Agata Pastorczak

Role of 657del5 NBN mutation and 7p12.2 (IKZF1), 9p21 (CDKN2A), 10q21.2 (ARID5B) and 14q11.2 (CEBPE) variation and risk of childhood ALL in the Polish population.

Recent studies have shown that SNPs mapping to 7p12.2 (IKZF1), 9p21 (CDKN2A), 10q21.2 (ARID5B), and 14q11.2 (CEBPE) and carrier status for recessively inherited Nijmegen Breakage syndrome (NBS) influence childhood acute lymphoblastic leukemia (ALL) risk. To examine these relationship, we analysed 398 ALL cases and 731 controls from Poland. Statistically significant association between genotype at 7p12.2 (IKZF1), 10q21.2 (ARID5B) and the NBS associated locus, 8q21.3 (NBN) and ALL risk was found; odds ratios (ORs), 1.34 (P=0.002), 1.33 (P=0.003), and 1325.21 (P=0.0028), respectively. These data provide further insights into the biological basis of ALL highlighting the existence of both common and rare disease susceptibility variants.

Polymorphisms of TNF and IL‐10 genes and clinical outcome of patients with chronic lymphocytic leukemia

Genetic variations in tumor necrosis factor (TNF) and interleukin‐10 (IL‐10) were reported to influence susceptibility to and outcome of patients with non‐Hodgkin lymphoma. Therefore, we investigated whether single nucleotide polymorphisms in TNF and IL‐10 may play a role in the clinical course of patients with chronic lymphocytic leukemia (CLL). TNF‐308G>A, IL‐10‐3575T>A, and IL‐10‐1082A>G seem to be functionally relevant, were genotyped in 292 previously untreated patients with CLL. The control group consisted of 192 randomly selected blood donors. The patients carrying TNF‐308GG and IL‐10‐1082AA genotypes presented a higher 3‐year treatment‐free survival (56.6 vs. 40.6%, P = 0.05) as well as a 10‐year overall survival (OS) rates (92.3 vs. 57.6%, P = 0.005) than those with other TNF‐308 and IL‐10‐1082 genotype combinations. Multivariate analysis demonstrated the Rai stage (P = 0.0002), IGHV mutation status (P = 0.01), TNF‐308G>A (P = 0.03), and TNF/IL‐10 polymorphism‐based risk groups (P = 0.05) to be independent factors predicting OS. When the mutated IGHV patients were analyzed, the homozygotes TNF‐308GG and IL‐10‐1082AA presented a higher 10‐year OS rate than those carrying other TNF‐308 and IL‐10‐1082 genotypes (100 vs. 67.7%, P = 0.01). In the unmutated IGHV patients, only the TNF‐308G>A polymorphism influenced OS. The genetic variations in TNF and IL‐10 genes work as independent predictors of survival and may play a role in the clinical course of CLL. It suggests inherited ability of the host to shift the balance between the Th1 and Th2 response, which in turn might contribute to the pathogenesis and prognosis of B‐cell malignancies.

Biallelic loss of CDKN2A is associated with poor response to treatment in pediatric acute lymphoblastic leukemia

Abstract The inactivation of tumor suppressor genes located within 9p21 locus (CDKN2A, CDKN2B) occurs in up to 30% of children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but its independent prognostic significance remains controversial. In order to investigate the prognostic impact of deletions and promoter methylation within 9p21, 641 children with newly diagnosed BCP-ALL using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) were investigated. A total of 169 (26.4%) microdeletions in 9p21 were detected, of which 71 were homozygous. Patients with CDKN2A homozygous deletions were older at diagnosis (p < .001), more frequently steroid resistant (p = .049), had higher WBC count (p < .001), higher MRD at Day 15 (p = .013) and lower relapse-free survival [p = .028, hazard ratio: 2.28 (95% confidence interval: 1.09–4.76)] than patients without these alterations. CDKN2A homozygous deletions coexisted with IKZF1 and PAX5 deletions (p < .001). In conclusion, CDKN2A homozygous deletions, but not promoter methylation, are associated with poor response to treatment and increased relapse risk of pediatric BCP-ALL.

Novel severe hemophilia A and moyamoya (SHAM) syndrome caused by Xq28 deletions encompassing F8 and BRCC3 genes

To the editor: A 10-year-old boy with severe hemophilia A and no other obvious morbidity arrived at the hospital with focal neurological signs and a suspected intracranial hemorrhage. Surprisingly, radiological studies demonstrated an ischemic stroke. Neither active thromboembolism nor genetic

Asparagine synthetase (ASNS) gene polymorphism is associated with the outcome of childhood acute lymphoblastic leukemia by affecting early response to treatment

The polymorphism of 14-bp tandem repeat sequence located in the ASNS gene probably acts as a transcriptional enhancer element and leads to higher expression of the gene in carriers of more than 2 repeats (>R2). We searched for an association with disease outcome in 264 children with ALL. A multivariate proportional hazard regression model adjusted for age at diagnosis (HR (95%CI)=1.05 (1.04-1.09)) and high-risk group (HR(95%CI)=3.47 (1.74-6.88)) revealed that R3 carriers with a poor response at day 15 had an increased risk of events, HR (95%CI)=2.72 (1.06-6.96). These results suggest a conditional interaction between the ASNS polymorphism and an early response to chemotherapy among pediatric patients with ALL.

Clinical course and therapeutic implications for lymphoid malignancies in Nijmegen breakage syndrome

Nijmegen breakage syndrome (NBS, MIM #251260) is an autosomal recessive chromosomal instability disorder. Majority of patients affected are of Slavic origin and share the same founder mutation of 657del5 within the NBN gene encoding protein involved in DNA double-strand breaks repair. Clinically, this is characterized by a microcephaly, immunodeficiency and a high incidence of pediatric malignancies, mostly lymphomas and leukemias. Anticancer treatment among patients with NBS is challenging because of a high risk of life threatening therapy-related toxicity including severe infections, bone marrow failure, cardio- and nephrotoxicity and occurrence of secondary cancer. Based on systemic review of available literature and the Polish acute lymphoblastic leukemia database we concluded that among patients with NBS, these who suffered from clinically proven severe immunodeficiency are at risk of the complications associated with oncological treatment. Thus, in this group it reasonable to reduce chemotherapy up to 50% especially concerning anthracyclines methotrexate, alkylating agents and epipodophyllotoxines, bleomycin and radiotherapy should be omitted. Moreover, infection prophylaxis using intravenous immunoglobulin supplementation together with antifungal and antibacterial agent is recommended. To replace radiotherapy or some toxic anticancer agents targeted therapy using monoclonal antibodies and kinase inhibitors or bone marrow transplantation with reduced-intensity conditioning should be considered in some cases, however, this statement needs further studies.

The Role of Histone Protein Modifications and Mutations in Histone Modifiers in Pediatric B-Cell Progenitor Acute Lymphoblastic Leukemia

While cancer has been long recognized as a disease of the genome, the importance of epigenetic mechanisms in neoplasia was acknowledged more recently. The most active epigenetic marks are DNA methylation and histone protein modifications and they are involved in basic biological phenomena in every cell. Their role in tumorigenesis is stressed by recent unbiased large-scale studies providing evidence that several epigenetic modifiers are recurrently mutated or frequently dysregulated in multiple cancers. The interest in epigenetic marks is especially due to the fact that they are potentially reversible and thus druggable. In B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) there is a relative paucity of reports on the role of histone protein modifications (acetylation, methylation, phosphorylation) as compared to acute myeloid leukemia, T-cell ALL, or other hematologic cancers, and in this setting chromatin modifications are relatively less well studied and reviewed than DNA methylation. In this paper, we discuss the biomarker associations and evidence for a driver role of dysregulated global and loci-specific histone marks, as well as mutations in epigenetic modifiers in BCP-ALL. Examples of chromatin modifiers recurrently mutated/disrupted in BCP-ALL and associated with disease outcomes include MLL1, CREBBP, NSD2, and SETD2. Altered histone marks and histone modifiers and readers may play a particular role in disease chemoresistance and relapse. We also suggest that epigenetic regulation of B-cell differentiation may have parallel roles in leukemogenesis.

Polymorphism in IKZF1 gene affects age at onset of childhood acute lymphoblastic leukemia

Abstract Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, characterized by a peak of incidence between 2 and 5 years. Since recently conducted genome-wide association (GWA) studies revealed that the common low-penetrance susceptibility allele at 7p12.2 (IKZF1 gene) confers an increased risk of pediatric ALL, we investigated whether the risk allele at rs4132601 also coexists with well-established prognostic factors, among 508 Polish pediatric patients with newly diagnosed ALL. Additionally, to verify whether the risk allele is favored by somatic tumor evolution, we examined the incidence of IKZF1 deletions in leukemic clones derived from 153 previously genotyped cases of pediatric ALL. Results of the analysis provide statistically significant support for an association between the rs4132601 polymorphic site and age at diagnosis of childhood ALL (p = 0.04). No association between allele variant and occurrence of IKZF1 deletions was found. These data provide further evidence of a biological role of gene variants in the development of ALL.

Genomic profiling of Acute lymphoblastic leukemia in ataxia telangiectasia patients reveals tight link between ATM mutations and chromothripsis

Recent developments in sequencing technologies led to the discovery of a novel form of genomic instability, termed chromothripsis. This catastrophic genomic event, involved in tumorigenesis, is characterized by tens to hundreds of simultaneously acquired locally clustered rearrangements on one chromosome. We hypothesized that leukemias developing in individuals with Ataxia Telangiectasia, who are born with two mutated copies of the ATM gene, an essential guardian of genome stability, would show a higher prevalence of chromothripsis due to the associated defect in DNA double-strand break repair. Using whole-genome sequencing, fluorescence in situ hybridization and RNA sequencing, we characterized the genomic landscape of Acute Lymphoblastic Leukemia (ALL) arising in patients with Ataxia Telangiectasia. We detected a high frequency of chromothriptic events in these tumors, specifically on acrocentric chromosomes, as compared with tumors from individuals with other types of DNA repair syndromes (27 cases total, 10 with Ataxia Telangiectasia). Our data suggest that the genomic landscape of Ataxia Telangiectasia ALL is clearly distinct from that of sporadic ALL. Mechanistically, short telomeres and compromised DNA damage response in cells of Ataxia Telangiectasia patients may be linked with frequent chromothripsis. Furthermore, we show that ATM loss is associated with increased chromothripsis prevalence in additional tumor entities.

Preserved global histone H4 acetylation linked to ETV6-RUNX1 fusion and PAX5 deletions is associated with favorable outcome in pediatric B-cell progenitor acute lymphoblastic leukemia

Epigenetic dysregulation is a hallmark of cancer executed by a number of complex processes the most important of which converge on DNA methylation and histone protein modifications. Epigenetic marks are potentially reversible and thus promising drug targets. In the setting of acute lymphoblastic leukemia (ALL) they have been associated with clinicopathological features including risk of relapse or molecular subgroups of the disease. Here, using immunocytochemistry of bone marrow smears from diagnosis, we studied global histone H4 acetylation, whose loss was previously linked to treatment failure in adults with ALL, in pediatric patients. We demonstrate that preserved global histone H4 acetylation is significantly associated with favorable outcome (RFS, EFS, OS) in children with B cell progenitor (BCP) ALL, recapitulating the findings from adult populations. Further, for the first time we demonstrate differential histone H4 acetylation in molecular subclasses of BCP-ALL including cases with ETV6-RUNX1 fusion gene or PAX5 deletion or deletions in genes linked to B cell development. We conclude global histone H4 acetylation is a prognostic marker and a potential therapeutic target in ALL.