Molecular cytogenetic findings of acute leukemia included in the Brazilian Collaborative Study Group of Infant acute leukemia

BACKGROUND: Chromosome abnormalities often occur prenatally in childhood leukemia, characterizing an early event in leukemogenesis. The majority of the abnormalities occurring in infants involve the MLL gene on chromosome band 11q23. We describe the molecular cytogenetic findings of 207 infant acute leukemia (IAL) cases included in the Brazilian Collaborative Study Group of Infant acute leukemia. PROCEDURE: The diagnosis of Acute Lymphoblastic leukemia (ALL) or acute myeloblastic leukemia (AML) was made according to morphology and immunophenotyping classification, followed by conventional karyotyping. Samples were then screened using RT-PCR for the presence of specific chromosome translocations. FISH assay for MLL rearrangements was performed only in cases with negative or inconclusive cytogenetic or PCR results. RESULTS: The characteristics of children with IAL were as follows: 115 boys and 92 girls, age range 0-23 months, mean age 12 months, 145 ALL, and 62 AML. A statistically significant association was observed between pro-B ALL cases and MLL+ve (P=0.0001) cases and the age group 0-3 months with MLL+ve (P=0.008) cases. Two rare cases of pro-T ALL with MLL+ve were found. Other than MLL rearrangements, various other molecular aberrations were detected including TEL/AML1+ve (n=9), E2A/PBX1+ve (n=4), PML/RARA+ve (n=4), and AML1/ETO+ve (n=2). Cytogenetic analysis revealed hyperdiploidy (n=6), del(7) in two cases and del(11)(q23) in seven cases. CONCLUSIONS: Our results show that not only MLL rearrangements, but also other molecular abnormalities occur before birth and may contribute to leukemogenesis.     

应用实时定量PCR检测儿童急性髓系白血病AML1-ETO融合基因

目的应用实时定量聚合酶链式反应方法,分析儿童急性髓系白血病中AML1ETO融合基因的表达水平,探讨AML1ETO表达水平的变化规律。方法采用实时定量PCR方法,以AML1ETO融合基因为靶分子,定量检测了28例急性髓系白血病患儿初诊时融合基因的表达量,分析了表达量与初诊临床特征的相关性,并对17例患者进行微小残留病定量分析。结果患者AML1ETO融合基因的表达范围在未治疗前达到17094～187800拷贝/106GAPDH拷贝;长期缓解的患者表达量降到0～46拷贝/106GAPDH拷贝;复发患者融合基因表达范围为62633.8～246000拷贝/106GAPDH拷贝。初诊时患者AML1ETO融合基因的表达量与临床特征无相关性(P均>0.05)。结论应用实时定量PCR技术对AML1ETO的定量检测是判断和追踪该类白血病疗效的有力指标,可以较好地反映患者的微小残留病的动态变化。     

Equal frequency of TEL/AML1 rearrangements in children with acute lymphoblastic leukemia with and without Down syndrome

Constitutional trisomy 21 is the most prominent predisposing factor to childhood leukemia, whereas the t(12;21)(p13;q22) with its molecular genetic counterpart, the TEL/AML1 fusion gene, is the most common acquired chromosomal rearrangement in childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1⁺ BCP ALL is extremely low in patients with Down syndrome (DS). To further investigate this issue in a population-based fashion, the authors retrospectively assessed the number of DS patients with a TEL/AML1⁺ ALL in two consecutive Austrian ALL multicenter trials. Accordingly, they were able to analyze 8 of 10 individuals with DS and a BCP ALL, two of whom who suffered from a TEL/AML1⁺ leukemia. Based on this observation they concluded that individuals with BCP leukemia and a constitutional trisomy 21 may have similar likelihood to have a TEL/AML1 rearrangement as BCP ALL patients without this specific predisposing factor.     

Upfront use of gemtuzumab ozogamicin in young children with CD33‐positive AML

Gemtuzumab ozogamicin (GO) is a humanized anti‐CD33 antibody used for treating patients with CD33+ acute myeloid leukemia (AML). We report three young children (two infants and one toddler) with AML treated with GO 9 mg/m². Two received two doses at diagnosis alone with conventional chemotherapy and one received one dose after relapse. GO was well tolerated and all three achieved remission. All were transplanted: one relapsed after 5 months and died of disease, one died a toxic death in remission due to pulmonary fibrosis, and one survived (41 months from diagnosis). In conclusion, GO was well tolerated in these young patients with evidence for efficacy. Pediatr Blood Cancer 2010;55:183–185. © 2010 Wiley‐Liss, Inc.     

EQUAL FREQUENCY OF TEL/AML1 ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDREN WITH AND WITHOUT DOWN SYNDROME

Constitutional trisomy 21 is the most prominent predisposing factor to childhood leukemia, whereas the t(12;21)(p13;q22) with its molecular genetic counterpart, the TEL/AML1 fusion gene, is the most common acquired chromosomal rearrangement in childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1+ BCP ALL is extremely low in patients with Down syndrome (DS). To further investigate this issue in a population-based fashion, the authors retrospectively assessed the number of DS patients with a TEL/AML1+ ALL in two consecutive Austrian ALL multicenter trials. Accordingly, they were able to analyze 8 of 10 individuals with DS and a BCP ALL, including 2 who suffered from a TEL/AML1+ leukemia. Based on this observation we concluded that individuals with a constitutional trisomy 21 may have the similar likelihood to develop a TEL/AML1+ leukemia as BCP ALL patients without this specific predisposing factor.     

治疗相关白血病1例报告

目的探讨急性淋巴细胞白血病患者长期化疗后发生治疗相关骨髓增生异常综合征白血病(t-MDS/AML)的临床特征及预后。方法观察一例儿童急性淋巴细胞白血病经化疗后演变为幼年慢性粒-单核细胞白血病(JMML)的临床演变过程及治疗结果并进行相关文献复习。结果1例急性淋巴细胞白血病患儿经3年正规化疗停药后3月,外周血白细胞进行性增高并出现原始粒、单核细胞。各项检查支持幼年慢性粒-单核细胞白血病诊断。根据2000年WHO造血组织和淋巴组织肿瘤分类方法,归于MDS/MPD一类疾病。患者迅速进展为AML-M4b,治疗无效死亡。结论t-MDS比原发性MDS病情进展更快,预后更差。t-AML临床预后不良,骨髓移植及大剂量化疗仅对部分患者有效。应进一步加强儿童ALL患者的合理用药,根据不同危险度分型,选取相应治疗强度化疗方案,以减少t-MDS/AML发生的可能。     

IDH1 mutated acute myeloid leukemia in a child with metaphyseal chondromatosis with D-2-hydroxyglutaric aciduria

Abstract

D-2-hydroxyglutaric aciduria (D-2-HGA) is a rare metabolic disorder characterized by developmental delay, hypotonia, and bi-allelic mutations in D-2-hydroxyglutarate dehydrogenase (D2HGDH) or a single gain-of-function mutation in isocitrate dehydrogenase 2 (IDH2). Metaphyseal chondromatosis with D-2-hydroxyglutaric aciduria (MC-HGA) is a type of D-2-HGA that has been previously reported in ten patients (OMIM 614875), three of whom had somatic mosaicism for R132 variants in isocitrate dehydrogenase 1 (IDH1). We describe a 3-year-old boy with MC-HGA who subsequently developed acute myeloid leukemia (AML) and was found to have an IDH1 R132C mutation in a leukemic bone marrow sample. Further testing revealed presence of somatic mosaicism for IDH1 R132C variant, suggesting an association of IDH1 in inducing myeloid leukemogenesis.     

Chemokine/chemokine receptor interactions in extramedullary leukaemia of the skin in childhood AML: Differential roles for CCR2, CCR5, CXCR4 and CXCR7

Chemokine receptor/ligand interactions orchestrate the migration of cells to peripheral tissues such as the skin. We analysed chemokine receptor expression by acute myeloid leukaemic (AML) cells present in peripheral blood (n = 7), bone marrow (n = 6), or skin (n = 11) obtained from 15 paediatric AML patients with skin involvement and in 10 AML patients without skin involvement. High percentages of circulating CCR2^pos AML cells were only detected in patients with extramedullary disease. Skin‐residing AML cells displayed a different set of receptors in situ, namely: CCR5, CXCR4, CXCR7 and CX3CR1. These results suggest the involvement of different chemokine/chemokine receptor interactions in homing and retention of AML blasts in the skin. Pediatr Blood Cancer. 2010;55:344–348. © 2010 Wiley–Liss, Inc.     

Myeloid lineage switch following chimeric antigen receptor T‐cell therapy in a patient with TCF3‐ZNF384 fusion‐positive B‐lymphoblastic leukemia

A pediatric patient diagnosed initially with B‐lymphoblastic leukemia (B‐ALL) relapsed with lineage switch to acute myeloid leukemia (AML) after chimeric antigen receptor T‐cell (CAR‐T) therapy and hematopoietic stem cell transplant. A TCF3‐ZNF384 fusion was identified at diagnosis, persisted through B‐ALL relapse, and was also present in the AML relapse cell population. ZNF384‐rearrangements define a molecular subtype of B‐ALL characterized by a pro‐B‐cell immunophenotype; furthermore, ZNF384‐rearrangements are prevalent in mixed‐phenotype acute leukemias. Lineage switch following CAR‐T therapy has been described in patients with KMT2A (mixed lineage leukemia) rearrangements, but not previously in any patient with ZNF384 fusion.     

AML1-ETO阳性的儿童急性髓系白血病疗效分析

目的探讨儿童急性髓系白血病m2型伴AML1-ETO阳性患儿的疗效及预后相关因素。方法2003年1月至2008年12月收住AML1-ETO阳性儿童m233例,并对患儿进行总结分析、随访。了解患儿临床特征,免疫分型,染色体核型治疗及疗效,生存情况及影响治疗的因素。结果33例AML1-ETO阳性儿童第一疗程诱导缓解率为63.5%,中位随访时间32个月,目前仍处于CR状态25例占75.5%,5例患儿骨髓复发,复发率为15.1%,高白细胞数,多脏器受累,免疫表型CD5＋6以及第一疗程诱导治疗未达缓解者预后不良,并伴有较低的生存率。结论儿童急性髓系白血病M2伴有AML1-ETO阳性患儿预后是好的。强烈化疗高剂量阿糖胞苷能帮助提高疗效。提高生存率。高白细胞计数,累及多脏器以及CD56标记阳性和初次诱导治疗的缓解不佳,影响总的生存率。