Sujun Gao

Cytogenetic and Genetic Mutation Features of de novo Acute Myeloid Leukemia in Elderly Chinese Patients

OBJECTIVES The present study aimed to examine the cytogenetic and genetic mutation features of acute myeloid leukemia (AML) in elderly Chinese patients. METHODS A retrospective analysis of cytogenetics and genetic mutations was performed in 113 cases (age range 50-82 years) with de novo AML. RESULTS The most frequent cytogenetic abnormality was t (15;17) (q22;q21), detected in 10.0% (n = 9) of successfully analyzed cases, followed by t (8;21) (q22;q22) in 8.89% (n = 8), and complex karyotypes in 5.56% (n = 5). Those with complex karyotypes included 4 cases (4.44%) of monosomal karyotypes. The frequencies of NPM1, FLT3-ITD, c-kit, and CEBPA mutations were 27.4% (31/113), 14.5% (16/110), 5.88% (6/102), and 23.3% (7/30), respectively. The complete remission rates of patients in low, intermediate, and high risk groups were 37.5%, 48.6%, and 33.3%, respectively (χ2 = 0.704, P = 0.703) based on risk stratification. CONCLUSION Cytogenetics and genetic mutations alone may not be sufficient to evaluate the prognoses of elderly AML patients. The search for a novel model that would enable a more comprehensive evaluation of this population is therefore imperative.

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.

Characterization of IFNγ-producing natural killer cells induced by cytomegalovirus reactivation after haploidentical hematopoietic stem cell transplantation.

During human cytomegalovirus (CMV) infection after umbilical cord blood or HLA-matched hematopoietic stem cell transplantation (HSCT), a population of NKG2C-expressing natural killer (NK) cells expand and persist. The expanded NK cells express high levels of inhibitory killer immunoglobulin-like receptors (KIR) specific for self-HLA and potently produce IFNγ. However, it remains unknown whether similar events would occur after haploidentical HSCT (haplo-HSCT). Here, we demonstrated that IFNγ-producing NK cells were expanded in haplo-HSCT patients with CMV reactivation. We then identified these expanded cells as a subset of CD56dim NK cells that expressed higher levels of both NKG2C and KIR, but lower level of NKG2A. Functionally, the subset of NK cells expressing NKG2C and self-KIR in patients with CMV reactivation accounted for IFNγ production in response to K562 cells. However, these phenomena were not observed in patients without CMV reactivation. We therefore characterized a subset of NK cells with the CD56dim, NKG2C+, and self-KIR+ phenotype that expanded and were responsible for IFNγ production during CMV infection after haplo-HSCT. Together, these findings support a notion that CMV reactivation induces expansion of more mature NK cells with memory-like features, which contributes to long-term control of both CMV infection and leukemia relapse after haplo-HSCT.

The anti-tumor role of NK cells in vivo pre-activated and re-stimulated by interleukins in acute lymphoblastic leukemia

Although natural killer cells (NK cells) were traditionally classified as members of the innate immune system, NK cells have recently been found also to be an important player in the adaptive immune systems. In this context, in vitro activation of NK cells by cytokines leads to generation of NK cells with memory-like properties characterized by increased interferon-γ (IFNγ) production. However, it remains to be defined whether these memory-like NK cells exist in vivo after cytokine activation. Furthermore, it is also unclear whether such memory-like NK cells induced in vivo by cytokines could have effective anti-leukemia response. To address these issues, we used an in vivo pre-activation and re-stimulation system that was able to produce NK cells with increased IFNγ secretion. It was found that after in vivo pre-activation and re-stimulation with interleukins (ILs), NK cells retained a state to produce increased amount of IFNγ. Of note, whereas this intrinsic capacity of enhanced IFNγ production after in vivo IL pre-activation and re-stimulation could be transferred to the next generation of NK cells and was associated with prolonged survival of the mice with acute lymphoid leukemia. Moreover, the anti-leukemia activity of these memory-like NK cells was associated with IFNγ production and up-regulation of NK cells activation receptor-NK Group 2 member D (NKG2D). Together, these findings argue strongly that in vivo IL pre-activation and re-stimulation is capable to induce memory-like NK cells as observed previously in vitro, which are effective against acute lymphoblastic leukemia, likely via NKG2D-dependent IFNγ production, in intact animals.

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 [including both complex karyotypes (CKs) and monosomal karyotypes (MKs)]. Different age distributions were observed in these karyotype groups. The frequency of the normal karyotype increased with age from 6.67 to 58.33% (χ2 = 20.68, p = 0.001), whereas that of the balanced karyotypes decreased with age from 73.33 to 11.11% (χ2 = 48.22, p < 0.001). Furthermore, the occurrence of the unbalanced karyotypes and CKs also increased with age (p < 0.05). No age-specific distributions were observed for the MK subgroups and the different molecular markers (NPM1, FLT3-ITD and c-kit). The cytogenetic subtypes were also related to the French-American-British classification, peripheral blood white cell count and molecular markers. In conclusion, the different age profiles of the cytogenetic subtypes may implicate different mechanisms in the pathogenesis of AML, which may be beneficial for etiological research and the prevention of AML.

Immune dysregulation in myelodysplastic syndrome: Clinical features, pathogenesis and therapeutic strategies

Myelodysplastic syndrome (MDS) is a heterogeneous hematological malignancy, characterized by cytopenia and accompanied by a risk of transformation into acute myeloid leukemia (AML). Epidemiological studies for decades have shown association between autoimmune diseases (AIDs) and MDS. Specifically, patients with antecedent AIDs tends to have an increased risk of developing MDS, and these patients display different clinical characteristics and outcomes. Importantly, immune dysregulation has been the common driving force between MDS and AIDs pathogenesis. Both innate and adaptive immune systems are overly active in the hematopoietic niche of MDS. It has been observed that in addition to many cytokines secreted in the bone marrow (BM) microenvironment, almost all types of immune cells and their downstream signaling pathways participate in MDS pathogenesis and evolution. Currently, growth factor therapy and hypomethylating agents (HMAs), along with supportive care, are the mainstay for MDS treatment. As information about the contribution of immune system has started emerging in different subtypes of MDS, we need to highlight the value of immunomodulatory therapies. Immune activation seems to participate specifically in the development of lower-risk MDS, and therefore, use of immunosuppressive therapies would be an ideal treatment option for this type. However, in high-risk MDS, escape from immune surveillance appears to contribute to its progression, and thus, several immune-activating treatment options, including immune checkpoint inhibitors and vaccines, are being considered. HMAs have been approved for use in treating high-risk MDS for many years based on their cytotoxicity, but since they also display an epigenetic-immunomodulatory role, they can be an option for lower-risk MDS. Thus, in this review, we discuss the immune dysregulation in MDS, including its clinical features, pathogenic mechanism and immunomodulatory therapeutic options.

The Surface Molecular Signature of Leukemic Cells Is Associated with NPM1 Mutations and FLT3-ITD in Patients with de novo Acute Myeloid Leukemia

Certain molecular mutations are associated with signs of cell morphology and differentiation in acute myeloid leukemia (AML). However, only limited data are available for the detailed analysis of such correlations. In this study, AML patients were classified into 4 subsets according to CD34, HLA-DR and CD11c expression levels. Significantly low CD34 antigen expression was observed in nucleophosmin (NPM1)-mutated patients and in those with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD). No correlations were observed among NPM1 mutations, FLT3-ITD and monocytic morphology in patients without CD34 expression. Both NPM1 mutations and FLT3-ITD were absent in cluster IIb patients (CD34+CD11c-). The associations among NPM1 mutations, FLT3-ITD and the surface molecular signature of leukemic cells may offer beneficial information about the pathogenesis of AML.

Analysis of the efficacy of lenalidomide in patients with intermediate‑1 risk myelodysplastic syndrome without 5q deletion

The aim of this study was to evaluate the efficacy and adverse effects of lenalidomide in the treatment of intermediate-1 risk non-5q deletion [non-del (5q)] myelodysplastic syndrome (MDS). A total of 30 patients with MDS were classified through G-banding chromosome karyotype analysis and fluorescence in situ hybridization (FISH). According to the International Prognostic Scoring System scores, among the 30 patients, 23 and seven cases had scores of 0.5 and 1.0, respectively. Lenalidomide (Revlimid®), 10 mg/day) was administered for 21 days every 28 days. All 30 cases were treated with lenalidomide for at least three cycles, including 20 cases with four cycles. The patients did not require erythropoietin, cyclosporine or iron chelation treatments. Statistical analysis was performed using SPSS statistical software version 13.0, and comparisons among groups were conducted using a t-test. The efficacy of lenalidomide was demonstrated in patients with intermediate-1 risk non-del (5q) MDS. Peripheral blood cell counts were improved following treatment, and absolute neutrophil, haemoglobin and platelet counts increased following 2–4 cycles of treatment. All patients became stable having undergone three cycles of treatment; however, 17 patients with chromosomal abnormalities had no cytogenetic response to the treatment, as confirmed through the FISH test. Patients with intermediate-1 risk non-del (5q) MDS treated with lenalidomide did not achieve complete haematological remission, although they demonstrated haematological improvement.

Mutational spectrum of acute myeloid leukemia patients with double CEBPA mutations based on next-generation sequencing and its prognostic significance

The aim of this study was to profile the spectrum of genetic mutations in acute myeloid leukemia (AML) patients co-occurring with CEBPA double mutation (CEBPAdm). Between January 1, 2012, and June 30, 2017, 553 consecutive patients with de novo AML were screened for CEBPA mutations. Out of these, 81 patients classified as CEBPAdm were analyzed further by a sensitive next-generation sequencing assay for mutations in 112 candidate genes. Within the CEBPA gene itself, we found 164 mutations. The most common mutated sites were c.936_937insGAG (n = 11/164, 6.71%) and c.939_940insAAG (n = 11/164, 6.71%), followed by c.68dupC (n = 10/164, 6.10%). The most common co-occurring mutations were found in the CSF3R (n = 16/81, 19.75%), WT1 (n = 15/81, 18.52%), and GATA2 (n = 13/81, 16.05%) genes. Patients with CSF3R mutations had an inferior four-year relapse-free survival (RFS) than those with the wild-type gene (15.3% versus 46.8%, respectively; P = 0.021). Patients with WT1 mutations had an inferior five-year RFS compared with those without such mutations (0% versus 26.6%, respectively, P = 0.003). However, GATA2, CSF3R, WT1 mutations had no significant influence on the overall survival. There were some differences in the location of mutational hotspots within the CEBPA gene, as well as hotspots of other co-occurring genetic mutations, between AML patients from Chinese and Caucasian populations. Some co-occurring mutations may be potential candidates for refining the prognoses of AML patients with CEBPAdm in the Chinese population.

Long noncoding RNAs and their epigenetic function in hematological diseases

Recent discoveries demonstrate the importance of long noncoding RNA (lncRNA) in the regulation of multiple major processes impacting development, differentiation, and metastasis of hematological diseases through epigenetic mechanisms. In contrast to genetic changes, epigenetic modification does not modify genes but is frequently reversible, thus providing opportunities for targeted treatment using specific inhibitors. In this review, we will summarize the function and epigenetic mechanism of lncRNA in malignant hematologic diseases.