Amount of bone marrow blasts is strongly correlated to NPM1 and FLT3-ITD mutation rate in AML with normal karyotype

The potential role of nucleophosmin (NPM1) in the development of cancer

Nucleophosmin (NPM1) is a well-known nucleocytoplasmic shuttling protein that performs several cellular functions such as ribosome biogenesis, chromatin remodeling, genomic stability, cell cycle progression, and apoptosis. NPM1 has been identified to be necessary for normal cellular functions, and its altered regulation by overexpression, mutation, translocation, loss of function, or sporadic deletion can lead to cancer and tumorigenesis. In this review, we focus on the gene and protein structure of NPM1 and its physiological roles. Finally, we discuss the association of NPM1 with various types of cancer including solid tumors and leukemia.

The incidence and prognostic effect of Fms-like tyrosine kinase 3 gene internal tandem and nucleolar phosphoprotein 1 genes in acute myeloid leukaemia: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Molecular genotyping is an important prognostic role in acute myeloid leukemia (AML) patients. We aimed to design this meta-analysis to discuss the incidence and prognostic effect of nucleolar phosphoprotein 1 (NPM1) and Fms-like tyrosine kinase 3 gene internal tandem (FLT3-ITD) gene in AML patients.

METHODS

PubMed, Embase, Medline, and Cochrane library were systematically searched due to May 15, 2020. Four combinations of genotypes (FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, FLT3-ITDpos/NPM1wt) were compared in association with the overall survival (OS) and leukemia-free survival (LFS) outcome, which expressed as pooled hazard ratio (HR) and 95% confidence intervals (CIs).

RESULTS

Twenty-eight studies were included in our study. The incidence of FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, and FLT3-ITDpos/NPM1wt was 16%, 13%, 50%, and 10%, respectively. The patients with FLT3-ITDneg/NPM1mut gene may have the best OS and LFS when comparing with FLT3-ITDpos/NPM1mut (HR = 1.94 and 1.70, P < .01), FLT3-ITDneg/NPM1wt (HR = 1.57 and 2.09, P < .01), and FLT3-ITDpos/NPM1wt (HR = 2.25 and 2.84, P < .001).

CONCLUSION

AML patients with FLT3-ITDneg/NPM1mut gene type have the best survival outcome than the other 3 gene types, which should be an independent genotyping in AML classification.

The Association of FLT3-ITD Gene Mutation with Bone Marrow Blast Cell Count, CD34, Cyclin D1, Bcl-xL and hENT1 Expression in Acute Myeloid Leukemia Patients

Background & Objective:

FLT3-ITD has been recently used as a molecular prognostic marker for risk classification in acute myeloid leukemia (AML) therapy. In this study we aimed to investigate the association of FLT3-ITD gene mutation with bone marrow blast cell count, CD34 expression as malignant cell burden, cyclin D1 and Bcl-xL expressions as indexes of cell proliferation and anti-apoptosis and human equilibrative nucleoside transporter 1 (hENT1) expression as cytarabine transporter during AML treatment.

Methods:

We investigated FLT3-ITD mutations, bone marrow blast cell count, CD34, cyclin D1, Bcl-xL and hENT1 expression in bone marrow aspirates from 22 de novo AML patients in a cross sectional study.

Results:

FLT3-ITD mutations were observed in 5 out of 22 de novo AML patients (22.7%). Patient with FLT3-ITD mutations had higher blast cell counts (79.5% vs 56.1%, P=0.004). In patients with FLT3-ITD mutations, CD34 and cyclin D1 expressions were higher (MFI 328.80 vs 25.78, P=0.003 and MFI 74.51 vs 57.15 P=0.005) than the patients without mutations. hENT1 expression in AML with FLT3-ITD mutation was lower (MFI 29.64 versus 56.32, P=0.0000) than in mutation-free AML. There was no significant difference in Bcl-xL expression between patients with and without mutations (P=0.61).

Conclusion:

A significant association was found between FLT3-ITD gene mutations in AML patients with bone marrow blast cell count, CD34, cyclin D1 and hENT1 expressions, however no association was obtained with Bcl-xL expression. These findings support the role of such mutation in pathogenesis of AMLand its contribution in rearrangement of standard therapy with cytarabine in management of AML.

Clonal hematopoiesis and measurable residual disease assessment in acute myeloid leukemia

Current objectives regarding treatment of acute myeloid leukemia (AML) include achieving complete remission (CR) by clinicopathological criteria followed by interrogation for the presence of minimal/measurable residual disease (MRD) by molecular genetic and/or flow cytometric techniques. Although advances in molecular genetic technologies have enabled highly sensitive detection of AML-associated mutations and translocations, determination of MRD is complicated by the fact that many treated patients have persistent clonal hematopoiesis (CH) that may not reflect residual AML. CH detected in AML patients in CR includes true residual or early recurrent AML, myelodysplastic syndrome or CH that is ancestral to the AML, and independent or newly emerging clones of uncertain leukemogenic potential. Although the presence of AML-related mutations has been shown to be a harbinger of relapse in multiple studies, the significance of other types of CH is less well understood. In patients who undergo allogeneic hematopoietic cell transplantation (HCT), post-HCT clones can be donor-derived and in some cases engender a new myeloid neoplasm that is clonally unrelated to the recipient's original AML. In this article, we discuss the spectrum of CH that can be detected in treated AML patients, propose terminology to standardize nomenclature in this setting, and review clinical data and areas of uncertainty among the various types of posttreatment hematopoietic clones.

[Analysis of induction efficacy and prognostic factors in FLT3-ITD positive acute myeloid leukemia in the real world]

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 (χ(2)=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.

FMS-Like Tyrosine Kinase 3 (FLT3) and Nucleophosmin 1 (NPM1) in Iranian Adult Acute Myeloid Leukemia Patients with Normal Karyotypes: Mutation Status and Clinical and Laboratory Characteristics

Objective:

In this study, we evaluated the frequency of FMS-like tyrosine kinase 3 (FLT3-ITD and FLT3-TKD) and nucleophosmin (NPM1) mutations in Iranian patients with cytogenetically normal acute myeloid leukemia (CN-AML). The clinical and laboratory characteristics were compared between wild-type and mutant cases.

Materials and Methods:

Seventy newly diagnosed de novo AML patients were recruited at the time of diagnosis prior to chemotherapy; among them, 54 had CN-AML. For detecting mutations, the FLT3 and NPM1 genes were amplified by the polymerase chain reaction method, followed by direct sequencing.

Results:

Our results showed that the frequencies of FLT3-ITD, FLT3-TKD, and NPM1 mutations in CN-AML patients were 25.9%, 5.9%, and 20.8%, respectively. The most frequent NPM1 mutation type was the type A mutation. The FLT3-ITD mutation was seen more frequently in non-M3 patients compared with M3 patients. No mutation was observed in either the FLT3-TKD or the NPM1 gene in patients in the M3 French-American-British group. There was no significant association between the presence of FLT3-ITD and NPM1 mutations in CN-AML patients (p>0.05). The frequency of FLT3-ITD, FLT3-TKD, and NPM1 mutation was higher in CN-AML patients in comparison with AML patients with cytogenetic aberrations, although the differences were not statistically significant (p>0.05). There were no significant differences in mean white blood cell and platelet counts, serum hemoglobin levels, and bone marrow blast percentages between patients with wild-type and mutant FLT3-ITD and NPM1 genes (p>0.05). No difference was observed in the frequency of FLT3-ITD or NPM1 mutation regarding age or sex (p>0.05).

Conclusion:

Given the high stability of NPM1 during the disease course, it can be used in combination with FLT3 as well as other known genetic markers to monitor patients, especially for minimal residual disease detection.

[Efficacy and safety of Sorafenib as monotherapy to FLT3-ITD positive acute myeloid leukemia]

Objective: To explore the efficacy and safety of Sorafenib as monotherapy to FLT3 positive acute myeloid leukemia (AML). Methods: From April 2014 to December 2015, fourteen AML patients with FLT3 positive, 7 males and 7 females with a median age of 42 (range: 14-81) years old, were enrolled in this study. Of the 14 cases, 4 were de novo cases, 9 refractory cases and 1 relapsed case, including 78.6% patients with severe complications and 57.1% patients with KPS score less than 60 [the median KPS score was 45 (20-70) ]. The administration of Sorafenib was 400 mg twice daily and Sorafenib was continued if tolerated. The treatment response was evaluated by MICM and the data were analyzed by paired samples t test before and after Sorafenib treatment. Results: The peripheral blood WBC count [4.2 (0.9-11.8) ×109/L vs 39.6 (2.3-209.5) ×109/L, P<0.001 ], the percentage of peripheral blast cell [0.07 (0-0.54) vs 0.53 (0-0.94), P<0.001] and the percentage of bone marrow blast cell [0.266 (0.020-0.880) vs 0.604 (0.180-0.900), P=0.003] were significantly decreased after Sorafenib monotherapy compared with before. The overall response rate was 57.1% (8/14), including 5 cases (35.7%) with complete remission (CR). Of 4 de novo cases, 2 achieved CR, 1 with PR, 1 with NR; 3 of 10 refractory and relapsed patients achieved CR and 2 cases achieved PR, 5 cases NR. The median duration of achieving molecular remission (FLT3-ITD negative) after Sorafenib was 46(33-72) days, and the median progression free survival (PFS) was 53 (28-175) days. Conclusion: Sorafenib shows activity in FLT3-ITD mutation positive AML patients. Sorafenib monotherapy could be used as a treatment option for elderly patients or patients with severe complications, and refractory and relapsed patients with not suitable for intensive chemotherapy.

Acute monocytic leukaemia with t(11; 12) (p15; q13) chromosomal changes: A case report and literature review

Acute myeloid leukaemia (AML) is a type of heterogeneous disease derived from haematopoietic stem cells. Cytogenetic characterisation is essential for diagnosis and prognosis stratification. Here, we present the case of a 43-year-old female diagnosed with leukaemia, who demonstrated a rare chromosomal change of t(11; 12) (p15; q13) along with a positive FLT3-ITD mutation. The patient had a white blood cell count of 76.41×10⁹/l. Bone marrow morphology revealed that monoblasts accounted for 25.5% of cells, and premonocytes accounted for 49.0%. This patient strongly responded to idarubicin and Ara-c (cytarabine) chemotherapy, which rapidly eliminated the leukaemia cell clones. However, the proliferation rate of the leukaemia cells was high during the intermission of chemotherapy. Subsequently, following two courses of chemotherapy, full haematological remission could not be attained. AML patients with t(11; 12) (p15; q13) combined with FLT3-ITD mutations are expected to have a short life expectancy; however, early haematopoietic stem cell transplantation therapy may improve the treatment outcome for these patients.

Associations between age, cytogenetics, FLT3-ITD, and marrow leukemia cells identified by flow cytometry

OBJECTIVES

To explore the relationships between age, cytogenetic subgroups, molecular markers, and cells with leukemic aberrant immunophenotype in patients with acute myeloid leukemia (AML).

METHODS

In this study, we evaluated the correlations between age, cytogenetic subgroups (normal, balanced and unbalance karyotype), molecular mutations (NPM1, FLT3-ITD, and CEBPA mutations) and marrow leukemia cells (LC) identified by flow cytometry in 256 patients with de novo AML.

RESULTS

From age group 10-19 years to age group ≥ 60 years, the percentage of LC decreased from 67.0 ± 18.4% to 49.0 ± 25.1% (F = 2.353, P = 0.041). LC percentage was higher in patients with balanced karyotypes (65.7 ± 22.4%), than those with unbalanced karyotypes (46.0 ± 26.6%) (u = 3.444, P = 0.001) or a normal karyotype (49.9 ± 22.1%) (u = 5.093, P < 0.001). Patients with FLT3-ITD (64.3 ± 19.5%) had higher LC percentages compared with those without (54.2 ± 24.3%) (u = 2.794, P = 0.007).

CONCLUSIONS

Associations between age, cytogenetics, molecular markers, and marrow leukemia cells may offer beneficial information to understand the biology and pathogenesis of AML.

NPM1, FLT3-ITD, CEBPA, and c-kit mutations in 312 Chinese patients with de novo acute myeloid leukemia

OBJECTIVES

To explore NPM1, FLT3-ITD, CEBPA, and c-kit mutations in patients with acute myeloid leukemia (AML) from Chinese population.

METHODS

In this study, we retrospectively analyzed the prevalence and clinical profile of NPM1, FLT3-ITD, CEBPA, and c-kit mutations in 312 patients with de novo AML.

RESULTS

The frequencies of NPM1, FLT3-ITD, c-kit, and CEBPA mutations were 15.4, 14.0, 7.64, and 25.6%, respectively. The occurrence rate of NPM1 mutations increased with age in patients younger than 60 years. NPM1, c-kit, and CEBPA mutations were all associated with French-American-British subtypes. Patients with NPM1 mutations and FLT3-ITD presented with higher peripheral white blood cell counts and marrow blast percentages.

CONCLUSION

Both this and previous studies may suggest low frequencies of NPM1 and FLT3-ITD mutations in AML patients from the Chinese population, and they may have a synergistic function in stimulating proliferation of leukemia cells.

CD123 immunohistochemical expression in acute myeloid leukemia is associated with underlying FLT3-ITD and NPM1 mutations

FLT3-ITD and NPM1 mutation testing in acute myeloid leukemia (AML) plays an important role in prognostic risk stratification, especially within the intermediate cytogenetic risk group. Molecular studies require adequate fresh material and are typically performed on a dedicated aspirate specimen, which may not be available in all cases. Prior flow cytometric studies have suggested an association between CD123 overexpression in AML and FLT3-ITD and/or NPM1 mutations; however, the immunohistochemical (IHC) correlate is unknown. We assessed CD123 IHC expression in 157 AML bone marrow biopsies and/or marrow particle preparations, and correlated with the morphologic, immunophenotypic, and cytogenetic features and with the presence of FLT3-ITD and NPM1 mutations. We found that CD123 IHC expression, seen in 40% of AML, occurred across a wide spectrum of 2008 World Health Organization subtypes and was most frequent within the intermediate risk group. As compared with CD123 IHC-AML, CD123 IHC+AML demonstrated higher marrow blast percentages (median 69%), monocytic differentiation (33/63 cases), and CD34 negativity (29/63 cases). Eighty-three percent (25/30) FLT3-ITD-mutated AML were CD123+ (P<0.0001) and 62% (18/29) NPM1-mutated cases were CD123 IHC+ (P=0.0052) with negative predictive values of 95% for FLT3-ITD and 88% for NPM1. CD123 IHC+AML presents with characteristic pathologic features, some of which may be related to underlying FLT3-ITD and/or NPM1 mutations.

Age-specific distributions of cytogenetic subgroups of acute myeloid leukemia: data analysis in a Chinese population

Although some studies have reported relationships between cytogenetic subgroups, molecular markers and age in acute myeloid leukemia (AML), conclusions based on data from a Chinese population are lacking. In the present study, we evaluated 640 patients with de novo AML. The patients were divided into 8 age groups, i.e. 0-9, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69 and ≥70 years, and were then classified into cytogenetic groups based on normal, balanced and unbalanced karyotypes.