FLT3 Gene Mutations Research Articles

Identification of a novel mutation of the FLT3 gene located on the juxtamembrane domain from acute myeloid leukemia patients.

FLT3 gene mutations are genetic abnormality that caused leukemogenesis. Furthermore, presence of FLT3 mutations is associated with poor prognosis in AML. This study aimed to identify FLT3 gene mutations so that it can be used as a genetic reference for the AML patients in Indonesian population. This cross-sectional study recruited 63 AML de novo patients between August 2021 and July 2023 at Cipto Mangukusumo General Hospital and Dharmais Cancer Hospital. We collected peripheral blood from the patients for DNA isolation. FLT3 gene mutation was detected using PCR method, then followed by the Sanger sequencing. Novel mutation in exon-14 continued to in silico study using SWISS MODEL server for modelling protein and PyMOL2 software for visualizing the protein model. Frequency FLT3-ITD mutation was 22% and 6 (10%) patients had a novel mutation on juxtamembrane domain. The number of FLT3-ITD insertions was 24bp to 111bp, with a median of 72bp. Novel mutation indicated a change in the protein sequence at amino acid number 572 from Tyrosine to Valine and formed a stop codon (UGA) at amino acid position ins572G573. In-silico study from novel mutation showed the receptor FLT3 protein was a loss of most of the juxtamembrane domain and the entire kinase domain. A novel FLT3 gene mutation was found in this study in the juxtamembrane domain. Based on the sequencing analysis and in silico studies, this mutation is likely to affect the activity of the FLT3 receptor. Therefore, further studies on this novel mutation are needed.

Current knowledge about FLT3 gene mutations, exploring the isoforms, and protein importance in AML.

Acute myeloid leukaemia (AML) is a complex haematological malignancy characterised by diverse genetic alterations leading to abnormal proliferation of myeloid precursor cells. One of the most significant genetic alterations in AML involves mutations in the FLT3 gene, which plays a critical role in haematopoiesis and haematopoietic homeostasis. This review explores the current understanding of FLT3 gene mutations and isoforms and the importance of the FLT3 protein in AML. FLT3 mutations, including internal tandem duplications (FLT3-ITD) and point mutations in the tyrosine kinase domain (FLT3-TKD), occur in 25-30% in AML and are associated with poor prognosis. FLT3-ITD mutations lead to constitutive activation of the FLT3 signalling pathway, promoting cell survival and proliferation. FLT3-TKD mutations affect the tyrosine kinase domain and affect AML prognosis in various ways. Furthermore, FLT3 isoforms, including shorter variants, contribute to the complexity of FLT3 biology. Additionally, nonpathological polymorphisms in FLT3 are being explored for their potential impact on AML prognosis and treatment response. This review also discusses the development of molecular treatments targeting FLT3, including first-generation and next-generation tyrosine kinase inhibitors, highlighting the challenges of resistance that often arise during therapy. The final chapter describes FLT3 protein domain rearrangements and their relevance to AML pathogenesis.

FLT3 and IRAK4 Inhibitor Emavusertib in Combination with BH3-Mimetics in the Treatment of Acute Myeloid Leukemia.

Targeting the FLT3 receptor and the IL-1R associated kinase 4 as well as the anti-apoptotic proteins MCL1 and BCL2 may be a promising novel approach in the treatment of acute myeloid leukemia (AML). The FLT3 and IRAK4 inhibitor emavusertib (CA4948), the MCL1 inhibitor S63845, the BCL2 inhibitor venetoclax, and the HSP90 inhibitor PU-H71 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells in vitro. AML cells represented all major morphologic and molecular subtypes, including FLT3-ITD and NPM1 mutant AML cell lines and a variety of patient-derived AML cells. Emavusertib in combination with MCL1 inhibitor S63845 or BCL2 inhibitor venetoclax induced cell cycle arrest and apoptosis in MOLM-13 cells. In primary AML cells, the response to emavusertib was associated with the presence of the FLT3 gene mutation with an allelic ratio >0.5 and the presence of NPM1 gene mutations. S63845 was effective in all tested AML cell lines and primary AML samples. Blast cell percentage was positively associated with the response to CA4948, S63845, and venetoclax, with elevated susceptibility of primary AML with blast cell fraction >80%. Biomarkers of the response to venetoclax included the blast cell percentage and bone marrow infiltration rate, as well as the expression levels of CD11b, CD64, and CD117. Elevated susceptibility to CA4948 combination treatments with S63845 or PU-H71 was associated with FLT3-mutated AML and CD34 < 30%. The combination of CA4948 and BH3-mimetics may be effective in the treatment in FLT3-mutated AML with differential target specificity for MCL1 and BCL2 inhibitors. Moreover, the combination of CA4948 and PU-H71 may be a candidate combination treatment in FLT3-mutated AML.

Unpredicted transformation of acute myeloid leukemia with translocation (16;16) (p13; q22): a case report and review of the literature

IntroductionThe transformation of acute myeloid leukemia with translocation (16;16) (p13; q22) from AML M2 to acute monocytic leukemia (AML M5) during therapy is a rare clinical occurrence, and this is the first time it has been reported.Clinical complainA 19-year-old male patient was admitted for severe fatigue with anemic manifestation and weight loss, for more than 1 month, with exacerbation of the condition in the last 2 days.DiagnosisA primary diagnosis was made for AML M2 with t (16;16) (p13; q22) established on bone marrow (BM) morphology. A consequential detection of FLT-3 ITD mutation was done. At day 28 follow-up after induction and maintenance therapy, the diagnosis of AML M2 was maintained with a high bone marrow (BM) blast count, prompting the initiation of a more aggressive treatment protocol. After 1 month of implementing the recent protocol, the patient remains morphologically resistant with a notable transformation of bone marrow infiltration by an abnormal monocytic population (monoblasts and promonocytes). The final diagnosis of transforming FLT3-mutated AML with t (16;16) (p13; q22) was established.InterventionAfter the initial diagnosis of AML M2 with t (16;16) (p13; q22), the patient received the 3 + 7 induction protocol. The 2nd induction protocol initiated after the second evaluation and morphological resistance was the FLAG Adrian protocol. The 3rd protocol after transformation to AML M5 was 1 cycle of the MEC protocol. Anti-FLT3 treatment was considered.OutcomesThe patient was maintained on the 3rd protocol of chemotherapy. Unfortunately, he was admitted to the ICU unit complaining of neutropenic fever and severe sepsis where he died before final re-evaluation and the anti-FLT3 treatment initiation.ConclusionAML with t (16;16) (p13; q22) characterized by favorable outcome. However, identifying additional chromosome abnormality or genetic aberration, especially FLT3 gene mutation, is recognized as an important factor influencing final disease outcome. Therefore, early detection of FLT3 mutations will allow comprehensive disease course prediction and targeted therapy that might achieve longer and more durable remissions.

Clinical analysis of 82 cases of acute promyelocytic leukemia with PML-RARα short isoform in children and adults.

Acute promyelocytic leukemia (APL) with PML/RARα fusion gene is a distinct variant of acute myeloid leukemia. According to the different break sites of the PML gene, there are three transcripts: Long (bcr1), Variant (bcr2) and Short (bcr3). We retrospectively analyzed 82 APL cases with PML-RARα short isoform. A total of 384 patients with APL were seen, of which 85(22.14%) had PML/RARα short isoform (bcr3) and 82 met the inclusion criteria. The median age was 33.5 years (range, 2-72 years). The incidences of hemorrhage in the intermediate- and high-risk group were higher, but only the incidence between medium and low risk differed statistically (P=0.006), and the incidences of fever, fatigue, splenomegaly, and lymph node enlargement and differentiation syndrome (DS) in those groups were not statistically significant (P>0.05). FLT3 gene mutation rate and the mortality rate of the high-risk group were significantly higher than that of other groups (P=0.040 and P=0.004, P=0.041 and P=0.037, respectively). The mortality rate was lowest (4.26%) in the group treated with ATRA combined with arsenic and anthracycline. The 3-year OS and the 3-year DFS of the low and intermediate-risk group were better (P=0.019 and P=0.017, respectively). ATRA combined with arsenic and anthracycline had significant impact on outcomes in APL with PML-RARα short isoform.

RISK FACTORS AND EARLY SIGNS OF CRITICAL CONDITIONS IN CHILDREN WITH ACUTE LYMPHOBLASTIC LEUKEMIA ADMITTED TO THE INTENSIVE CARE UNIT

Relevance: Acute lymphoblastic leukemia (ALL) is the most common cancer among children, accounting for nearly a quarter of all childhood cancers.&#x0D; The study aimed to determine the risk factors and signs of critical conditions in children with acute lymphoblastic leukemia admitted to an intensive care unit (ICU).&#x0D; Methods: The approach used was a systematic review. Data was collected from sources published in 2019-2023. Four cohort studies, four retrospective analyses, two literature reviews, one case-control study, and one case study were included in this systematic review.&#x0D; Results: The prognosis in pediatric ALL depends on the initial number of blast cells in the peripheral blood. Patients with B-cell precursor acute lymphoblastic leukemia (BCP ALL) and low blast cell numbers survived better than patients with T-cell acute lymphoblastic leukemia (T-ALL) and low cell count. IL1B and NLRP1 genetic polymorphisms enhanced ALL risk and reduced infectious comorbidity. However, these gene polymorphisms must be confirmed in juvenile leukemia. KRAS, FLT3, NRAS, PTPN11, KMT2D, PTEN, and NOTCH1 gene mutations affected pediatric ALL patient features and treatment results. These mutations demonstrate the relevance of genetic profiling in risk classification and tailored management. Gene variations and availability of effective medication contributed. Pediatric BCP-ALL patients with the PAX5P80R mutation had worse 5-year overall survival, higher white blood cell counts, male preponderance, and more genetic abnormalities. Pediatric BCP-ALL focused on genetic analysis and risk stratification. Children of African American and European American ancestry showed varied incidence, recurrence, and outcome rates for ALL. African American children exhibited lower incidence but greater recurrence rates and poorer prognosis than European American children.&#x0D; Conclusion: Risk factors for these patients’ admission to ICU include comorbidities, infectious diseases, hypoxia, and hemodynamic instability, as well as age and baseline white blood cell count at diagnosis.

A Review of FLT3 Kinase Inhibitors in AML.

Acute myeloid leukemia (AML) is a highly aggressive illness distinguished by the accumulation of abnormal hematopoietic precursors in both the bone marrow and peripheral blood. The prevalence of FLT3 gene mutations is high and escalates the probability of relapse and mortality. The survival rates for AML patients, particularly those over 65, are low. FLT3 mutation screening at diagnosis is mandatory, and FLT3 inhibitors are crucial in treating AML patients with mutations. There are two categories of FLT3 mutations: FLT3-ITD located in the juxtamembrane domain and FLT3-TKD in the tyrosine kinase domain. FLT3-ITD is the most common type, affecting nearly a quarter of patients, whereas FLT3-TKD only affects 6-8% of patients. FLT3 inhibitors are now crucial in treating AML patients with FLT3 mutations. When dealing with FLT3-mutated AML, the recommended course of treatment typically involves chemotherapy and midostaurin, followed by allogeneic hematopoietic cell transplantation (HCT) to maximize the likelihood of success. Maintenance therapy can lower the risk of relapse, and gilteritinib is a better option than salvage chemotherapy for relapsed or refractory cases. Clinical trials for new or combined therapies are the most effective approach. This review discusses treatment options for patients with FLT3-mutated AML, including induction chemotherapy and options for relapsed or refractory disease. Additional treatment options may become available as more studies are conducted based on the patient's condition and susceptibility.

The Role of CXCR1, CXCR2, CXCR3, CXCR5, and CXCR6 Ligands in Molecular Cancer Processes and Clinical Aspects of Acute Myeloid Leukemia (AML).

Acute myeloid leukemia (AML) is a type of leukemia known for its unfavorable prognoses, prompting research efforts to discover new therapeutic targets. One area of investigation involves examining extracellular factors, particularly CXC chemokines. While CXCL12 (SDF-1) and its receptor CXCR4 have been extensively studied, research on other CXC chemokine axes in AML is less developed. This study aims to bridge that gap by providing an overview of the significance of CXC chemokines other than CXCL12 (CXCR1, CXCR2, CXCR3, CXCR5, and CXCR6 ligands and CXCL14 and CXCL17) in AML's oncogenic processes. We explore the roles of all CXC chemokines other than CXCL12, in particular CXCL1 (Gro-α), CXCL8 (IL-8), CXCL10 (IP-10), and CXCL11 (I-TAC) in AML tumor processes, including their impact on AML cell proliferation, bone marrow angiogenesis, interaction with non-leukemic cells like MSCs and osteoblasts, and their clinical relevance. We delve into how they influence prognosis, association with extramedullary AML, induction of chemoresistance, effects on bone marrow microvessel density, and their connection to French-American-British (FAB) classification and FLT3 gene mutations.

Combined flow cytometry natural killer immunophenotyping and KIR/HLA-C genotyping reveal remarkable differences in acute myeloid leukemia patients, but suggest an overall impairment of the natural killer response.

Natural killer (NK) cells are key anti-tumor effectors of the innate immunity. Phenotypic differences allow us to discriminate in between three functional stages of maturation, named immature, mature and hypermature that are distinctive in terms of receptor expression, cytokine secretion, cytotoxic properties and organ trafficking. NKs display an impressive repertoire of highly polymorphic germline encoded receptors that can be either activating, triggering the effector's function, or inhibitory, limiting the immune response. In our study, we have investigated peripheral blood NK cells of acute myeloid leukemia (AML) patients. The Killer Immunoglobulin-like receptors (KIRs) and the HLA-C genotypes were assessed, as HLA-C molecules are cognate antigens for inhibitory KIRs. The AA mainly inhibitory KIR haplotype was found in a higher proportion in AML, while a striking low frequency of the 2DS3 characterized the mainly activating Bx haplotype. Flow cytometry immunophenotyping evidenced a lower overall count of NK cells in AML versus healthy controls, with lower percentages of the immature and mature subpopulations, but with a markedly increase of the hypermature NKs. The analysis of the KIR2DL1, KIR2DL2, KIR2DL3, KIR3DL1, and NKG2A inhibitory receptors surface expression revealed a remarkable heterogeneity. However, an overall trend for a higher expression in AML patients could be noticed in all maturation subpopulations. Some of the AML patients with complex karyotypes or displaying a FLT3 gene mutation proved to be extreme outliers in terms of NK cells percentages or inhibitory receptors expression. We conclude that while the genetic background investigation in AML offers important pieces of information regarding susceptibility to disease or prognosis, it is flow cytometry that is able to offer details of finesse in terms of NK numbers and phenotypes, necessary for an adequate individual evaluation of these patients.

Exome sequencing analysis of gastric primary myeloid sarcoma with monocytic differentiation with altered immunophenotype after chemotherapy: case report

BackgroundMyeloid Sarcoma with monocytic differentiation is rare and quite likely is missed by surgical pathologists. However it is frequently misdiagnosed because of its non-specific imaging and histological pattern.Case presentationWe report the case of a 64-year-old woman with gastric primary myeloid sarcoma with monocytic differentiatio. Upper endoscopy revealed a neoplastic growth at the junction of the lesser curvature and gastric antrum. Except for a slightly increased peripheral monocyte count, no abnormalities were found on hematological and bone-marrow examination. Gastroscopic biopsy showed poorly differentiated atypical large cells with visible nucleoli and nuclear fission. Immunohistochemistry showed positive CD34, CD4, CD43, and CD56 expression, and weakly positive lysozyme expression. Immune markers for poorly differentiated adenocarcinoma, malignant melanoma, and lymphohematopoietic-system tumors were negative. The final diagnosis was myeloid sarcoma with monocytic differentiation. Chemotherapy did not shrink the tumor, so, radical surgery was performed. Although the tumor morphology did not change postoperatively, the immunophenotype did. CD68 and lysozyme expression (tumor tissue markers) changed from negative and weakly positive to strongly positive, AE1/3 expression (epithelial marker) changed from negative to positive, and CD34, CD4, CD43, and CD56 expression (common in naive hematopoietic cell-derived tumors) was greatly attenuated. Exome sequencing revealed missense mutations in FLT3 and PTPRB, which are associated with myeloid sarcoma, and in TP53, CD44, CD19, LTK, NOTCH2, and CNTN2, which are associated with lymphohematopoietic tumors and poorly differentiated cancers.ConclusionWe diagnosed myeloid sarcoma with monocytic differentiation after excluding poorly differentiated adenocarcinoma, common lymphohematopoietic-system tumors, epithelioid sarcoma, and malignant melanoma. We identified that the immunophenotypic of patient had alterations after chemotherapy, and FLT3 gene mutations. We hope that the above results will improve our understanding of this rare tumor.

FLT3 Gene Mutations in Acute Myeloid Leukemia Patients in Northeast Thailand.

BACKGROUND Mutations in the FLT3 gene are associated with acute myeloid leukemia (AML). FLT3 mutations have been identified in approximately 30% of de novo AML patients, particularly those with typical karyotype and inferior prognosis. Therefore, we examined the frequencies of an internal tandem duplication (ITD) and missense mutations of the FLT3 gene and their associated clinical characteristics in patients with AML in northeast Thailand. MATERIAL AND METHODS The leftover bone marrow and/or peripheral blood specimens of 65 newly diagnosed AML patients recruited from Srinagarind Hospital, Khon Kaen University, northeast Thailand, between January 2020 and May 2021 were included in this study. FLT3-ITD and FLT3- tyrosine kinase domain (TKD) were amplified using PCR-related techniques. RESULTS The frequencies of FLT3-ITD and TKD were found to be 16.9% (11/65) and 10.8% (7/65), respectively. One patient had ITD and TKD mutations. The white blood cell count and peripheral blast percentage of FLT3-ITD-positive patients were statistically significantly higher than those of the FLT3-wild type patients, while the peripheral blast percentage of FLT3-TKD-positive patients was significantly lower. No other clinical characteristics among FLT3-positive and FLT3-wild-type patients were observed. DNA sequencing identified 4 FLT3-TKD mutations. The c.2504A>T; Asp835Val and c.2503G>C; Asp835His mutations were predicted as pathogenic mutations while the 2 novel mutations, c.2508C>A; Ile836= and c.2508C>G; Ile836Met were predicted as neutral mutations. CONCLUSIONS This study showed for the first time that FLT3-TKD mutation is common among northeast Thai AML patients. The data should prove useful for selecting efficacious targeted treatment plans for the patients.

A Phase I/II Study of Combination of ASTX727, Gilteritinib and Venetoclax in Patients with Relapsed/Refractory FLT3 Mutated Acute Myeloid Leukemia (AML) and Frontline FLT3 Mutated AML Patients Unfit for Chemotherapy

Background:FLT3 gene mutations occur in approximately 30% of patients (pts) with AML and are associated with worse survival and higher relapse risk. Gilteritinib, a selective potent oral FLT3 tyrosine kinase inhibitor (FLT3i), improves survival in pts with relapsed FLT3 mutated AML. ASTX727 is an oral fixed-dose combination of decitabine (35 mg) and cedazuridine (a cytidine deaminase inhibitor; 100 mg) approved for treating pts with myelodysplastic syndrome (MDS). We are evaluating the safety and efficacy of the combination of ASTX727, gilteritinib, and venetoclax (VEN) in pts with relapsed or refractory FLT3-mutated AML and older/unfit pts unable to receive chemotherapy. Methods: In the phase I, pts with R/R FLT3-mutated AML or high-risk (HR) MDS or chronic myelomonocytic leukemia (CMML) are eligible. FLT3-ITD and/or FLT3-TKD mutations were allowed. In the phase II, the study will also enroll newly diagnosed pts with FLT3-mutated AML ineligible for induction therapy. Pts are required to have an ECOG performance status ≤3, total bilirubin ≤2.5 x upper limit of normal (ULN), ALT/AST ≤3 x ULN, and creatinine clearance ≥30 mL/min. Hydroxyurea or 1 dose of cytarabine up to 1000 mg was allowed in pts with proliferative disease to lower white blood count to ≤ 25 x 109/L before initiation of study therapy. In the phase 1, we evaluated two dose levels of gilteritinib (80 mg and 120 mg daily) continuously with fixed dosages of ASTX727 (35/100 mg daily on days 1-5) and VEN (400 mg daily, dose adjusted for concomitant azoles, for up to 28 days). Cycles are repeated every 28 days for up to 24 cycles, followed by indefinite therapy with gilteritinib as maintenance. During cycle 1, VEN was given at a dose of 100 mg on day 1, 200 mg on day 2, and 400 mg daily onwards. Bone marrow (BM) aspiration was performed on day 21, and VEN was held in pts with BM blasts <5% or aplasia. During cycles 2-24, VEN was given at 400 mg daily (dose adjusted for concomitant azoles) on days 1-21 but dose reductions depending on tolerance were permitted. Gilteritinib continued at the enrolled dose in cycles 2-24. Results: Between 11/2021 and 6/2022, 8 patients (7 AML and 1 HR-CMML) have been enrolled in the phase 1 portion of the trial (Table 1). Their median age was 57 years (range, 38-83). Median number of prior lines of therapy was 1 (range, 1-10). Four pts (50%) had a previous allogeneic hematopoietic stem cell transplant (HSCT), 6 pts (75%) had prior treatment with hypomethylating agent (HMA)+VEN, and 3 pts (27%) received prior FLT3i. None received prior gilteritinib. Cytogenetics was diploid in 4 pts, complex in 3 pts, and miscellaneous in 1 pt. The median FLT3-ITD allelic ratio (AR) was 0.4 (range, 0.11-10.60), with 50% having a high AR (≥0.5). All pts had a FLT3-ITD mutation and no pt had a FLT3-TKD mutation. NPM1 co-mutation was present in 4 pts (50%), followed by DNMT3A (37%) and IDH2 (37%). Six pts have been enrolled on dose level 1 (gilteritinib 80 mg) and 2 pt on dose level 2 (gilteritinib 120 mg). No DLTs have been observed in either dose level. Myelosuppression was frequent, requiring dose adjustment of ASTX727 and/or VEN in cycle 2 onward in 5 pts. Grade 3 non-hematologic adverse events included: sepsis (25%), bacteremia (25%), pneumonia (13%), and other infection (25%). No tumor lysis syndrome, differentiation syndrome, or QTc prolongation was observed. The 30-day and 60-day mortality rates were 0% and 13%, respectively. The overall response rate (ORR) was 87% with 4 (50%) pts achieving CR/CRi (1 CR, 3 CRi) and 3 (37%) pts achieving MLFS. One pt withdrew from the study in cycle 1 and was not evaluable for response. The ORR in pts with prior HMA+VEN was 83% (3 CRi, 2 MLFS). Five of 7 responders (71%) achieved the best response within 1 cycle and 2 (29%) within 2 cycles. Pts received a median of 2 cycles of therapy (range, 1-6). With a median follow-up of 6 months, median overall survival was not reached (range, 1.2-8+ months), and the estimated 6-month overall survival is 70%. One responding pt proceeded to HSCT. Two pts have died, 1 in CRi due to an unknown cause, and 1 due to disease progression and sepsis. Conclusion: The combination therapy with ASTX727, VEN, and gilteritinib appears to be effective and safe in R/R FLT3 mutated AML and HR-MDS. Myelosuppression was frequent but manageable. Continued accrual is anticipated to define the optimal triplet regimen in both R/R and newly diagnosed FLT3-mutated AML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

AML-247 Specific Features of the FLT3+ Acute Myeloid Leukemia Course

Preliminary stratification into prognostic risk groups is a mandatory component of the AML patient's treatment, which allows for optimizing the intensity of chemotherapy (CT), as well as planning and justifying allogeneic hematopoietic stem cell transplantation (allo-HSCT). To evaluate the effects of the FLT3 gene mutational status and the allele burden (AB) magnitude in FLT3-ITD patients on the course of AML. Retrospective and prospective study. Study of the FLT3 gene mutational status effect on the course of the disease in 280 patients was carried out. The dynamics of the magnitude of the AB in the FLT3-ITD cases were analyzed in the context of CT, allo-HSCT, and the impact of the AB on survival rates in 91 patients. The adverse effects of FLT3 gene mutations on patients' survival rates were assessed. In the study group, the frequency of FLT3 accounted for 30.5% (FLT3-ITD-24% (48/199), the frequency of FLT3-TKD was 5.5% (11/199), the combination of FLT3-ITD and FLT3-TKD was found in 1.0% (2/199)); the rest of the patients, 69.5% (138/199), had no mutations in the FLT3 gene. Mutations in NPM1 gene were detected significantly more frequently in the FLT3-ITD-in 37 (32.4%) out of 114 patients (p=0.0001). Two groups were identified according to the magnitude of AB in the FLT3-ITD mutations: low AB (<0.5)-n=50 (55%) and high AB (≥0.5)-n=41 (45%). Patients with high AB FLT3 gene, compared with low AB, had a high level of leukocytes (p<0.001) and bone marrow blast cells (p=0.04). Patients FLT3-ITDlow/NPM1+ achieved CR (complete clinical and hematological remission) more often compared with FLT3-ITDhigh/NPM1+, with CR rate of 71.4% and 16.0%, respectively (%2=11.2; p=0.04). The efficacy of allo-HSCT in FLT3 + was significantly higher only in terms of OS; it was not achieved in the allo-HSCT(+) (n=24), compared with the median of 8 months recorded in the allo-HSCT(-) (n=119)(p<0.00001). The application of CT reduced AB by 1.5 (p<0.001). Sequential use of CT and allo-HSCT showed higher efficacy (p<0.001). AML patients with mutations in the FLT3 gene require an individualized approach with inclusion of targeted drugs into the scheme of treatment, which allows survival rates to improve.

A Coarse-to-Fine Pathology Patch Selection for Improving Gene Mutation Prediction in Acute Myeloid Leukemia.

Identifying gene mutation is essential to prognosis and therapeutic decisions for acute myeloid leukemia (AML) but the current gene analysis is inefficient and non-scalable. Pathological images are readily accessible and can be effectively modeled using deep learning. This work aims at predicting gene mutation directly by modeling bone marrow smear images. Traditionally, bone marrow smear slides are cropped into patches with manual segmentation for patch-level modeling. Slide-level modeling, such as multi-instance learning, could aggregate patches for holistic modeling, though suffer from excessive redundancy. In this study, we propose a discriminative multi-instance approach to select useful patches in a coarse-to-fine process. Specifically, we preprocess a slide into patches by using a trained pre-selector network. Then, we rule out low quality patches in the coarse selection with known prior knowledge, and refine the model using gene-discriminative patches in the fine selection. We evaluate the framework for CEBPA, FLT3, and NPM1 gene mutation prediction and obtain 71.67%, 56.26%, and 56.34% F1-score. Further analysis show the effect of different selection criteria on prediction gene mutations using pathological images.

Efficacy of midostaurin combined with intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation in a patient with NPM1 and FLT3-TKD mutated acute myeloid leukaemia with clinical high-risk features

Many genetic disorders occur in patients suffering from acute myeloid leukaemia (AML). The most common mutations found in such patients are in the nucleophosmin ( NPM ) gene and the FLT3 tyrosine kinase receptor gene. NPM1 mutation is observed in 30–35% of adult AML patients (50–60% of AML with normal karyotype), showing a favourable prognosis. The presence of point FLT3 comutations occur in the tyrosine kinase domain (TKD) are associated with even more favourable prognosis. However FLT3 comutations i.e. internal tandem duplication (ITD) in particular with high allelic ratio (ITD high ) worsen the course of leukemia and treatment outcomes. Deploying FLT3 tyrosine kinase inhibitors thus offers a prospect for improving treatment and prolonging the survival of patients with AML, burdened with the FLT3 gene mutation. Midostaurin and gilteritinib are type I FLT3 inhibitors which are used to treat patients with AML FLT3 -TKD due to their mechanism of action. This paper presents the case of a 30-year-old AML patient diagnosed with NPM1 and FLT3 -TKD mutations, bone marrow reticuline fibrosis and extramedullary sites of AML. Treatment was individualized and induction chemotherapy was combined with midostaurin. After first-line treatment with midostaurin, complete remission was achieved, as confirmed by histopathological examination of the bone marrow. Subsequently, two cycles of consolidation chemotherapy were given, and allogeneic haematopoietic stem cells were transplanted from an unrelated donor after myeloablative conditioning. The patient has remained in complete leukaemia remission, 3 years after diagnosis.

FLT3 Gene Mutation in Acute Myeloid Leukemia: Correlation with Hematological, Immunophenotypic, and Cytogenetic Characteristics

Introduction In acute myeloid leukemia (AML), FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is a common driver mutation associated with high tumor burden and poor prognosis. This mutation is common in normal karyotype AML and such patients have high leukocyte count. The presence of this mutation can be predicted by certain hematological and immunophenotypic characteristics in day-to-day practice. Objective This study was undertaken to assess the strength of association between FLT3 gene mutation and hematological and immunophenotypic characteristics. Materials and Methods Morphological, hematological, immunophenotypic, and cytogenetic characteristics of FLT3 mutations recorded in 424 patients of AML in adults and children between 2016 and 2019 in a tertiary care cancer center in Western India. Blasts were classified according to French-American-British method. Tumor burden was assessed by serum lactate dehydrogenase (LDH) levels, leucocyte count, and peripheral smear blast percentage. Results Out of 424 cases, FLT3-ITD and FLT3-tyrosine kinase domain mutation were found in 72 and 25 AML patients, respectively. Patients with FLT3 mutation had high tumor burden, characterized by high leukocyte count (p &lt; 0.001), peripheral blood (p = 0.01) and bone marrow (p = 0.03) blast percentage, and high serum LDH (mean 777.8 vs. 586; p = 0.10) compared with FLT3-negative patients. They also featured high platelet count (p &lt; 0.001). Morphological, immunophenotypic, and cytogenetic characteristics also have been presented in the study. Conclusion Observations of the study suggest the presence of definitive hematological and immunophenotypic characteristics along with raised serum LDH levels serve as surrogate markers and indicators of FLT3 mutation in AML patients.

Analysis of risk factors of relapse after allogeneic hematopoietic stem cell transplantation in patients with t (8;21) acute myeloid leukemia

目的探讨t(8;21)急性髓系白血病（AML）异基因造血干细胞移植（allo-HSCT）后复发的影响因素。方法对2008年1月至2020年10月期间在中国医学科学院血液病医院接受allo-HSCT的t(8;21) AML患者进行回顾性分析。结果73例t(8;21) AML患者纳入研究，男39例，女34例，中位年龄36（13～54）岁。73例患者中10例出现血液学复发，3年累积复发率（CIR）为15.7％（95％CI 7.3％～26.8％），中位复发时间为9.2（2.0～47.6）个月。73例患者中19例死亡，移植后3年总生存（OS）率为68.9％（95％CI 56.4％～81.4％）。移植后3个月内融合基因下降≥3个对数级组移植后3年CIR明显低于下降<3个对数级组［13.3％（95％CI 4.5％～26.8％）对57.1％（95％CI 13.2％～85.6％），P<0.001］；移植后12个月内融合基因水平下降≥4个对数级组移植后3年CIR明显低于下降<4个对数级组［5.1％（95％CI 0.9％～15.4％）对25.0％（95％CI 0.3％～71.3％），P<0.001］。Cox多因素分析显示移植当天造血干细胞回输前（0 d）RUNX1-RUNX1T1融合基因高定量（≥1.58％）［P＝0.006，HR＝28.849（95％CI 2.680～310.524）］及初诊时骨髓流式细胞术原始细胞比例≥60％［P＝0.015，HR＝6.640（95％CI 1.448～30.457）］是血液学复发的独立危险因素；c-Kit及Flt3基因突变对移植后血液学复发无明显影响（P＝0.877，P＝0.773）。初诊时骨髓流式细胞术原始细胞比例≥60％［P<0.001，HR＝8.925（95％CI 2.702～29.476）］、达到完全缓解所需的疗程数≥2个［P＝0.013，HR＝4.495（95％CI 1.379～14.649）］是影响OS的独立危险因素。结论0 d RUNX1-RUNX1T1融合基因定量水平≥1.58％及初诊时骨髓流式细胞术原始细胞比例≥60％是影响t(8;21) AML患者allo-HSCT后血液学复发的独立危险因素。移植后RUNX1-RUNX1T1融合基因监测有助于评估复发的危险性。

FLT3-ITD POSITIVITY IN AML; CASE SERIES

Diagnosis of AML requires additional procedures, including pathological examination, immunophenotyping, cytogenetic examination, and molecular diagnosis. The determination of the specific cytogenetic abnormality is important for the selection of appropriate treatment and prognostic analysis.The 2 most common mutations of the FLT3 gene are FLT3-ITD and FLT3-D835. Here, we will present FLT3-ITD positive AML cases admitted to our clinic between 2019-2021. We have 5 cases of AML FLT3-ITD heterozygous. In all our cases, Midastaurin was given with 7+3 chemotherapy (CT) in the initial treatment. While 1 of our cases went into remission, the other 4 relapsed. All of the patients who relapsed were given FLAG CT, no remission was achieved and they were switched to ADE CT. Remission was achieved in 2 of 4 patients, 2 of them were refractory. One patient was given gilteritinib. HSCT was performed in 2 patients. While 2 of our patients are dead, 2 of them are in remission and 1 of our patients is still under treatment. FLT3 gene mutations are strongly associated with leukocytosis and poor prognosis in patients with AML(1-3). Patients with any of these mutations have a higher risk of recurrence and a lower survival rate 3 . All of our patients had leukocytosis at the time of diagnosis. Four of our patients relapsed and all of these patients were refractory to chemotherapy. Our patients who were refractory to treatment had a high mortality rate (50%) and a lower survival time (8-12 months). FLT3 signaling inhibitors have been used both alone and in combination to improve clinical outcomes in patients with AML with FLT3 mutations. While inhibitor monotherapy provides clinical response, its efficacy is usually temporary and resistance develops rapidly. Various combination therapies are used to enhance efficacy and prevent or overcome resistance. More studies are needed to evaluate its efficacy and explain the development of resistance.

Prognostic Impact of Concurrent DNMT3A, FLT3 and NPM1 Gene Mutations in Acute Myeloid Leukemia Patients

BackgroundAcute myeloid leukemia (AML) is one of the rapidly progressing malignancies which is characterized by unregulated proliferation of hematopoietic precursors. Technological improvements enhanced the availability of genetic AML biomarkers. The clinical relevance of these molecular markers for AML diagnosis, planning of therapy and risk stratification are increasing evidently. MethodsIn current study, one hundred newly diagnosed AML patients before receiving induction chemotherapy were included, they were subjected to clinical examination, cytochemical and morphological analysis of blood cells, flow cytometric, cytogenetic and molecular genetic analysis for detection of NPM1, FLT3-ITD and DNMT3A mutations. Direct sequencing analysis for detection of NPM1 and DNMT3A genes mutations were done. FLT3 /ITD gene mutation was detected by gel electrophoresis after PCR amplification. ResultsAccording to genetic markers, our AML patients are classified in to further 8groups. AML patients with three DNMT3A/FLT3/NPM1 gene mutations (AML DNMT3A /FLT3/NPM1) this group of patients presented with a heavy disease burden, had an elevated WBC in comparison to other groups (70 vs. 41 × 103/μL; P = .019), and BM blast counts (71% vs. 55.6%, P < .02). When comparing eight groups for death event there were significant difference among groups; P = .005, group 1 (AML DNMT3A /FLT3/NPM1) showed rapid decline of the cumulative overall survival. There was a significant difference among 8 groups as regards response to treatment after 14 days (P = .02), group 7 AML with (DNMT3A +NMP1) gene mutations showed better response to treatment (100%), groups 1 and 3 AML with (NPM1+DNMT3A +NMP1) gene mutations and AML with isolated FLT3-ITD showed no response to treatment after 14 days. And as regards response to treatment after 28 days, the eight groups showed no significant difference (P = .14). ConclusionOur study supports adverse prognostic effect of presence of DNMT3A gene mutation either alone or in the presence of FLT3 and/or NPM1 gene mutations.

The Relationship between Body Mass Index and Adult Acute Myeloid Leukemia

To analysis the relationship between different BMI (body mass index) and the clinical characteristics, laboratory examination indexes of newly diagnosed adult patients with acute myeloid leukemia (AML), so as to investigate the effects of BMI to the efficacy of first induction chemotherapy. The clinical data of 145 newly diagnosed adult AML patients treated in the First Hospital of Lanzhou University from August 2015 to August 2019 were retrospective analyzed. According to the guidelines for prevention and control of overweight and obesity in Chinese adults, the BMI (kg/m2) of the selected AML patients before induction chemotherapy was calculated and the patients were divided into the low body mass group (BMI<18.5), the normal body mass group (18.5 ≤BMI ≤23.9) and the overweight and obese group (BMI ≥24). The clinical data of the patients, including sex, age, risk stratification,the types of leukemia, gene mutation, complications, length of hospital stay and other clinical features; white blood cell (WBC), hemoglobin (Hb), albumin, triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), low density lipoprotein (LDL), lactate dehydrogenase (LDH), and other laboratory index; agra-nulocytosis with fever, infection of etiology, lack of granulocyte duration, significant bleeding, liver and kidney toxicity of chemotherapy adverse reactions associated indicators and Morphological remission were collected. The induction chemotherapy regimen was the standard chemotherapy regimen (anthracyclines combined with cytarabine). Among the 145 newly diagnosed adult AML patients, there were 71 males and 74 females. The median age was 50 years old(range 18 to 82 years old). There were 21 patients in underweight group (14.5%), 79 patients in normal weight group (54.5%), and 45 patients in overweight and obese group (31.0%). The patients with higher BMI level showed the older in age（P=0.018）. There were significant differences in sex between the patients in each group(P=0.035). In overweight and obese patients, the number of male was significantly higher than female. There were no statistical differences in AML classification, comorbidities(Diabetes, hypertension, coronary heart disease), hospital days, whether secondary AML and FLT3 gene mutation among the patients in different BMI groups. There were significant differences in TG of the patients in the different groups, the overweight and obese patients were higher (P=0.007). There were no significant differences in WBC and Hb counts, ALB, TC, HDL, LDL, or LDH between the patients in each BMI group at newly diagnosed. The complete remission rate of the patients in the low body mass group or overweight and obese group were lower than that in the normal body weight group (P=0.035). The rate of documented infection during the first induction chemotherapy were significantly higher for the patients in low body mass group than those in normal weight group or overweight and obese group (P=0.038). There was no statistical difference in chemotherapy regimens, the number of chemotherapy until CR, febrile neutropenia, bleeding, and the time of neutropenia, liver and kidney toxicity among each BMI group. Multivariate analysis showed that overweight and obese (P=0.012) , FLT3 mutation (P=0.015) were the risk factors affecting the CR rate of the patients. And the patients with secondary AML, high-risk type, and newly diagnosed WBC ≥50×109/L showed lower CR rate, but there was no statistical difference in the patients of each group. In newly diagnosed adult patients with AML, low body mass, overweight and obesity, and FLT3 mutations were the factors reducing the early efficacy of AML patients. There were more adverse reactions induced by chemotherapy in the low body mass group. Therefore, inappropriate BMI level can be a risk factor for assessing the prognosis of adults with newly diagnosed AML.