Pathogenesis and prognostication in acute lymphoblastic leukemia

The progress in the relationship between trace elements and acute lymphoblastic leukemia

Trace elements are very important substances with low content in the human body. If the content of some trace elements changes, they are also related to diseases. Acute lymphoblastic leukemia (ALL) is a malignant blood tumor, and its relationship with trace elements has also been a concern by scholars. Not only have the trace element levels in ALL patients changed, but the efficacy of different treatment methods has also been linked to the corresponding trace element changes. The characteristics of ALL may be related to the dysregulation of differentiation and proliferation of lymphoid precursor cells. Cell proliferation and differentiation are often affected by changes in DNA levels. However, trace elements are involved in DNA damage and repair mechanisms. In recent years, as an increasing number of studies believe that ALL is related to the abnormal metabolism of trace elements in the body, this paper intends to discuss the research progress on the relationship between trace elements and ALL to provide more information on trace elements for the diagnosis, treatment, and prevention of ALL.

Viral Agents as Potential Drivers of Diffuse Large B-Cell Lymphoma Tumorigenesis

Among numerous causative agents recognized as oncogenic drivers, 13% of total cancer cases occur as a result of viral infections. The intricacy and diversity of carcinogenic processes, however, raise significant concerns about the mechanistic function of viruses in cancer. All tumor-associated viruses have been shown to encode viral oncogenes with a potential for cell transformation and the development of malignancies, including diffuse large B-cell lymphoma (DLBCL). Given the difficulties in identifying single mechanistic explanations, it is necessary to combine ideas from systems biology and viral evolution to comprehend the processes driving viral cancer. The potential for more efficient and acceptable therapies lies in targeted medicines that aim at viral proteins or trigger immune responses to either avoid infection or eliminate infected or cancerous cells. In this review, we aim to describe the role of viral infections and their mechanistic approaches in DLBCL tumorigenesis. To the best of our knowledge, this is the first review summarizing the oncogenic potential of numerous viral agents in DLBCL development.

Association of Toll-like receptors polymorphisms with the risk of acute lymphoblastic leukemia in the Brazilian Amazon

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children in childhood. Single-nucleotide polymorphism (SNPs) in key molecules of the immune system, such as Toll-like receptors (TLRs) and CD14 molecules, are associated with the development of several diseases. However, their role in ALL is unknown. A case–control study was performed with 152 ALL patients and 187 healthy individuals to investigate the role of SNPs in TLRs and the CD14 gene in ALL. In this study, TLR6 C > T rs5743810 [OR: 3.20, 95% CI: 1.11–9.17, p = 0.003) and TLR9 C > T rs187084 (OR: 2.29, 95% CI: 1.23–4.26, p = 0.000) seems to be a risk for development of ALL. In addition, the TLR1 T > G rs5743618 and TLR6 C > T rs5743810 polymorphisms with protection against death (OR: 0.17, 95% IC: 0.04–0.79, p = 0.008; OR: 0.48, 95% IC: 0.24–0.94, p = 0.031, respectively). Our results show that SNPs in TLRs genes may be involved in the pathogenesis of ALL and may influence clinical prognosis; however, further studies are necessary to elucidate the role of TLR1, TLR4, TLR5, TLR6, TLR9 and CD14 polymorphisms in this disease.

RUNX1 and RUNX3 Genes Expression Level in Adult Acute Lymphoblastic Leukemia-A Case Control Study

The genetic factors of adult acute lymphoblastic leukemia (ALL) development are only partially understood. The Runt-Related Transcription Factor (RUNX) gene family play a crucial role in hematological malignancies, serving both a tumor suppressor and promoter function. The aim of this study was the assessment of relative RUNX1 and RUNX3 genes expression level among adult ALL cases and a geographically and ethnically matched control group. The relative RUNX1 and RUNX3 genes expression level was assessed by qPCR. The investigated group comprised 60 adult patients newly diagnosed with ALL. The obtained results were compared with a group of 40 healthy individuals, as well as clinical and hematological parameters of patients, and submitted for statistical analysis. ALL patients tend to have significantly higher RUNX1 gene expression level compared with controls. This observation is also true for risk group stratification where high-risk (HR) patients presented higher levels of RUNX1. A higher RUNX1 transcript level correlates with greater leukocytosis while RUNX3 expression is reduced in Philadelphia chromosome bearers. The conducted study sustains the hypothesis that both a reduction and increase in the transcript level of RUNX family genes may be involved in leukemia pathogenesis, although their interaction is complex. In this context, overexpression of the RUNX1 gene in adult ALL cases in particular seems interesting. Obtained results should be interpreted with caution. Further analysis in this research field is needed.

Induction of Cell Death in the Human Acute Lymphoblastic Leukemia Cell Line Reh by Infection with Rotavirus Isolate Wt1-5

Cancer is a major health problem that poses a great challenge to health care systems worldwide. Tools for cancer treatment have rapidly advanced in recent years, resulting in therapeutic strategies which are alternative and complementary to conventional treatment. To identify the cell surface receptors used by a tumor cell-adapted rotavirus and the cell death markers induced by its infection, we use Wt1-5, a rotavirus isolate recently adapted to tumor cells, to infect the human acute lymphoblastic leukemia cell line, Reh. The expression of cell surface receptors used by Wt1-5 was determined using flow cytometry and an antibody blocking assay to test for their implication in virus infection. Viral antigens and cell death markers induced by rotavirus infection were followed by flow cytometric analysis. The present study showed that rotavirus Wt1-5 was able to use cell surface proteins such as heat shock proteins (HSPs) 90, 70, 60 and 40, Hsc70, PDI and integrin β3. Rotavirus Wt1-5 induced cytotoxic effects including changes in cell membrane permeability, alteration of mitochondrial membrane potential, DNA fragmentation and activation of cell death signaling. Wt1-5 deserves to be further studied as a candidate oncolytic agent due to its ability to induce apoptosis in lymphoblastic leukemia-derived cells.

Pathogenesis of pediatric B-cell acute lymphoblastic leukemia: Molecular pathways and disease treatments

B-cell acute lymphoblastic lymphoma (B-ALL) is a disease found mainly in children and in young adults. B-ALL is characterized by the rapid proliferation of poorly differentiated lymphoid progenitor cells inside the bone marrow. In the United States, ~4,000 of these patients are diagnosed each year, accounting for ~30% of childhood cancer types. The tumorigenesis of the disease involves a number of abnormal gene expressions (including TEL-AML1, BCR-ABL-1, RAS and PI3K) leading to dysregulated cell cycle. Risk factors of B-ALL are the history of parvovirus B 19 infection, high birth weight and exposure to environmental toxins. These risk factors can induce abnormal DNA methylation and DNA damages. Treatment procedures are divided into three phases: Induction, consolidation and maintenance. The goal of treatment is complete remission without relapses. Apart from traditional treatments, newly developed approaches include gene targeting therapy, with the aim of wiping out leukemic cells through the inhibition of mitogen-activated protein kinases and via c-Myb inhibition enhancing sensitivity to chemotherapy. To evaluate the efficacy of ongoing treatments, several indicators are currently used. The indicators include the expression levels of microRNAs (miRs) miR-146a, miR-155, miR-181a and miR-195, and soluble interleukin 2 receptor. Multiple drug resistance and levels of glutathione reductase can affect treatment efficacy through the increased efflux of anti-cancer drugs and weakening the effect of chemotherapy through the reduction of intracellular reactive oxygen species. The present review appraised recent studies on B-ALL regarding its pathogenesis, risk factors, treatments, treatment evaluation and causes of disease relapse. Understanding the mechanisms of B-ALL initiation and causes of treatment failure can help physicians improve disease management and reduce relapses.

Nanomedicines for the treatment of hematological malignancies

Hematological malignancies (HM) are a collection of malignant transformations originating from cells in the primary or secondary lymphoid organs. Leukemia, lymphoma, and multiple myeloma comprise the three major types of HM. Current treatment consists of bone marrow transplantation, radiotherapy, immunotherapy and chemotherapy. Although, many chemotherapeutic drugs are clinically available for the treatment of HM, the use of these agents is limited due to dose-related toxicity and lack of specificity to tumor tissue. Moreover, the poor pharmacokinetic profile of most of the chemotherapeutics requires high dosage and frequent administration to maintain therapeutic levels at the target site, both increasing adverse effects. This underlines an urgent need for a suitable drug delivery system to improve efficacy, safety, and pharmacokinetic properties of conventional therapeutics. Nanomedicines have proven to enhance these properties for anticancer therapeutics. The most extensively studied nanomedicine systems are lipid-based nanoparticles and polymeric nanoparticles. Typically, nanomedicines are small sub-micron sized particles in the size range of 20-200 nm. The biocompatible and biodegradable nature of nanomedicines makes them attractive vehicles to improve drug delivery. Their small size allows them to extravasate and accumulate at malignant sites passively by means of the enhanced permeability and retention (EPR) effect, resulting from rapid angiogenesis and inflammation. Moreover, the specificity to the target tissue can be further enhanced by surface modification of nanoparticles. This review describes currently available therapies as well as limitations and potential advantages of nanomedicine formulations for treatment of various types of HM. Additionally, recent investigational and approved nanomedicine formulations and their limited applications in HM are discussed.

New Challenges in Targeting Signaling Pathways in Acute Lymphoblastic Leukemia by NGS Approaches: An Update

The identification and study of genetic alterations involved in various signaling pathways associated with the pathogenesis of acute lymphoblastic leukemia (ALL) and the application of recent next-generation sequencing (NGS) in the identification of these lesions not only broaden our understanding of the involvement of various genetic alterations in the pathogenesis of the disease but also identify new therapeutic targets for future clinical trials. The present review describes the main deletions, amplifications, sequence mutations, epigenetic lesions, and new structural DNA rearrangements detected by NGS in B-ALL and T-ALL and their clinical importance for therapeutic procedures. We reviewed the molecular basis of pathways including transcriptional regulation, lymphoid differentiation and development, TP53 and the cell cycle, RAS signaling, JAK/STAT, NOTCH, PI3K/AKT/mTOR, Wnt/β-catenin signaling, chromatin structure modifiers, and epigenetic regulators. The implementation of NGS strategies has enabled important mutated genes in each pathway, their associations with the genetic subtypes of ALL, and their outcomes, which will be described further. We also discuss classic and new cryptic DNA rearrangements in ALL identified by mRNA-seq strategies. Novel cooperative abnormalities in ALL could be key prognostic and/or predictive biomarkers for selecting the best frontline treatment and for developing therapies after the first relapse or refractory disease.

MGMT promoter methylation as a potential prognostic marker for acute leukemia

INTRODUCTION

It has been proved that genetic and epigenetic changes play a significant role in the development and progression of acute leukemia. The aim of our study was to evaluate the frequency and prognostic implications of genetic and epigenetic alterations in p15, MGMT, DNMT3A and TP53 genes in acute leukemias.

MATERIAL AND METHODS

We included in the study 59 patients with acute leukemia. Evaluation of TP53 and DNMT3A mutations was performed using sequencing analysis and PCR-RFLP, respectively. Methylation status of MGMT and p15 genes was evaluated using MSP and COBRA, respectively. For assessment of global DNA methylation ELISA-based kit was used.

RESULTS

We found that overall survival was higher for ALL patients. MGMT promoter methylation was significantly associated with patients age at the time of diagnosis (p = 0.03). TP53 and DNMT3A mutations were observed only in AML patients (16.67% and 8.8%, respectively). Patients with acute leukemia and p15 promoter methylation had significantly more frequently mutated TP53 gene (p = 0.04) and AML patients with p15 promoter methylation had significantly more frequently detected global hypomethylation of DNA (p = 0.009). In the group of ALL patients we noted an opposite trend: only patients negative for p15 promoter methylation were characterized by global DNA hypomethylation.

CONCLUSIONS

Our findings demonstrate that MGMT promoter methylation can have a considerable impact on the development of acute leukemia in older patients. DNMT3A and TP53 mutations may play a significant role in AML development. However, further studies conducted in a larger cohort of patients are needed to determine its clinical utility.

A novel IGH@ gene rearrangement associated with CDKN2A/B deletion in young adult B-cell acute lymphoblastic leukemia

Acquired copy number changes are common in acute leukemia. They are reported as recurrent amplifications or deletions (del), and may be indicative of involvement of oncogenes or tumor suppressor genes in acquired disease, as well as serving as potential biomarkers for prognosis or as targets for molecular therapy. The present study reported a gain of copy number of 14q13 to 14q32, leading to immunoglobulin heavy chain locus splitting in a young adult female. To the best of our knowledge, this rearrangement has not been previously reported in B-cell acute lymphoblastic leukemia (ALL). Low resolution banding cytogenetics performed at the time of diagnosis revealed a normal karyotype. However, retrospective application of fluorescence in situ hybridization (FISH) banding and locus-specific FISH probes, as well as multiplex ligation-dependent probe amplification and high resolution array-comparative genomic hybridization, revealed previously hidden aberrations. Overall, a karyotype of 46, XX, del(9) (p21.3 p21.3),derivative(14) (pter-> q32.33:: q32.33-> q13 ::q32.33-> qter) was determined. The patient was treated according to the Polish Adult Leukemia Group protocol and achieved complete remission. The results of the present study indicate that a favorable prognosis is associated with these aberrations when the aforementioned treatment is administered.

Overexpression of MALT1-A20-NF-κB in adult B-cell acute lymphoblastic leukemia

Background

A20 is a dual inhibitor of NF-κB activation and apoptosis in the tumor necrosis factor receptor 1 signaling pathway, and both are related to tumorigenesis. A20 is frequently inactivated by deletions and/or mutations in several B and T cell lymphoma subtypes; however, knowledge of the role of A20 in B-cell acute lymphoblastic leukemia (B-ALL) remains limited. In this study, we characterized the A20 gene expression pattern, the expression level of its upstream regulating factor MALT1, and its downstream target NF-κB in adult B-ALL.

Methods

The expression level of MALT1, A20 and NF-κB1 was detected in peripheral blood mononuclear cells (PBMCs) from 20 patients with adult B-ALL (including 12 de novo B-ALL and 8 refractory/relapse B-ALL cases), and nine patients with B-ALL in complete remission (CR) using real-time PCR. Sixteen healthy individuals served as controls.

Results

Significant A20 overexpression was found in the B-ALL (median: 13.489) compared with B-ALL CR (median: 3.755) (P = 0.003) patients and healthy individuals (median: 8.748) (P = 0.002), while there was no significant difference in A20 expression between B-ALL CR patients and healthy individuals (P = 0.107). Interestingly, the A20 expression level in the B-ALL samples was relatively different with approximately 50% of the B-ALL cases showing a relatively high A20 expression level, while the remaining 50% cases demonstrated slight upregulation or a similar expression level as the healthy controls. However, there was no significant difference in the A20 expression level between de novo B-ALL (median 12.252) and refractory/relapse B-ALL patients (median 21.342) (P = 0.616). Similarly, a significantly higher expression level of NF-κB1 was found in the B-ALL (median 1.062) patients compared with healthy individuals (median 0.335) (P < 0.0001), while the NF-κB1 expression level was downregulated in the B-ALL CR group (median 0.339), which was significantly lower than that in those with B-ALL (P = 0.001). Moreover, the MALT1 expression level in B-ALL was upregulated (median 1.938) and significantly higher than that in healthy individuals (median 0.677) (P = 0.002) and B-ALL CR patients (median 0.153) (P = 0.008). The correlation of the expression levels of all three genes was lost in B-ALL.

Conclusions

We found that MALT1-A20-NF-κB is overexpressed in adult B-ALL, which may be related to the pathogenesis of B-ALL, and this pathway may be considered a potentially attractive target for the development of B-ALL therapeutics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-015-0222-0) contains supplementary material, which is available to authorized users.

High rates of submicroscopic aberrations in karyotypically normal acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) is not a single uniform disease. It consists of several subgroups with different cytogenetic and molecular genetic aberrations, clinical presentations and outcomes. Banding cytogenetics plays a pivotal role in the detection of recurrent chromosomal rearrangements and is the starting point of genetic analysis in ALL, still. Nowadays, molecular (cyto)genetic tools provide substantially to identify previously non-detectable, so-called cryptic chromosomal aberrations in ALL. However, ALL according to banding cytogenetics with normal karyotype - in short cytogenetically normal ALL (CN-ALL) - represent up to ~50 % of all new diagnosed ALL cases. The overall goal of this study was to identify and characterize the rate of cryptic alterations in CN-ALL and to rule out if one single routine approach may be sufficient to detect most of the cryptic alterations present.

Results

Sixty-one ALL patients with CN-ALL were introduced in this study. All of them underwent high resolution fluorescence in situ hybridization (FISH) analysis. Also DNA could be extracted from 34 ALL samples. These DNA-samples were studied using a commercially available MLPA (multiplex ligation-dependent probe amplification) probe set directed against 37 loci in hematological malignancies and/or array-comparative genomic hybridization (aCGH). Chromosomal aberrations were detected in 21 of 61 samples (~34 %) applying FISH approaches: structural abnormalities were present in 15 cases and even numerical ones were identified in 6 cases. Applying molecular approaches copy number alterations (CNAs) were detected in 27/34 samples. Overall, 126 CNAs were identified and only 34 of them were detectable by MLPA (~27 %). Loss of CNs was identified in ~80 % while gain of CNs was present in ~20 % of the 126 CNAs. A maximum of 13 aberrations was detected per case; however, only one aberration per case was found in 8 of all in detail studied 34 cases. Of special interest among the detected CNAs are the following new findings: del(15)(q26.1q26.1) including CHD2 gene was found in 20 % of the studied ALL cases, dup(18)(q21.2q21.2) with the DCC gene was present in 9 % of the cases, and the CDK6 gene in 7q21.2 was deleted in 12 % of the here in detail studied ALL cases.

Conclusions

In conclusion, high resolution molecular cytogenetic tools and molecular approaches like MLPA and aCGH need to be combined in a cost-efficient way, to identify disease and progression causing alterations in ALL, as majority of them are cryptic in banding cytogenetic analyses.

Electronic supplementary material

The online version of this article (doi:10.1186/s13039-015-0153-4) contains supplementary material, which is available to authorized users.

Novel Cryptic Rearrangements in Adult B-Cell Precursor Acute Lymphoblastic Leukemia Involving the MLL Gene

MLL (mixed-lineage-leukemia) gene rearrangements are typical for acute leukemia and are associated with an aggressive course of disease, with a worse outcome than comparable case, and thus require intensified treatment. Here we describe a 69-year-old female with adult B cell precursor acute lymphoblastic leukemia (BCP-ALL) with hyperleukocytosis and immunophenotype CD10- and CD19+ with cryptic MLL rearrangements. G-banding at the time of diagnosis showed a normal karyotype: 46,XX. Molecular cytogenetics using multitude multicolor banding (mMCB) revealed a complex rearrangement of the two copies of chromosome 11. However, a locus-specific probe additionally identified that the MLL gene at 11q23.3 was disrupted, and that the 5' region was inserted into the chromosomal sub-band 4q21; thus the aberration involved three chromosomes and five break events. Unfortunately, the patient died six months after the initial diagnosis from serious infections and severe complications. Overall, the present findings confirm that, by far not all MLL aberrations are seen by routine chromosome banding techniques and that fluorescence in situ hybridization (FISH) should be regarded as standard tool to access MLL rearrangements in patients with BCP-ALL.