KIAA1524: A novel MLL translocation partner in acute myeloid leukemia

The Mixed Lineage Leukemia gene on chromosome 11q23 is a frequent site of recurrent translocations in acute leukemias. Its promiscuous character is reflected by the more than 60 different translocation partners described in literature. Prompted by karyotype and atypical FISH results, we identified a new translocation partner in infant acute myeloid leukemia, KIAA1524 on 3q13.13, also known as ‘Cancerous Inhibitor of Protein phosphatase 2A (CIP2A)’. This gene was recently identified as a proto-oncogene stabilizing MYC protein in gastric carcinoma. KIAA1524 has never been related to hematologic malignancies before, and the current AML case is the first case in which an MLL-KIAA1524 fusion was described.     

Expression of HOXB genes is significantly different in acute myeloid leukemia with a partial tandem duplication of MLL vs. a MLL translocation: a cross-laboratory study

In acute myeloid leukemia (AML), the mixed lineage leukemia (MLL) gene may be rearranged to generate a partial tandem duplication (PTD), or fused to partner genes through a chromosomal translocation (tMLL). In this study, we first explored the differentially expressed genes between MLL-PTD and tMLL using gene expression profiling of our cohort (15 MLL-PTD and 10 tMLL) and one published data set. The top 250 probes were chosen from each set, resulting in 29 common probes (21 unique genes) to both sets. The selected genes include four HOXB genes, HOXB2, B3, B5, and B6. The expression values of these HOXB genes significantly differ between MLL-PTD and tMLL cases. Clustering and classification analyses were thoroughly conducted to support our gene selection results. Second, as MLL-PTD, FLT3-ITD, and NPM1 mutations are identified in AML with normal karyotypes, we briefly studied their impact on the HOXB genes. Another contribution of this study is to demonstrate that using public data from other studies enriches samples for analysis and yields more conclusive results.     

Identification of precursors of leukemic dendritic cells differentiated from patients with acute myeloid leukemia.

Dendritic cells (DC) can facilitate immune responses that might help in the induction of effective antitumor T cell responses. We reported previously that leukemic blasts from selected patients with acute myeloid leukemia (AML) were able to differentiate in vitro into cells with mature DC features. However, despite the use of a wide variety of cytokine combinations, leukemic DC could not be obtained from all AML patients. In this study, we investigated in a wide range of AML patients (n = 30), the nature and functional characteristics of the blast compartment that can be induced to acquire DC features in vitro. Our results demonstrate that leukemic DC generated in the presence of GM-CSF, IL-4 and matured with CD40L, are composed of two major subsets: DC derived from CD14(+) leukemic cells and leukemic DC derived from in vivo expanded circulating blood myeloid DC (MDC). Leukemic DC of both subsets exhibited DC morphology, had a phenotype of mature DC, and could induce a potent proliferative response of naive CD4(+) T cells. Moreover, both subsets produced large amounts of IL-12p70 and leukemic CD14(+)-derived DC could induce a potent Th1 response. These results can be considered as a prerequisite before the design of vaccine immunotherapy protocols for the adjuvant treatment of AML patients.     

Variations in MLL amplification in a patient with acute myeloid leukemia

In a 66 years old female patient with acute myeloblastic leukemia (AML) complex chromosomal rearrangements involving 11q23 were diagnosed by G-banding and confirmed by different fluorescence in situ hybridization (FISH) techniques. The amplification of MLL gene differed in various sidelines as shown by locus specific probes for 11q23 and 11q13. Complex karyotype rearrangements involving deletions del(5)(q31) and del(7)(q31) were verified by multicolor fluorescence in situ hybridization (mFISH).     

Abundant expression of fibronectin is a major feature of leukemic dendritic cells differentiated from patients with acute myeloid leukemia.

Dendritic cells (DCs) are the most potent antigen-presenting cells responsible for the initiation of primary immune responses, playing a key role in eliciting effective antitumor immune responses. We reported previously that leukemic blasts from selected patients with acute myeloid leukemia (AML) were able to differentiate in vitro into cells with DC features. In order to identify genes differentially expressed in leukemia-derived DCs (AML-DCs), a polymerase chain reaction (PCR)-based subtraction approach was applied using cDNA from AML-DCs and monocyte-derived DCs from healthy donors as competitors. In the 548 sequences analyzed, 80% corresponded to fibronectin (FN) gene fragments. Overexpression of FN in AML-DCs was demonstrated both by semiquantitative PCR analysis and by immunostaining. In addition, we could show that FN was secreted by AML-DCs. Indeed, FN overexpression was already detectable in AML blasts of M4 and M5 subtype, and was significantly induced during DC differentiation after culture. Although the molecular events leading to overexpression of FN and the in vivo relevance of this phenomenon remain to be resolved, leukemic DCs appear to have specific patterns of differentiation, warranting stringent biological and cellular monitoring for the development and testing of leukemic DC-based immunotherapeutic strategies.     

Chromosome abnormalities and MLL rearrangements in acute myeloid leukemia of infants.

Of 29 infants with acute myeloid leukemia (AML), 14 (48%) had various 11q23 translocations. MLL rearrangements were examined in 21 of the 29 patients, and 11 (52%) showed the rearrangements. 11q23 translocations and/or MLL rearrangements were found in 17 (58%) of the 29 patients. While all but one of the 17 patients with 11q23/MLL rearrangements had M4 or M5 type of the FAB classification, the 12 patients without such rearrangements had various FAB types, including M2, M4, M4EO, M6 and M7. Of the 12 patients with other chromosome abnormalities or normal karyotypes, two had inv(16) ort(16;16), one had t(1;22)(p13;q13), and two had a novel translocation, t(7;12)(q32;p13). The breakpoint on 12p of the t(7;12) was assigned to intron 1 or the region just upstream of exon 1 of the TEL/ETV6 gene by fluorescence in situ hybridization. The event-free survival at 5 years for the 17 patients with 11q23/MLL rearrangements was 42.2%, and that for the 12 patients without such rearrangements was 31.3% (P = 0.5544). 11q231MLL rearrangements have been frequently reported and a poor prognosis in infant acute lymphoblastic leukemia implied. Our study showed that while 11q23/MLL rearrangements were also common in infant AML, AML infants with such rearrangements had a clinical outcome similar to that of AML infants without such rearrangements.     

Telomerase activity is prognostic in pediatric patients with acute myeloid leukemia: comparison with adult acute myeloid leukemia

BACKGROUND: Significantly elevated telomerase activity (TA) has been found in samples from patients with almost all malignant hematologic diseases. The impact of elevated TA on the course of pediatric patients with acute myeloid leukemia (P-AML) is unknown. METHODS: Using a modified polymerase chain reaction-based, telomeric repeat-amplification protocol assay, the authors measured TA in bone marrow samples from 40 patients with P-AML and, for comparison, in 65 adult patients with AML (A-AML), excluding patients with French-American-British M3 disease. The results were correlated with patient characteristics and survival. RESULTS: TA in patients with P-AML was significantly lower compared with TA in patients with A-AML (P = 0.005). Patients who had P-AML with low TA had a projected 5-year survival rate of 88%, whereas patients who had P-AML with high TA had a projected 5-year survival rate of 43% (P = 0.009). Conversely, patients who had A-AML with very high TA (upper quartile) had significantly longer survival compared with patients who had A-AML with lower TA (P = 0.03). There was no correlation between complete remission rate or disease free survival and TA in P-AML or A-AML. In the A-AML group, when patients were separated by cytogenetic findings (poor prognosis vs. others), it was found that TA was significantly lower in patients with a poor prognosis, but the prognostic value of TA was not independent of cytogenetic status. CONCLUSIONS: The current results suggest, that for patients with P-AML, bone marrow TA is a highly significant prognostic factor.     

由急性早幼粒细胞白血病转化的原始粒细胞白血病部分分化型一例并文献复习

目的 提高对继发性急性白血病的认识.方法 报道1例急性早幼粒细胞白血病(APL)转化为原始粒细胞白血病部分分化型[急性髓系白血病(AML)-M2]患者的诊断及治疗过程,并进行文献复习.结果 患者起病时,表现为咽痛、乏力,血小板减少.细胞形态学、免疫学、细胞遗传学和分子生物学(MICM)分型诊断为APL,PML-RARα融合基因阳性.给予维甲酸、亚砷酸双诱导并加用米托蒽醌诱导治疗后,达完全缓解.后以IA、HA、MA方案巩固3个疗程;以维甲酸、亚砷酸维持治疗.完全缓解持续4年4个月.后出现骨髓原始幼稚粒细胞增加,经MICM分型诊断为AML-M2,PML-RARα融合基因阴性,WT1阳性.予地西他滨+HAG方案化疗后再次完全缓解,地西他滨+HAG方案巩固4个疗程,后以地西他滨+CAG方案间断维持治疗,患者持续缓解中.结论 继发性白血病多属于治疗相关性白血病,染色体异位导致癌基因直接形成、 遗传不稳定或之前存在的难治性造血干细胞克隆的选择可能是其发病机制.     

Minimally differentiated acute myeloid leukemia: a morphologic, cytochemical and ultrastructural study.

Seven of 368 cases of acute myeloid leukemia (AML) could not be subclassified by routine morphologic, cytochemical and immunologic analyses during the period January 1989 to December 1990. Further investigations including ultrastructural examination, anti-myeloperoxidase and myeloid specific antigen analysis were carried out in all these patients and they were classified as AML-MO, as per the FAB criteria. Morphologically these blasts resembled ALL-L2/AML-M1. Cytochemically they were negative for Sudan black, myeloperoxidase, periodic acid-Schiff, and non-specific esterase. On initial immunophenotypic analysis, they could not be classified into B, T or myeloid lineages. Further investigations revealed CD13 and CD33 positivity in 4 of 6 patients. Anti-myeloperoxidase was positive in 6 of 6 patients and ultrastructural examination revealed myeloperoxidase-positive blasts in 6 of 7 cases. Cytogenetic analysis done in one patient revealed 60% abnormal metaphases. Six of 7 cases were treated with aggressive chemotherapy. One patient achieved complete remission but relapsed after 6 months, whereas others were resistant to treatment. Hence we conclude that an aggressive investigative and therapeutic approach is required to identify and treat AML-MO.     

Acute myeloid leukemia with hypergranular cytoplasm: a differential diagnosis of acute promyelocytic leukemia

We report here the case of a woman with acute myeloid leukemia with some blast cells exhibiting acute promyelocytic leukemia (APL)-like hypergranular cytoplasm. The cytologic and cytochemical aspects as well as the mature myeloid phenotype and hemostasis disorders were consistent with the diagnosis of APL. However, no t(15;17), or RARalpha gene, MLL gene or PML gene rearrangement was observed, or any other cytogenetic clonal abnormality. Coexpression on blast cells of CD33 and CD56 without CD34, CD16 or HLA-DR, suggested a myeloid/natural killer cell acute leukemia.     

Stratification of pediatric acute myeloid leukemia through cancer cell gene-expression profiling

Treatment of children's acute lymphoblastic leukemia has been at the forefront of conventional chemotherapy development. Despite outstanding results in long-term survival of acute lymphoblastic leukemia, development of therapies for acute myeloid leukemia (AML) have lagged behind. AML in children demonstrate similar long-term survival compared with adults 18-65 years of age: 40-50% overall long-term survival. AML is a heterogeneous disease in both adults and children, but the presence of recurrent chromosome translocations and mutations in children are lower than in adult AML. In particular, patients without chromosome aberrancies have been examined for stratification through examination of gene expression. The paper from Baglobind and coauthors proposes a useful prognostication by gene-expression analysis of 75 gene pairs in 40% of patient cases, accurately discriminating mixed lineage leukemia (MLL) gene rearrangement, t(8;21)(q22;q22), inv(16)(p13q22), t(15;17)(q21;q22) and t(7;12)(q36;p13)-positive AML. Gene-expression analysis of AML has provided an important research tool for uncovering information about AML biology that can be used for the development of novel therapies.     

Stratification of pediatric acute myeloid leukemia through cancer cell gene-expression profiling

Evaluation of: Balgobind BV, Marry M, van den Heuvel-Eibrink MM et al. Evaluation of gene expression signatures predictive for cytogenetic and molecular subtypes of pediatric acute myeloid leukemia. Haematologica 96(2), 221–230 (2010).

Treatment of children^’s acute lymphoblastic leukemia has been at the forefront of conventional chemotherapy development. Despite outstanding results in long-term survival of acute lymphoblastic leukemia, development of therapies for acute myeloid leukemia (AML) have lagged behind. AML in children demonstrate similar long-term survival compared with adults 18–65 years of age: 40–50% overall long-term survival. AML is a heterogeneous disease in both adults and children, but the presence of recurrent chromosome translocations and mutations in children are lower than in adult AML. In particular, patients without chromosome aberrancies have been examined for stratification through examination of gene expression. The paper from Baglobind and coauthors proposes a useful prognostication by gene-expression analysis of 75 gene pairs in 40% of patient cases, accurately discriminating mixed lineage leukemia (MLL) gene rearrangement, t(8;21)(q22;q22), inv(16)(p13q22), t(15;17)(q21;q22) and t(7;12)(q36;p13)-positive AML. Gene-expression analysis of AML has provided an important research tool for uncovering information about AML biology that can be used for the development of novel therapies.     

BCR translocation to derivative chromosome 2: a new case of chronic myeloid leukemia with a complex variant translocation and Philadelphia chromosome

The well-known typical fusion gene BCR/ABL is observed in connection with a complex translocation event in 5-8% of cases of chronic myeloid leukemia (CML). The present study described an exceptional CML case with complex chromosomal aberrations not previously observed. Aberrations included a translocated BCR to the derivative chromosome 2 [der(2)] that also involved a four-chromosome translocation, implying chromosomal regions 1p32 and 2q21, besides 9q34 and 22q11.2, which were characterized by molecular cytogenetics.     

治疗急性髓系白血病的树突状细胞疫苗的研究进展

摘 要 本文综述了免疫治疗急性髓系白血病（acute myeloid leukemia, AML）的树突状细胞（dendritic cells, DC）疫苗的近期研究进展，主要涉及各种类型的白血病肿瘤抗原的确认与制备，包括AML特异融合蛋白及相关多肽、癌症睾丸抗原、酸洗脱多肽、白血病细胞冻融抗原/凋亡细胞、AMLDC融合细胞、白血病细胞来源的DC等；DC的制备与特性以及优化方法；临床试验研究的初步结果等，还对今后的研究方向进行了分析和展望。