohort.

Biomarcador FLT3-ITD: perspectivas y retos / FLT3-ITD biomarker: perspectives and challenges

Introducción: Las mutaciones del gen que codifica para el factor de la tirosina quinasa 3 (FLT3) son de especial importancia en la leucemia mieloide aguda debido a que sirven de guía para la confirmación del diagnóstico, la estimación del pronóstico y la toma de decisiones terapéuticas. Entre las alteraciones más importantes está la duplicación interna en tándem (FLT3-ITD). Objetivo: Exponer los aspectos más relevantes respecto al biomarcador FLT3-ITD en el contexto de la leucemia mieloide aguda. Métodos: Se realizó una búsqueda de artículos científicos actualizados en los idiomas inglés y español, en PubMed, EMBASE, Google Scholar y SciELO. Se seleccionaron artículos publicados en los últimos cinco años. Se revisaron los aspectos más relevantes sobre el biomarcador en el contexto de la leucemia mieloide aguda, su base biológica, el impacto del tamaño de los fragmentos y la carga alélica en la estimación del pronóstico de los pacientes, las nuevas estrategias terapéuticas y los retos en cuanto a los métodos de laboratorio para su diagnóstico. Análisis y síntesis de la información: Más allá de la positividad o no de dicho biomarcador, el tamaño de la duplicación interna en tándem, así como la carga alélica -determinada por la razón alelo mutado/alelo salvaje-, podrían tener un gran impacto en el pronóstico. Sin embargo, persisten diferencias en los criterios para establecer los algoritmos de predicción del riesgo, el punto de corte a utilizar como referencia y el protocolo de laboratorio específico para un estudio más detallado del biomarcador. Conclusiones: La comunidad científica necesita seguir trabajando en el esclarecimiento de la utilidad práctica de estos parámetros, validándolos en series amplias y diversas epidemiológicamente. Se debe determinar el punto de corte exacto para comparar la razón y estandarizar los métodos de laboratorio más adecuados y factibles para su estudio(AU)

ABSTRACT Introduction: Mutations in the tyrosine kinase 3 gene (FLT3) are of special importance in acute myeloid leukemia because they serve as a guide to confirm the diagnosis, estimate the prognosis, and make therapeutic decisions in the patient. Internal tandem duplication (FLT3-ITD) is the most important alteration of this gene. Objective: To present the most relevant aspects regarding the FLT3-ITD biomarker in the context of acute myeloid leukemia. Methods: a search was carried out for updated scientific articles, in English and Spanish, in PubMed, EMBASE, Google Scholar and SciELO. Articles published in the last five years were selected. The most relevant aspects of the biomarker in the context of acute myeloid leukemia, its biological basis, the impact of the size of the fragments and the allelic load in the estimation of the prognosis of the patients, the new therapeutic strategies and the challenges in regarding the laboratory methods for its diagnosis. Information analysis and synthesis: Beyond the biomarker positivity or not, the size of the ITD, as well as the allelic ratio determined by the mutated allele / wild-type allele, could have a great impact on the prognosis of patients. However, differences persist in the criteria for establishing risk prediction algorithms, the cut-off point to be used as a reference, and the specific laboratory protocol for a more detailed study of the biomarker. Conclusions: The scientific community needs to continue working to clarify the practical utility of these parameters, validating them in broad and epidemiologically diverse series. The exact cut-off point should be determined as a reference to compare the relationship and standardize the most suitable and feasible laboratory methods for its study(AU)

Effect of MiR-155 Knockout Mediated by Dual sgRNAs on Drug Sensitivity of FLT3-ITD+AML / 中国实验血液学杂志

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.

Association of Next Generation Sequencing Based Genotypic Profiling with MICM Characteristics in NPM1 Mutated Acute Myeloid Leukemia / 中国实验血液学杂志

OBJECTIVE@#To explain the clinicobiological heterogeneity of NPM1 mutated (NPM1mut) 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 NPM1mut 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 NPM1mut 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 NPM1mut/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. NPM1mut occurred solely as an insertion/deletion (indel) type in the NPM1mut/FLT3-ITD+ group. The incidence of favorable plus unfavorable karyotypes in NPM1mut/FLT3-ITD- group was higher than in NPM1mut/FLT3-ITD+ group (6.4% vs. 0, P=0.031). The positive rates of CD34 and CD7 in NPM1mut/FLT3-ITD+ group were significantly higher than in NPM1mut/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 NPM1mut 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.

Clinical Correlation of Lactate Dehydrogenase Activity with JAK2V617F and FLT3 Mutations in Myeloproliferative Disorders and Acute Myeloid Leukemia: Indian Population

Background: Lactate dehydrogenase (LDH) play main role in the cell damage.Previous study has shown elevated level in acute leukemia and myeloproliferative disorders. Molecular markers specifically for JAK2V617F mutation in myeloproliferative disorders (MPDs) and FLT3 mutations in acute myeloid leukemia patients (AML) are well known for clinical practice. But, still only few reports have shown the correlation of LDH activity with molecular markers in Hematological Malignancy. Therefore, aim of study is to correlate LDH activity with established specific molecular markers in MPDs and AML. Methods:10 healthy individuals, 50 patients with MPDs and 50 patients with AML were included for the study. Serum LDH was performed by autoanalyser. The JAK2V617F mutations is analyse from blood by Real time PCR and FLT3 ITD/D835 mutations are analysed from blood by PCR-RFLP respectively. Statistical analysis was done by SPSS statistical software. Results: LDH Activity were higher in MPDs and AML as compared with healthy individual. Mean LDH activity was higher in FLT3 ITD/D835 positive mutation and JAK2V617F positive mutation in AML and MPDs respectively was observed. Conclusion: High LDH activity with Positive frequency of FLT3 ITD/D835 mutation in Acute Myeloid Leukemia and Positive frequency of JAK2V617F mutation in Myeloproliferative Disorders were observed.

Favorable long-term survival using consolidation chemotherapy without allogeneic hematopoietic cell transplantation for acute myeloid leukemia with wild-type NPM1 without FLT3-ITD

BACKGROUND: The role of allogeneic hematopoietic cell transplantation (allo-HCT) compared with consolidation chemotherapy alone in intermediate-risk acute myeloid leukemia (AML) patients with wild-type nucleophosmin/negative or a low level of Fms related tyrosine kinase 3 internal tandem duplication (NPM1(wt)/FLT3-ITD(neg/low)) has not yet been elucidated. METHODS: In this study, we retrospectively investigated 88 patients newly diagnosed with AML who received intensive induction chemotherapy at Kyungpook National University Hospital from March 2015 to July 2017. The selection criteria included the presence of results on genetic abnormalities including NPM1 and FLT3-ITD. RESULTS: According to the European LeukemiaNet (ELN) risk classification, 25 patients (28%) were categorized as favorable, 44 (50%) as intermediate, and 19 (22%) as adverse risk. Among the intermediate-risk patients, 40 were identified as NPM1 wt/FLT3-ITDneg/low. Among the patients with NPM1(wt)/FLT3-ITD(neg/low), complete remission (CR) was achieved in 26 patients out of 40 (65%). One-year overall survival (OS) rate was 100% in the favorable-risk group and 87.9% in the NPM1(wt)/FLT3-ITD(neg/low) group (P=0.233). Among the intermediate-risk NPM1(wt)/FLT3-ITD(neg/low) patients, there was no survival benefit with allo-HCT (N=19) compared to consolidation chemotherapy (N=21; P=0.372). In the multivariate analysis, the ELN risk group [hazard ratio (HR), 6.36; P=0.019] and the achievement of CR (HR, 2.95; P=0.017) were both identified as factors affecting OS of patients with newly diagnosed AML. CONCLUSION: Among the AML patients, intermediate-risk NPM1(wt)/FLT3-ITD(neg/low) patients and favorable-risk patients showed similar OS rates. Our results suggested that allo-HCT might have limited clinical benefit for the intermediate-risk NPM1(wt)/FLT3-ITD(neg/low) patients. Well controlled studies are needed to confirm the current results.

Analysis of induction efficacy and prognostic factors in FLT3-ITD positive acute myeloid leukemia in the real world / 中华血液学杂志

Objective@#To investigate the efficacy and prognostic factors of induction therapy in FLT3-ITD+ acute myeloid leukemia (AML) in the real world data.@*Methods@#From January 2013 to December 2016, 114 de novo patients with FLT3-ITD+AML were enrolled in this study. Out of 114 cases, 75 were male, and 39 were female. The median age was 42 years old (ranged from 14 to 72 years old) . The chemotherapy regimens were used for induction therapy and all cases were followed up. The treatment response was evaluated by MICM and the comparison of the ratio were analyzed by chi-square test and the survival was estimated by Kaplan-Meier analysis and Cox proportional hazards model was used to identify independent prognostic factors.@*Results@#There were 52 FLT3-ITD+AML patients with favorable prognosis genes (46 cases with NPM1, 5 cases with RUNX1-RUNX1T1, 1 case with CEBPA double mutation) and 62 patients with other types of FLT3-ITD+AML at diagnosis. All patients completed at least one cycle of induction therapy and the clinical curative effect was evaluated, complete remission (CR) rate was 50.0% (57/114) in one cycle and total CR rate was 72.5% (74/104) in two cycles. The CR rate of the FLT3-ITD+ AML patients with favorable prognosis genes was 67.3% (35/52) in one cycle and 83.3% (40/48) in two cycles; for the other types FLT3-ITD+AML patients, the CR rate was 35.5% (22/62) in one cycle and 64.8% (35/54) in two cycles. There was a significant difference in CR rate between the FLT3-ITD+AML patients with and without favorable prognosis genes (P<0.05) . This indicates that the FLT3-ITD+AML patients with favorable prognosis gene had relatively good therapeutic effect. Among other types of FLT3-ITD+AML patients who did not achieve remission from one cycle of chemotherapy, 9 patients were given sorafenib plus chemotherapy and 6 cases (66.7%) achieved CR; 23 patients were given conventional chemotherapy and 7 cases (30.4%) achieved CR. There was a significant difference between sorafenib plus chemotherapy and conventional chemotherapy groups (χ2=4.47, P<0.05) and this indicates that sorafenib plus chemotherapy can significantly improve the CR rate of FLT3-ITD+AML patients. Comparing overall survival (OS) and disease free survival (DFS) , there was no significant difference between sorafenib plus chemotherapy and conventional chemotherapy groups (P values were 0.641 and 0.517, respectively) .@*Conclusion@#The overall prognosis of FLT3-ITD+AML patients is poor, and the stratification therapeutic efficacy of FLT3-ITD+AML without favorable prognosis gene can be improved by sorafenib combined with chemotherapy.

The clinical observation of relapsed or refractory acute myeloid leukemia in patients with high CD117 expression but no FLT3-ITD mutation treated with sorafenib alone / 天津医药

@#Objective To make a primary investigation of outcomes in relapsed or refractory (R/R) acute myeloid leukemia (AML) patients who were FLT3-ITD mutation negative and treated with sorafinib alone. Methods The clinical responses and survival of R/R AML patients who underwent sorafenib treatment only were retrospectively analyzed. The side effects and response results were assessed according to common terminology criteria for adverse events (CTCAE) v 4.0 from US National Institutes of Health and NCCN guideline. Results Four out of seven patients achieved complete remission by sorafenib treatment alone. The median time required for remission was 36 days in the four patients. Among them, only 1 patient stopped the maintenance treatment because of side effect of serious skin lesion. Three patients showed no response to sorafenib, including 2 accepted stem cell transplantation and 1 retrieved to salvage chemotherapy. All of them achieved complete remission later. One patient developed grade 1 adverse event of liver. Another one developed grade 3 skin lesion. All patients experienced neutropenia of more than 7 days without unendurable infections and early deaths. The median follow-up time for the whole cohort was more than 22 months. Three patients passed away for relapse of AML and their disease-free survival time with sorafenib ranged from 2 to 20 months. All four patients accepted stem cell transplantation were still surviving no matter whether or not they were responsive to sorafinib before. The median survival time for these seven patients was 650 days. Conclusion The R/R AML patients with negative FLT3-ITD mutation and high expression of CD117 treated with sorafenib alone have good remission and long term survival.

Effect of FLT3-ITD with DNMT3A R882 double-mutation on the prognosis of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation / 中华血液学杂志

Objective@#To investigate the impact of FLT3-ITD and DNMT3A R882 double mutations to the prognosis of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT).@*Methods@#FLT3-ITD, DNMT3A, C-kit, CEBPA, FLT3-TKD and NPM1 mutations were detected in 206 newly diagnosed AML patients by Sanger sequencing (M3 and those received FLT3 inhibitor were excluded). Clinical data of AML patients were retrospectively analyzed to compare the prognosis of each gene mutation group.@*Results@#①Of 206 patients, 104 were male and 102 female with a median age of 38 (3-63) years, including 6 cases of M0, 24 cases of M1, 56 cases of M2, 39 cases of M4, 63 cases of M5, 6 cases of M6 and 12 unclassified cases. ②All 206 patients were divided into four groups according to the mutation gene at the time of diagnosis: FLT3-ITD+ DNMT3A R882+ group (group A), FLT3-ITD+ DNMT3A R882- group (group B), FLT3-ITD- DNMT3A R882+ group (group C) and FLT3-ITD- DNMT3A R882- groups (group D). Gender, leukocyte count at diagnosis, chromosome karyotype, the median age, FAB classification, disease status prior to transplantation, type of donor, conditioning regimen and GVHD were not significantly different between four groups (P>0.05). ③The 2-year cumulative recurrence rate (CIR) of group A was significantly higher than that of other groups [group A (72.2±2.6)%, group B (38.6±0.6)%, group C (36.8±1.6)%, group D (27.8±0.1)%, respectively, P<0.05], while the 2-year overall survival (OS) rate and 2-year leukocyte-free survival (LFS) rate were lower than those of other groups [group A (30.9±13.3)%, (11.3±10.2)%; group B (67.5±7.8)%, (47.9±8.4)%; group C (61.4±12.4)%, (56.8±12.5)%; group D (80.1±3.7)%, (79.7±3.6)%, respectively, P<0.05].@*Conclusion@#AML patients with FLT3-ITD and DNMT3A R882 double mutations had a very high CIR and low OS, LFS after transplantation.

Mutation analysis of FLT3-ITD gene in acute myeloid leukemia / 中国病理生理杂志

AIM:To investigate the mutation of FLT3-ITD gene in the patients with newly diagnosed acute myeloid leukemia (AML). METHODS:From March 1, 2015 to June 1, 2017, 207 patients with AML admitted to de-partment of hematology, sichuan provincial people′s hospital were enrolled in this study. The bone marrow samples were collected from the patients. PCR was used to detect the mutation of FLT3-ITD gene. After the corresponding chromosome was obtained by R-banding, the cells were made into strips and banding. Twenty karyotypes with relatively cleavage were automatically selected from each specimen to complete karyotyping. By analysis of the clinical data and following-up the prognosis, the FLT3-ITD gene mutation in diagnostic and evaluative values for AML were performed. RESULTS:FLT3-ITD gene mutation was found in 42 cases of 207 AML patients, the positive rate was 20. 29 % . FLT3-ITD positive patients showed 3 bands. FLT3-ITD gene mutation in 42 patients with positive results showed that FLT3-ITD gene mutations in turn met the end to end, and insert a number of nucleotides, but all the mutations were in-frame mutations. According to the FAB and WHO standard, in 42 cases of FLT3-ITD positive positive patients, M0 accounted for 0.00% , M1 accounted for 2.38% (1/42), M2 accounted for 23.81% (10/42), M3 accounted for 0.00% , M4 accounted for 2.38% (1/42), M5 accounted for 69.05% (29/42), M6 accounted for 0.00% , M7 accounted for 2.38% (1/42). The white blood cell ( WBC) level and complete response (CR) rate in FLT3-ITD positive patients were lower than those in FLT3-ITD negative patients (P<0.05). CONCLUSION:The WBC level and CR rate, which are lower in FLT3-ITD positive patients than those in negative patients, are the clinical risk factors. It will be helpful to determine the prognosis evaluation for AML pa-tients.

The analysis of prognosis-associated factors in adults with acute promyelocytic leukemia / 中华血液学杂志

Objective@#To explore the prognostic value of CD34, CD2, CD56 expressions and FLT3-ITD mutation in adults with acute promyelocytic leukemia (APL) .@*Methods@#The immuno-phenotypic and molecular characteristics of 137 adult patients with APL (from January 2010 to March 2016, in Henan Provincial People’s Hospital) were investigated. And the relationships between CD34, CD2, CD56 expressions, FLT3-ITD mutation and the outcomes of high WBC counts at onset, complete remission (CR) rate, early mortality, relapse rate (RR) , overall survival (OS) , disease free survival (DFS) were explored.@*Results@#①Among the 137 patients, the positive ratios of CD34, CD2, CD56 expressions and mutation rate of FLT3-ITD were 26.3%, 25.5%, 10.2% and 17.5%, respectively. The morbidities of positive CD34, CD2, CD56 expressions and FLT3-ITD mutation in the high-risk group were 43.2%, 47.7%, 18.2% and 27.3% respectively, while those in the low-/intermediate-risk groups were 18.3%, 15.1%, 6.5% and 12.9%, respectively (P<0.05) . ②At a median follow-up of 41 months, the total CR rate of the 137 adults APL patients was 96.9%, early mortality 6.6% and relapse rate 7.3% respectively. And RR of positive CD34 or CD2 expression patients was higher than negative CD34/CD2 expression ones (18.8% vs 3.3%, χ2=8.462, P=0.004; 16.1% vs 4.3%, χ2=4.382, P=0.028, respectively) . In addition, the early mortality of patients with positive CD56 expression or FLT3-ITD mutation was extremely higher than in negative ones (21.4% vs 4.9%, χ2=5.610, P=0.018; 16.7% vs 4.4%, χ2=4.833, P=0.028, respectively) . ③The whole OS and DFS were 88.3% and 84.7%, respectively. Wherein, OS and DFS in patients with CD34+, CD56+ or FLT3-ITD mutation were worse (P<0.05) .@*Conclusions@#Positive CD34, CD2, CD56 expression and FLT3-ITD mutation were latent poor prognostic factors in adults with APL.

Sorafenib in combination with chemotherapy as first-line therapy for FLT3-ITD positive acute myeloid leukemia / 中华血液学杂志

Objective@#To analyze the clinical features of acute myeloid leukemia patients with Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutation and the therapeutic effect of sorafenib in combination with chemotherapy as first-line therapy for these patients.@*Methods@#Clinical features and therapeutic effect were retrospectively analyzed in 53 AML patients with FLT3-ITD mutation diagnosed in Henan Cancer Hospital from January 2013 to August 2016. The biological characteristics and clinical efficacy of chemotherapy in combination with or without Sorafeinb were analyzed.@*Results@#FLT3-ITD mutation was identified in 53 AML patients, 22 cases (41.5%) were M5 subtype. The median of the peripheral WBC was 61.00 (0.98-920.00) ×109/L, and there were 50 (94.3%) patients with WBC>10×109/L. The median of blast cell in bone marrow was 0.730 (0.234-0.966) . The total remission rate of all these 53 patients was 56.6% (30/53) . The complete remission (CR) rates in patients treated with chemotherapy in combination with sorafenib and patients with chemotherapy alone were 86.4% (19/22) and 35.5% (11/31) , respectively. The 1-year overall survival rates of the two groups were 78.3%% and 50.0% (P=0.041) , and 1-year progression free survival rates were 75.9% and 42.4% (P=0.044) , respectively.@*Conclusion@#AML patients with FLT3-ITD mutation have the characteristics of high peripheral WBC, high blast cells in bone marrow and accompanying with M5 subtype. Sorafeinb combined with chemotherapy can significantly improve CR rate and short term survival.

Construction and identification of FLT3-ITD/FIV expression vector and acute myelogenous leukemia cell lines / 中国药科大学学报

The aim of this study was to construct the lentivirus expression vector of human FLT3-ITD mutation and to screen the AML cells for stable expression of FLT3-ITD.We screened the AML patient with FLT3-ITD mutation by peripheral blood DNA extraction and PCR,and then the ORF of FLT3-ITD was constructed using the method of homologous recombination,which used the BamH Ⅰ and Not Ⅰ double enzyme digestion of the ORF and the FIV vector.Results were confirmed by restriction enzyme identification and PCR.The constructed recombinant vector was co-transfected with VSVG and g/p into HEK293T cells to produce the lentiviral parti cles by transfection reagent.The lentiviral particles were transduced into K562 cells and the infection efficiency was measured by fluorescence microscope.The cells were sorted by the Flow Cytometer.The expression of FLT3 in the stable cell lines was detected by Western blot.There were 42 patients with FLT3-ITD mutation among the 207 patients we collected.We successfully amplified the ORF of FLT3 of the patient with highest mutant/wt ration.Then constructed the lentivirus expression vector FLT3-ITD/FIV and overexpressed it in K562 cell lines.We screened the cells expressed FLT3-ITD/FIV by fluorescence activated cell sorting,and Western Blot results proved the expression of FLT3-ITD.The over-expression 1 entiviral vector of human FLT3-ITD/FIV has been successfully constructed and cell lines for stable expression of FLT3-ITD have been successfully established.This will shed a light on the future study of FLT3 function in AML and provide a new in vitro model for AML.

Analysis of the presence of FLT3 gene mutation and association with prognostic factors in adult and pediatric acute leukemia patients

ABSTRACT When the FLT3 gene is mutated, it originates a modified receptor with structural changes, which give survival advantage and malignant hematopoietic cell proliferation. Thus, the presence of mutations in this gene is considered an unfavorable prognostic factor. A total of 85 consecutive samples of newly diagnosed untreated patients with AL were included in the study after they provided their informed consent. FLT3 gene mutations were detected by PCR. For the pediatric group, a positive correlation was observed between WBC count and the presence of FLT3-ITD in patients with AML and ALL. Furthermore, children with AML who had the FLT3-ITD mutation showed a tendency to express CD34 in blast cells. In the adult group, the AML patients with FLT3-ITD who expressed CD34 in blast cells had a tendency to worse progression. The present data indicate no association between the prognostic factors evaluated and FLT3 gene mutations in adult with AL. Yet, the presence of FLT3-ITD mutation was significantly related with WBC count in the pediatric group. These findings demonstrate that FLT3 gene mutations can be considered as independent poor prognostic factors.

Fragment Analysis for Detection of the FLT3-Internal Tandem Duplication: Comparison with Conventional PCR and Sanger Sequencing

BACKGROUND: We evaluated a sensitive and quantitative method utilizing fragment analysis of the fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD), simultaneously measuring mutant allele burden and length, and verified the analytical performance. METHODS: The number and allelic burden of FLT3-ITD mutations was determined by fragment analysis. Serial mixtures of mutant and wild-type plasmid DNA were used to calculate the limit of detection of fragment analysis, conventional PCR, and Sanger sequencing. Specificity was evaluated using DNA samples derived from 50 normal donors. Results of fragment analysis were compared to those of conventional PCR, using 481 AML specimens. RESULTS: Defined mixtures were consistently and accurately identified by fragment analysis at a 5% relative concentration of mutant to wild-type, and at 10% and 20% ratios by conventional PCR and direct sequencing, respectively. No false positivity was identified. Among 481 AML specimens, 40.1% (193/481) had FLT3-ITD mutations. The mutant allele burden (1.7-94.1%; median, 28.2%) and repeated length of the mutation (14-153 bp; median, 49 bp) were variable. The concordance rate between fragment analysis and conventional PCR was 97.7% (470/481). Fragment analysis was more sensitive than conventional PCR and detected 11 additional cases: seven had mutations below 10%, three cases represented conventional PCR failure, and one case showed false negativity because of short ITD length (14 bp). CONCLUSIONS: The new fragment analysis method proved to be sensitive and reliable for the detection and monitoring of FLT3-ITD in patients with AML. This could be used to simultaneously assess ITD mutant allele burden and length.

Estudio del ratio de FLT3-ITD como factor pronóstico en leucemias agudas mieloides: primeros casos estudiados en Uruguay / Analysis of the FLT3-ITD ratio as a prognostic factor in acute myeloid leukemias. First cases studied in Uruguay

Introducción: en los últimos años ha existido un avance significativo en el conocimiento biológico de la leucemia aguda mieloide (LAM) que se ha traducido en que el tratamiento de los pacientes afectados se realice guiado por el perfil citogenético y molecular. Las duplicaciones internas en tándem del gen FLT3 (FLT3-ITD) representan las mutaciones más frecuentes en LAM y confieren un mal pronóstico en pacientes con riesgo citogenético intermedio. Se ha reportado que la presencia de un ratio FLT3-ITD elevado (relación entre cantidad de alelo portador de ITD y de alelo salvaje) confiere un mayor pronóstico adverso. Objetivo: estandarizar una técnica, no disponible en Uruguay, para determinar el ratio de FLT3-ITD en pacientes portadores de LAM de riesgo citogenético intermedio. Discutir los primeros casos de LAM FLT3+ a los que se realizó el ratio. Material y método: para la detección de FLT3-ITD se amplificó un fragmento correspondiente a los exones 14 y 15 del gen en muestras de médula ósea al debut de la enfermedad. En los casos positivos se determinó el ratio de FLT3-ITD mediante análisis de fragmentos por electroforesis capilar. Resultados: en este trabajo mostramos la estandarización de un método para la determinación del ratio de FLT3-ITD y los primeros casos analizados en nuestro país. Se estudiaron 12 pacientes y se detectó la presencia de FLT3-ITD en tres de ellos. El ratio de FLT3-ITD encontrado fue en dos casos menor a 0,8 y en un caso mayor o igual a 0,8. Conclusiones: disponemos de una técnica de determinación del ratio de FLT3-ITD con importante valor pronóstico para pacientes portadores de LAM.

Abstract Introduction: In recent years, significant progress has been made in the biological knowledge of acute myeloid leukemia (AML), which has been reflected on treatment of affected patients being guided by cytogenetics and molecular profiling. FLT3 internal tandem duplications (FLT3/ITDs) represent the most frequent mutations in AML and confer a bad prognosis in patients with intermediate cytogenetic risk. It has been reported that the presence of a high FLT3-ITD ratio (relationship between number of ITD carrier allele and wild type allele). Objective: To standardize a technique, still not available in Uruguay, to determine the FLT3-ITD ratio in patients carriers of AML of intermediate cytogenetic risk. To discuss the first cases of AML FLT3+ who underwent ratio analysis. Methods: In order to identify FLT3-ITD, the fragment corresponding to exons 14 and 15 of the gene was amplified in bone marrow samples upon debut of the disease. In the cases it was positive, the FLT3-ITD ratio was determined by the analysis of fragments with capillary electrophoresis. Results: This study presented the standardization of a method to determine the FLT3-ITD ratio and the first cases analysed in our country. Twelve patients were studied and the presence of FLT3-ITD was detected in three of them. In two cases, the FLT3-ITD ratio found was below 0.8 and in one case it was greater than or equal to 0.8. Conclusions: We have a technique to determine the FLT3-ITD ratio with an important prognostic value for patients carriers of AML.

Resumo Introdução: nos últimos anos observou-se um avanço significativo do conhecimento biológico da leucemia aguda mieloide (LAM) que fez com que o tratamento destes pacientes seja orientado por seus perfis citogenético e molecular. As duplicações internas no tandem do gen FLT3 (FLT3-ITD) são as mutações mais frequentes na LAM e conferem um mal prognóstico em pacientes com risco citogenético intermediário. Foi descrito que uma proporção de FLT3-ITD elevada (relação entre a quantidade do alelo portador de ITD e do alelo selvagem) está vinculada com um maior prognóstico adverso. Objetivo: padronizar uma técnica, não disponível no Uruguai, para determinar a proporção de FLT3-ITD em pacientes portadores de LAM com risco citogenético intermediário. Discutir os primeiros casos de LAM FLT3+ cuja proporção foi calculada. Materiais e métodos: para a detecção de FLT3-ITD, foi realizada a ampliação de um fragmento correspondente aos exons 14 e 15 do gen em amostras de medula óssea no inicio da doença. Nos casos positivos, a proporção de FLT3-ITD foi determinada usando análise de fragmentos por eletroforese capilar. Resultados: neste trabalho mostramos a padronização de um método para a determinação da proporção de FLT3-ITD e os primeiros casos estudados no nosso país. Foram estudados 12 pacientes e a presença de FLT3-ITD foi determinada em 3. Em dois casos a proporção de FLT3-ITD era menor que 0,8 e em 1 caso maior ou igual a 0,8. Conclusões: contamos com uma técnica de determinação da proporção de FLT3-ITD com importante valor prognóstico para pacientes portadores de LAM.

High fms-like tyrosine kinase-3 (FLT3) receptor surface expression predicts poor outcome in FLT3 internal tandem duplication (ITD) negative patients in adult acute myeloid leukaemia: a prospective pilot study from India.

Background & objectives: Mutations in fms-like tyrosine kinase 3 (FLT3) receptor have significant role in assessing outcome in patients with acute myeloid leukaemia (AML). Data for FLT3 surface expression in relation to FLT3 internal tandem duplication (ITD) status and outcome are not available from India. The objective of the current study was to investigate adult patients with AML for FLT3 expression and FLT3 ITD mutation, and their association with long-term outcome. Methods: Total 51 consecutive de novo AML patients aged 18-60 yr were enrolled in the study. FLT3 ITD was detected by polymerase chain reaction (PCR); flowcytometry and qPCR (Taqman probe chemistry) were used for assessment of FLT3 protein and transcript, respectively. Kaplan Meier curves were obtained for survival analysis followed by log rank test. Results: FLT3 ITD was present in eight (16%) patients. Complete remission was achieved in 33 (64.6%) patients. At 57.3 months, event free survival (EFS) was 26.9±6.3 per cent, disease free survival (DFS) 52.0±9.2 per cent, and overall survival event (OS) 34.5±7.4 per cent. FLT3 surface expression was positive (>20%) by flow-cytometry in 38 (88%) of the 51 patients. FLT3 surface expression and transcripts were not associated with FLT3 ITD status. FLT3 expression was significantly associated with inferior EFS (P=0.026) and OS (P=0.018) in those who were negative for FLT3 ITD. Interpretation & conclusions: This study evaluated FLT3 ITD mutation along with FLT3 expression in AML patients, and associated with survival. Negative impact of FLT3 surface expression on survival was observed in AML patients who were FLT3 ITD negative.

Detection and clinical research of FMS-like tyrosine kinase-3, NPM1 and c-kit genes in bone marrow slides of patients with acute myeloid leukemia / 白血病·淋巴瘤

Objective To study the FMS-like tyrosine kinase-3 (FLT3) gene, NPM1 gene and c-kit gene mutations in acute myeloid leukemia (AML) by extracting DNA from the storage of bone marrow slides, and to investigate the relationship between the three gene mutations and clinical features in AML. Methods The bone marrow slides of 55 patients diagnosed with AML were enrolled in this study. The PCR, DNA sequencing and molecular cloning were used to detect and analyse the FLT3-ITD, NPM1 and c-kit gene mutations. Patients' remission, progression and survival time were also recorded. Results The DNA was successfully extracted from the bone marrow slides with -20 ℃ frozen storage without Wright stained, chemically fixed, and room temperature storage Wright stained discoloured by phenol ∶ chloroform ∶ isoamyl alcohol method, which can be used in PCR, direct sequencing and molecular cloning sequencing analysis. 10 of the 55 cases (18.2 %) were FLT3-ITD positive, including 9 cases with heterozygous mutations and 1 case with homozygous mutation. FLT3-ITD positive group had lower complete remission (CR) rate, shorter event-free survival (EFS) time and overall survival (OS) time than the negative group (P< 0.05). 9 of the 55 cases (16.4 %) had NPM1 heterozygous gene mutations, all belonging to type A. The EFS rate of the patients with NPM1 mutation was higher in 10 months and the OS rate was higher in 19 months (P< 0.05). 3 of 9 NPM1 mutations patients were FLT3-ITD positive. The CR rates of the four groups after initial remission induction therapy in order were NPM1+FLT3-ITD-, NPM1-FLT3-ITD-, NPM1-FLT3-ITD+, NPM1+FLT3-ITD+(P<0.05). Besides, NPM1-FLT3-ITD+was a risk factor affecting the OS (RR=1.250, P=0.005). 2 of the 55 cases (3.6 %) had c-kit gene mutations, namely mutant D816H and mutant D816V. The c-kit gene mutations were not found in patients with FLT3-ITD and NPM1 mutations. Conclusions The FLT3-ITD mutation is a poor prognosis molecular marker in AML, and NPM1 mutation is a good factor for the prognosis. NPM1-FLT3-ITD+is a risk factor affecting OS. The rate of c-kit gene mutation is low in AML, without the overlap of FLT3 and NPM1 mutations.

Expression of eIF4E in acute myeloid leukemia / 白血病·淋巴瘤

Objectives To analysis the expression difference of eIF4E in bone marrow between the acute myeloid leukemia (AML) and the non-tumor patient,before and after induction therapy,and the different subtypes of AML,and to explore the relation between eIF4E and other molecular biology abnormalities in AML.Methods The bone marrow specimens of newly diagnosed AML and non-tumor control patients were collected.The expression level of eIF4E was detected by RT-PCR.Results The positive rate of eIF4E was 65.2 ％ (101/155) in AML.eIF4E turned to negative in 12 patients (17.6 ％) who got complete remission after induction therapy.eIF4E was negatively expressed in bone marrow of the nontumor control patients.The positive rates of eIF4E were 75.0 ％ (15/20) and 80.8 ％ (21/26) in M4 and M5 type AML,respectively,and was 59.6 ％ (65/109) in other subtype AML (P ＞ 0.05).FLT3/ITD gene mutation was found in 26 cases of newly diagnosed AML.The eIF4E expression and FLT3-ITD gene mutation were independent each other (P ＞ 0.05).Conclusions eIF4E is positive in most of the newly diagnosed AML and turns to negative in part of AML achieving complete remission.The expression of eIF4E is no difference among different subtype of AMLs.eIF4E and FLT3-ITD gene mutation are independent each other.