A Case of AML1/ETO Positive Child with Acute Myeloid Leukemia with Poor Prognosis

BACKGROUND

The aim was to improve the understanding of an AML1/ETO positive child with acute myeloid leukemia with poor prognosis.

METHODS

A case of AML1/ETO positive child with acute myeloid leukemia with poor prognosis was reported. The bone marrow cell morphology, multi-parameter flow cytometry, cytogenetic or molecular genetic test results were analyzed by reviewing relevant literature.

RESULTS

The patient was a young girl with clinical manifestations of respiratory tract infection. Bone marrow smears showed that myeloid primordial cells accounted for 13%, some granulocyte cell bodies are enlarged, visible pathological phenomena such as cytoplasmic vacuoles, binuclear grains, ring rods, and pseudo pelgerhuet malformations were seen (Figure 1). Flow cytometry: abnormal myeloid original cells (12.33%), expression of CD34 and HLA - DR, CD38, CD56, part of the expression of CD117, weak expression of CD13, CD33, MPO, CD19, cCD79a (Figure 2). Chromosome karyotype analysis showed that the chromosome karyotype of peripheral blood was 46, XX, t(8;21)(q22;q22). The quantitative detection result of AML1/ETO fusion gene was 42.15%, and mutations of NRAS, ASXL2, TP53 and TET2 genes were detected by second-generation sequencing. Combined with the above results, AML1/ETO positive with acute myeloid leukemia was diagnosed.

CONCLUSIONS

Cytogenetics or molecular genetics is the gold standard for identification of positive AML1/ETO fusion gene. Morphological heterogeneity of AML1/ETO positive AML cells is large, which limits the morphological diagnosis of bone marrow cells to a certain extent, and the comprehensive diagnostic efficiency is significantly better than that of morphology. Leukemia fusion gene AML1/ETO refers to the fusion of AML1 gene located on human chromosome 21q22 and ETO gene 8q22, which is the most common fusion gene in acute myeloid leukemia (AML). This paper reports a case of an AML1/ETO positive child with acute myeloid leukemia with poor prognosis admitted to our hospital and reviews relevant literature.

A comprehensive molecular characterization of the 8q22.2 region reveals the prognostic relevance of OSR2 mRNA in muscle invasive bladder cancer

Technological advances in molecular profiling have enabled the comprehensive identification of common regions of gene amplification on chromosomes (amplicons) in muscle invasive bladder cancer (MIBC). One such region is 8q22.2, which is largely unexplored in MIBC and could harbor genes with potential for outcome prediction or targeted therapy. To investigate the prognostic role of 8q22.2 and to compare different amplicon definitions, an in-silico analysis of 357 patients from The Cancer Genome Atlas, who underwent radical cystectomy for MIBC, was performed. Amplicons were generated using the GISTIC2.0 algorithm for copy number alterations (DNA_Amplicon) and z-score normalization for mRNA gene overexpression (RNA_Amplicon). Kaplan-Meier survival analysis, univariable, and multivariable Cox proportional hazard ratios were used to relate amplicons, genes, and clinical parameters to overall (OS) and disease-free survival (DFS). Analyses of the biological functions of 8q22.2 genes and genomic events in MIBC were performed to identify potential targets. Genes with prognostic significance from the in silico analysis were validated using RT-qPCR of MIBC tumor samples (n = 46). High 8q22.2 mRNA expression (RNA-AMP) was associated with lymph node metastases. Furthermore, 8q22.2 DNA and RNA amplified patients were more likely to show a luminal subtype (DNA_Amplicon_core: p = 0.029; RNA_Amplicon_core: p = 0.01). Overexpression of the 8q22.2 gene OSR2 predicted shortened DFS in univariable (HR [CI] 1.97 [1.2; 3.22]; p = 0.01) and multivariable in silico analysis (HR [CI] 1.91 [1.15; 3.16]; p = 0.01) and decreased OS (HR [CI] 6.25 [1.37; 28.38]; p = 0.0177) in RT-qPCR data analysis. Alterations in different levels of the 8q22.2 region are associated with manifestation of different clinical characteristics in MIBC. An in-depth comprehensive molecular characterization of genomic regions involved in cancer should include multiple genetic levels, such as DNA copy number alterations and mRNA gene expression, and could lead to a better molecular understanding. In this study, OSR2 is identified as a potential biomarker for survival prognosis.

RUNX1-ETO Depletion in t(8;21) AML Leads to C/EBPα- and AP-1-Mediated Alterations in Enhancer-Promoter Interaction

Acute myeloid leukemia (AML) is associated with mutations in transcriptional and epigenetic regulator genes impairing myeloid differentiation. The t(8;21)(q22;q22) translocation generates the RUNX1-ETO fusion protein, which interferes with the hematopoietic master regulator RUNX1. We previously showed that the maintenance of t(8;21) AML is dependent on RUNX1-ETO expression. Its depletion causes extensive changes in transcription factor binding, as well as gene expression, and initiates myeloid differentiation. However, how these processes are connected within a gene regulatory network is unclear. To address this question, we performed Promoter-Capture Hi-C assays, with or without RUNX1-ETO depletion and assigned interacting cis-regulatory elements to their respective genes. To construct a RUNX1-ETO-dependent gene regulatory network maintaining AML, we integrated cis-regulatory element interactions with gene expression and transcription factor binding data. This analysis shows that RUNX1-ETO participates in cis-regulatory element interactions. However, differential interactions following RUNX1-ETO depletion are driven by alterations in the binding of RUNX1-ETO-regulated transcription factors.

RNA Sequencing Analysis for the Identification of a PCM1/PDGFRB Fusion Gene Responsive to Imatinib

The platelet-derived growth factor receptor β (PDGFRB) gene translocations lead to a spectrum of chronic myeloid neoplasms, frequently associated with eosinophilia. Clinical heterogeneity is associated with a molecular one. Here, we report a novel case of a patient harboring a t(5;8)(q33;p22) translocation, resulting in the PCM1/PDGFRB fusion. Conventional cytogenetics and RNA sequencing were performed to identify the chromosomes and the genes involved in the rearrangement, respectively. This study shows that the combination of different strategies is pivotal to fine-tune the diagnosis and the clinical management of the patient. After 1 year of treatment with imatinib, the patient achieves hematological and molecular remission. We present an attractive strategy to identify novel and/or cryptic fusions, which will be relevant for clinicians dealing with the diagnosis of the patients with myelodysplastic syndrome/myeloproliferative diseases with atypical manifestations.

The Crohn's disease associated SNP rs6651252 impacts MYC gene expression in human colonic epithelial cells

Crohn’s disease (CD) is a debilitating inflammatory bowel disease (IBD) that arises from chronic inflammation in the gastrointestinal tract. Genome-wide association studies (GWAS) have identified over 200 single nucleotide polymorphisms (SNPs) that are associated with a predisposition for developing IBD. For the majority, the causal variant and target genes affected are unknown. Here, we investigated the CD-associated SNP rs6651252 that maps to a gene desert region on chromosome 8. We demonstrate that rs6651252 resides within a Wnt responsive DNA enhancer element (WRE) and that the disease associated allele augments binding of the TCF7L2 transcription factor to this region. Using CRISPR/Cas9 directed gene editing and epigenetic modulation, we find that the rs6651252 enhancer regulates expression of the c-MYC proto-oncogene (MYC). Furthermore, we found MYC transcript levels are elevated in patient-derived colonic segments harboring the disease-associated allele in comparison to those containing the ancestral allele. These results suggest that Wnt/MYC signaling contributes to CD pathogenesis and that patients harboring the disease-associated allele may benefit from therapies that target MYC or MYC-regulated genes.

Functional enhancers at the gene-poor 8q24 cancer-linked locus

Multiple discrete regions at 8q24 were recently shown to contain alleles that predispose to many cancers including prostate, breast, and colon. These regions are far from any annotated gene and their biological activities have been unknown. Here we profiled a 5-megabase chromatin segment encompassing all the risk regions for RNA expression, histone modifications, and locations occupied by RNA polymerase II and androgen receptor (AR). This led to the identification of several transcriptional enhancers, which were verified using reporter assays. Two enhancers in one risk region were occupied by AR and responded to androgen treatment; one contained a single nucleotide polymorphism (rs11986220) that resides within a FoxA1 binding site, with the prostate cancer risk allele facilitating both stronger FoxA1 binding and stronger androgen responsiveness. The study reported here exemplifies an approach that may be applied to any risk-associated allele in non-protein coding regions as it emerges from genome-wide association studies to better understand the genetic predisposition of complex diseases.

Genome-wide scans of inherited genetic variation in the normal population have recently identified many sites (loci) associated with the predisposition to complex diseases such as cancer. Some of these cancer-associated loci, however, are devoid of genes (situated in so-called “gene deserts”) and the mechanism(s) of the association are not readily apparent. In the work reported here, we show that loci associated with several cancers in a gene desert found at chromosomal area 8q24 have embedded regulatory sequences affecting gene expression as enhancers, and in one case this activity is modulated by genetic variation. The results provide insight into the mechanism(s) governing genetic cancer risk.

Acute myeloid leukemia with the 8q22;21q22 translocation: secondary mutational events and alternative t(8;21) transcripts

Nonrandom and somatically acquired chromosomal translocations can be identified in nearly 50% of human acute myeloid leukemias. One common chromosomal translocation in this disease is the 8q22;21q22 translocation. It involves the AML1 (RUNX1) gene on chromosome 21 and the ETO (MTG8, RUNX1T1) gene on chromosome 8 generating the AML1-ETO fusion proteins. In this review, we survey recent advances made involving secondary mutational events and alternative t(8;21) transcripts in relation to understanding AML1-ETO leukemogenesis.

Concurrent transcriptional deregulation of AML1/RUNX1 and GATA factors by the AML1-TRPS1 chimeric gene in t(8;21)(q24;q22) acute myeloid leukemia

The Runt domain transcription factor AML1/RUNX1 is essential for the generation of hematopoietic stem cells and is the most frequent target of chromosomal translocations associated with leukemia. Here, we present a new AML1 translocation found in a patient with acute myeloid leukemia M4 with t(8;21)(q24;q22) at the time of relapse. This translocation generated an in-frame chimeric gene consisting of the N-terminal portion of AML1, retaining the Runt domain, fused to the entire length of TRPS1 on the C-terminus. TRPS1 encodes a putative multitype zinc finger (ZF) protein containing 9 C2H2 type ZFs and 1 GATA type ZF. AML1-TRPS1 stimulated proliferation of hematopoietic colony-forming cells and repressed the transcriptional activity of AML1 and GATA-1 by 2 different mechanisms: competition at their cognate DNA-binding sites and physical sequestrations of AML1 and GATA-1, suggesting that simultaneous deregulation of AML1 and GATA factors constitutes a basis for leukemogenesis.

Low-frequency magnetic field effect on cytoskeleton and chromatin

The effect of magnetic fields on the living systems is studied in vivo or in vitro in very broad spectrum of organisms, cells and tissues. The mechanism of their acting is not known until now. We studied low-frequency magnetic field effect on cytoskeleton and on the structure of chromatin in human cells. We used cell line of small lung carcinoma (A549) and the effects of magnetic field on cytoskeleton and higher-order chromatin structure were analyzed 96 h of magnetic field exposure. Magnetic field generated by the cylindrical soil was homogenous and the cells were cultivated at 37 degrees C in humidified atmosphere containing 5% CO(2). Magnetic field induction was B(m)=2 mT and the net frequency f=50 Hz. In such affected and control cells the F-actin was estimated using FITC-conjugated Phalloidin and mitochondria were studied using MitoTracker (Molecular Probes). Images of cytoskeleton and genetic loci were acquired using confocal microscopy and analysis was performed by FISH 2.0 software. Slight morphological changes of F-actin filaments and mitochondria were observed in affected cells and nuclear condensation was found. These effects could be related to the process of cell death apoptosis probably induced by magnetic field. The studies aimed at centromeric heterochromatin (9cen) did not show statistically significant changes. Therefore, we suggest that magnetic field has no influence on higher order chromatin structure but certain changes could be observed on the level of cytoskeleton. However, these statements need a thorough verification. Our preliminary experiments will be extended and the effect of magnetic field on another structures of cytoskeleton and cell nuclei will be further studied.

A leukemia fusion protein attenuates the spindle checkpoint and promotes aneuploidy

The 8;21 chromosomal translocation occurs in 15% to 40% of patients with the FAB M2 subtype of acute myeloid leukemia (AML). This chromosomal abnormality fuses part of the AML1/RUNX1 gene to the ETO/MTG8 gene and generates the AML1-ETO protein. We previously identified a C-terminal truncated AML1-ETO protein (AEtr) in a mouse leukemia model. AEtr is almost identical to the AML1-ETO exon 9a isoform expressed in leukemia patients. Here, we describe a novel function of AEtr in the development of aneuploidy through spindle checkpoint attenuation. AEtr cells had a reduced mitotic index following nocodazole treatment, suggesting a failure in a subset of cells to arrest in mitosis with a functional spindle checkpoint. Additionally, primary leukemia cells and cell lines expressing AEtr were aneuploid. Moreover, AEtr cells had reduced levels of several spindle checkpoint proteins including BubR1 and securin following treatment with the spindle poison nocodazole. These results suggest that inactivation of the spindle checkpoint may contribute to the development of aneuploidy described in t(8;21) leukemia patients.

Distinct nuclear arrangement of active and inactive c-myc genes in control and differentiated colon carcinoma cells

Using sequential RNA-DNA fluorescence in situ hybridization, the nuclear arrangement of both the active and inactive c-myc gene as well as its transcription was investigated in colon cancer HT-29 cells induced to differentiate into enterocytes. Cytogenetic studies revealed the presence of two chromosomes 8 in HT-29 cells, of which the one containing c-myc gene amplicons was substantially larger and easily distinguished from the normal chromosome. This observation enabled detection of both activity and nuclear localization of c-myc genes in single cells and in individual chromosome territories. Similar transcriptional activity of the c-myc gene was observed in both the normal and derivative chromosome 8 territories showing no influence of the amplification on the c-myc gene expression. Our experiments demonstrate strikingly specific nuclear and territorial arrangements of active genes as compared with inactive ones: on the periphery of their territories facing to the very central region of the cell nucleus. Nuclear arrangement of c-myc genes and transcripts was conserved during cell differentiation and, therefore, independent of the level of differentiation-specific c-myc gene expression. However, after the induction of differentiation, a more internal territorial location was found for the single copy c-myc gene of normal chromosome 8, while amplicons conserved their territorial topography.

Expression of the myeloperoxidase gene in AC133 positive leukemia cells relates to the prognosis of acute myeloid leukemia

We previously reported that the percentage of myeloperoxidase (MPO) positive blasts had a prognostic impact on survival of patients with acute myeloid leukemia (AML). To extend this observation, we quantitatively measured the level of the MPO gene in AC133 positive leukemia cells that would contain a putative AML stem/progenitor compartment. AML cases were divided into the MPO gene high (MPOg-H) and MPO gene low (MPOg-L) groups. Only patients belonging to the MPOg-H group had a favorable chromosomal translocation, t(8;21), and having no morphological dysplasia that was associated with MPOg-L. The difference in the survival of MPOg-H and MPOg-L was statistically meaningful, demonstrating the possible prognostic impact of the expression of MPO gene in AC133 positive leukemia cells.

Comprehensive Profiling of 8p11-12 Amplification in Breast Cancer

In human carcinomas, especially breast cancer, chromosome arm 8p is frequently involved in complex chromosomal rearrangements that combine amplification at 8p11-12, break in the 8p12-21 region, and loss of 8p21-ter. Several studies have identified putative oncogenes in the 8p11-12 amplicon. However, discrepancies and the lack of knowledge on the structure of this amplification lead us to think that the actual identity of the oncogenes is not definitively established. We present here a comprehensive study combining genomic, expression, and chromosome break analyses of the 8p11-12 region in breast cell lines and primary breast tumors. We show the existence of four amplicons at 8p11-12 using array comparative genomic hybridization. Gene expression analysis of 123 samples using DNA microarrays identified 14 genes significantly overexpressed in relation to amplification. Using fluorescence in situ hybridization analysis on tissue microarrays, we show the existence of a cluster of breakpoints spanning a region just telomeric to and associated with the amplification. Finally, we show that 8p11-12 amplification has a pejorative effect on survival in breast cancer.

Nuclear topography of the c-myc gene in human leukemic cells

The c-myc gene plays an essential role in the regulation of the cell cycle and differentiation. Therefore, changes of the c-myc positioning during differentiation are of great interest. As a model system of cell differentiation, the HL-60 and U-937 human leukemic cell lines were used in our experiments. These cells can be induced to differentiation into granulocytes that represent one of the pathways of blood cell maturation. In this study, changes of the topographic characteristics of the c-myc gene (8q24), centromeric region of chromosome 8 and chromosome 8 domain during differentiation of HL-60 and U-937 cells were detected using fluorescence in-situ hybridisation (FISH). FISH techniques and fluorescence microscopy combined with image acquisition and analysis (high-resolution cytometry) were used in order to detect the topographic features of nuclear chromatin. Increased centre of nucleus-to-gene and gene-to-gene distances of c-myc genes, centromeric region of chromosome 8 and chromosome 8 domains were found early after the induction of granulocytic differentiation by dimethyl sulfoxide (DMSO) or retinoic acid (RA); the size of the chromosome 8 domains was rapidly reduced. In differentiated cells, c-myc is located at greater distances from the centromeric regions of chromosome 8. These results support the idea that relocation of the c-myc gene to the nuclear periphery and the condensation of the chromosome 8 domain might be associated with the c-myc gene expression due to common kinetics during granulocytic differentiation.

Detection of hyperdiploid malignant cells in body cavity effusions by fluoresence in situ hybridization on ThinPrep slides

BACKGROUND

Benign body cavity effusions sometimes cannot be distinguished from malignant ones by conventional cytology. The authors performed fluorescence in situ hybridization (FISH) on ThinPrep slides using chromosome specific probes to see if hyperdiploid malignant cells could be detected in 20 body cavity effusions. The results were then compared with those of conventional cytology.

METHODS

A total of 20 body cavity effusions from 19 patients were studied using conventional cytology and FISH. Probes specific for chromosomes 3, 8, 10, and 12 were used to detect hyperdiploidy on ThinPrep slides (Cytyc Corporation, Boxborough, MA).

RESULTS

A total of 13 patients had malignant conditions (either prior history of malignancy or the presence of malignancy anywhere in the body). Conventional cytology and FISH were both positive in 5 of these patients (6 samples) and negative in 2 patients. The results for one sample were inconclusive by both methods. There were 5 discrepant cytology-FISH results in patients with malignant conditions. One sample was positive by FISH and negative by cytology, one was positive by FISH and "atypical" by cytology, and three were inconclusive by FISH and negative by cytology. FISH results were either negative (in 4 samples) or inconclusive (in 2 samples) in the 6 patients with benign conditions.

CONCLUSIONS

FISH can detect hyperdiploid malignant cells in body cavity effusions and is especially useful when the major cell population consists of malignant cells that cannot be differentiated from mesothelial or "atypical" cells. It is less useful in detecting a small population of malignant cells hidden in an inflammatory or reactive cell background. More studies are needed to establish diagnostic criteria further and to assess the clinical usefulness of this procedure.

Potential markers of aggressiveness in prostatic intraepithelial neoplasia detected by fluorescence in situ hybridization

OBJECTIVE

High-grade prostatic intraepithelial neoplasia (PIN) represents the most likely precursor of prostatic adenocarcinoma. In this review, we discuss the utility of different techniques of interphase fluorescence in situ hybridization (FISH) in evaluating the genetic association between PIN and adenocarcinoma.

METHODS AND RESULTS

Although the proportion of PIN and prostatic carcinoma foci that have chromosomal anomalies is similar, foci of carcinoma often have more alterations. This supports the hypothesis that PIN is a precursor of carcinoma. In some prostates, however, PIN foci have more alterations than matched carcinoma foci, suggesting that PIN foci can sometimes undergo more extensive chromosome evolution than carcinoma foci. Gain of chromosome 8 is the most common numerical alteration in prostatic carcinoma and PIN foci, and is associated with increasing cancer stage and grade. Thus, genes on chromosome 8 may play a role in the initiation and progression of prostatic carcinoma. One primary tumor focus usually shares chromosomal anomalies with associated lymph node metastases, implying that only one primary lesion acquires genetic alterations that allow it to escape the prostate.

CONCLUSIONS

PIN and prostatic carcinoma have similar genetic changes. This supports the hypothesis that PIN is often a precursor of carcinoma. Genes on chromosome 8 may play a role in both initiation and progression of prostatic carcinoma.

Atypical adenomatous hyperplasia of the prostate: a critical review

AIMS

The aim of this report is to review the literature concerning atypical adenomatous hyperplasia (AAH) with specific regard to evidence in support of or refuting its role as a precursor lesion for prostatic adenocarcinoma.

METHODS

The available literature was collected and critically reviewed. In addition, recently reported (abstract) but as yet unpublished data were included. Particular attention was focused on biological studies.

RESULTS

There is considerable morphologic evidence suggesting that AAH is associated with low-grade (Gleason patterns 1 and 2) adenocarcinoma arising in the transition zone. Only limited biologic studies have been performed. There is weak and limited data to indicate that AAH has a proliferation rate higher than hyperplasia but lower than adenocarcinoma. AAH is diploid, as are most examples of low-grade adenocarcinoma. A few markers (blood group antigens, peanut agglutinin) show similar patterns of expression in AAH and adenocarcinoma while others (carbohydrate D-galactose-N-acetyl-D-galactosamine) do not. Recent cytogenetic analyses have detected abnormalities of chromosome 8 in a very small proportion (4-6%) of cases of AAH studied.

CONCLUSIONS

Presently, the only strong evidence linking AAH to adenocarcinoma is morphologic. The few biologic and molecular/cytogenetic studies performed have not provided convincing evidence to support or refute this possibility. Additional studies are required. Finally, in comparative studies of AAH with adenocarcinoma, the latter should include low-grade transition zone tumors.

Unfavourable outcome of a patient with M2 acute non lymphocytic leukemia and a 47,XY,t(5;7)(q34;q21), +8 karyotype

We report a patient with M2 acute non-lymphocytic leukemia and a complex karyotype: 47,XY,t(5;7)(q34;q21), +8. After chemotherapy with Daunomycin and Arabinosyl Cytosine, a complete remission was reached, but two months later he relapsed and died because of sepsis. Only 5 other cases with translocations involving chromosomes 5 and 7 have been described, but with different breakpoints. Several genes related to cell proliferation and maturation have been identified on the long arms of chromosomes 5 and 7. The possible involvement of specific genes located at or very close to the breakpoints is hypothesized.