Additional Chromosomal Aberrations Research Articles

Telomere Dysfunction in Pediatric Patients with Differences/Disorders of Sexual Development.

Peripheral blood lymphocytes were sampled from 35 DSD patients (mean age: 3.3 years; range 0-18 years) admitted to two hospital centers in Dakar. Peripheral blood lymphocytes from 150 healthy donors were used as a control. Conventional cytogenetics, telomere, and centromere staining followed by multiplex FISH, as well as FISH with SRY-specific probes, were employed. Cytogenetic analysis identified 19 male and 13 female patients with apparently normal karyotypes, two patients with Turner syndrome, and one patient with Klinefelter syndrome. Additional structural chromosome aberrations were detected in 22% of the patients (8/35). Telomere analysis revealed a reduction in mean telomere lengths of DSD patients compared to those of healthy donors of similar age. This reduction in telomere length was associated with an increased rate of telomere aberrations (telomere loss and the formation of telomere doublets) and the presence of additional chromosomal aberrations. To the best of our knowledge, this study is the first to demonstrate a correlation between telomere dysfunction and DSDs. Further studies may reveal the link between telomere dysfunction and possible mechanisms involved in the disease itself, such as DNA repair deficiency or specific gene mutations. The present study demonstrates the relevance of implementing telomere analysis in prenatal tests as well as in diagnosed genetic DSD disorders.

Spectrum of BCR-ABL mutations in Azerbaijanian imatinib-resistant patients with chronic myeloid leukemia.

Objective: BCR-ABL1 kinase domain (KD) mutations can lead to resistance to first- and second-generation tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). Here, we present the first report of the spectrum of mutations in the BCR-ABL1 KD of CML patients from Azerbaijan. Materials and methods: Samples for mutation screening were obtained from patients experiencing resistance to first line TKIs or from patients in acceleration phase (AP) or blast crisis (BC) at the time of diagnosis. The cDNA region corresponding to BCR-ABL1 KD was sequenced by pyrosequencing method. The χ2 test was used to assess the association of categorical variables between mutation-positive and -negative groups. In addition, the Kaplan-Meier method was applied to generate survival curves. Results: Eight different point mutations were identified in 22 (13.4%) out of 163 CML patients experiencing resistance to TKIs. The types of mutations detected were as follows: Contact binding site mutations 50% (11), SH2 domain mutations 27.4% (six), P-loop mutations 18.1% (four), and SH3 domain mutations accounting for 4.5% (one). The most common mutation was T315I, accounting for 5% (n = 8) of all patients. Significant association was identified between BCR-ABL1 mutations and additional chromosomal aberrations as well as between the mutations and disease phases (p < 0.05). Twelve out of 22 patients with BCR-ABL1 mutations and seven out of eight with T315I were in BC. Overall survival (OS) of the patients with BCR-ABL1 mutations was significantly lower comparing to the patients with no mutation (p < 0.05) and 8 patients with T315I mutation presented OS of 0%. Conclusion: T315I was the most commonly identified BCR-ABL1 mutation in TKI-resistant CML patients of Azerbaijani origin, being associated with disease progression and poor OS.

Patterns of chromosome abnormalities in a sample of Colombian patients with chronic myeloid leukemia

Chronic Myeloid Leukemia (CML) is characterized by the presence of the Philadelphia (Ph) chromosome, resulting from a translocation between chromosomes 9 and 22 that gives rise to the BCR-ABL1 fusion gene. The Ph chromosome is present in 95 % of CML cases. In 5 %-10 % of these cases Ph variants occur and, approximately 5 % of these cases present with additional chromosomal abnormalities (ACAs). In this work we describe the prevalence of chromosome abnormalities in a sample of Colombian CML patients. A descriptive cross-sectional study was conducted, analyzing cytogenetic and molecular data from 142 CML patients. Data were collected between 2016 and 2019 at the laboratory of Biogenética Diagnóstica S.A.S. Among the 142 patients were analyzed, 56 % were male, and the average age was 45 years. The Ph chromosome was observed in 81 % of the cases. Three-way chromosome variants involving chromosomes 3, 7, and 8 were detected. The most frequent additional chromosomal aberration was +der(22)t(9;22). Atypical patterns associated with poor prognosis were found, via FISH analyses, in 88.2 % of the patients. The BCR-ABL1 fusion gene was detected in 100 % of the 18 patients subjected RT-PCR tests. This retrospective study reveals intriguing findings regarding chromosomal abnormalities in Colombian patients with CML, including rare three-way chromosome variants and atypical FISH patterns associated with a poor prognosis.Further investigation is warranted to explore the clinical implications, prognosis, and survival outcomes associated with these cytogenetic findings in CML patients.

The study of the impact of additional chromosomal aberrations and c-MYC and BCR::ABL1 genes amplification on CML patient’s characteristics: relation to haematological parameters and patient outcome

BackgroundChronic myeloid leukaemia is characterised by genetic instability which results in additional cytogenetic aberrations that have been linked to progression to advanced phase. Genomic study linked amplified genes in the form of c-MYC and/or the rare BCR::ABL1 genes amplification to chronic myeloid leukaemia. The effect of these genes’ amplification on patients’ characteristics and disease progression still needs further study.This cross-sectional study aimed to investigate the frequency of additional chromosomal aberrations in addition to c-MYC and BCR::ABL1 genes amplification in chronic myeloid leukaemia patients and their impact on patient’s characteristics, disease progression, and level of remission. The study included cytogenetic analysis of 49 Philadelphia positive chronic myeloid leukaemia patients and investigation of c-MYC and BCR::ABL1 genes amplification by fluorescence in situ hybridization.ResultsPatients with additional chromosomal aberrations represented 36.7% and had significantly lower platelet count (P = 0.003) and higher blast count (P = 0.008). The acquisition of additional chromosomal aberrations was significantly higher in chronic myeloid leukaemia patients with advanced stages (P = 0.014). Follow-up of the patients for 6 months revealed significant higher frequency of additional chromosomal aberrations in patients with failure of remission (P < 0.0001). A highly significant association between cases with failure of molecular remission (P = 0.001) and co-existing additional chromosomal aberrations.Amplification of the c-MYC gene was detected in 6 cases. The cases with c-MYC amplification showed significantly higher peripheral blood and bone marrow blasts (P = 0.029 and P = 0.008, respectively) and significantly lower platelet count (P = 0.044). Amplification of c-MYC was significantly associated with additional chromosomal aberrations (P = 0.011). Molecular remission was not achieved in any of the instances with c-MYC amplification. A highly significant association between c-MYC amplification and poor patient outcome was detected (P = 0.002). BCR::ABL1 amplification was detected in three cases, and ABL amplification was detected in four cases. Patients with BCR::ABL1 amplification showed significantly higher blast count. BCR::ABL1 amplification was significantly associated with disease progression and failure of molecular remission (P = 0.002).ConclusionAdditional chromosomal aberrations, c-MYC amplification, and BCR:ABL1 amplification in chronic myeloid leukaemia stratify patients with disease progression, which may lead to better interventions and improved outcome in the future chronic myeloid leukaemia patients.

Disease Response Assessment Modalities in Chronic Myeloid Leukemia: Past, Present, and Future

AbstractChronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by the BCR::ABL1 fusion gene, which results from a reciprocal translocation between chromosome 9 and 22 t(9;22)(q34;q11). The use of tyrosine kinase inhibitor (TKI) against the chimeric BCR::ABL1 fusion protein has led to a paradigm shift in CML patient outcomes. Despite generational advancements in TKI, a fraction of patients harbor residual disease or exhibit resistance to TKI. The importance of disease monitoring and detection of resistance mechanisms has gained prominence with increasing knowledge about disease evolution. In the past, cytogenetic techniques such as karyotyping and fluorescence in situ hybridization were widely utilized for monitoring disease and prognostication. These techniques had various challenges related to limited sensitivity in minimal residual disease (MRD) monitoring; however, their importance still holds in the detection of additional chromosomal aberrations and in cases with cryptic insertions, variants, and masked Philadelphia chromosome. Molecular genetics has evolved significantly from the past to the present times for MRD monitoring in CML patients. Qualitative reverse transcription polymerase chain reaction (RQ-PCR) can be performed at diagnosis to detect the BCR::ABL1 transcript, while quantitative RQ-PCR is the most widely used and well-standardized MRD monitoring method. The DNA-based assays demonstrated high sensitivity and specificity, with many efforts directed toward making the laborious step of BCR::ABL1 breakpoint characterization less tedious to increase the utility of DNA-based MRD approach in the future. Flow cytometric–based approaches for the detection of the BCR::ABL1 fusion protein have been under trial with a scope of becoming a more robust and convenient methodology for monitoring in the future. Upcoming techniques such as digital PCR and ultra-deep sequencing next-generation sequencing (UDS-NGS) have shown promising results in residual disease monitoring and detection of resistance mutations. Novel MRD monitoring systems that are independent of BCR::ABL1 fusion such as the detection of CD26+ leukemic stem cells and microRNA mutations are the future of residual disease monitoring, which can go up to the level of a single cell. In this review, we tried to discuss the evolution of most of the above-mentioned techniques encompassing the pros, cons, utility, and challenges for MRD monitoring and detection of TKI resistance mutations.

Echocardiographic measurements of left ventricular dimensions and function in newborns with omphalocele and pulmonary

PurposeThe purpose of this study was to explore echocardiographic parameters of the left ventricle (LV) in relation to the outcomes of omphalocele neonates with pulmonary hypertension (PH).MethodsThis retrospective study was conducted among omphalocele patients with PH born from 2019 to 2020. Patients in this study did not have additional severe malformations or chromosomal aberrations. Patients who died under palliative care were excluded. The echocardiographic parameters of LV were obtained within 24 h after birth. Clinical and outcomes data were recorded, echocardiograms evaluated for left ventricular internal dimension in end-diastole (LVIDd), end-diastolic volume (EDV), stroke volume (SV) and cardiac output index (CI), among others.ResultsThere were 18 omphalocele newborns with PH, of whom 14 survived and 4 died. Both groups were comparable in the baseline characteristics. Non-survival was associated with a smaller LV [LVIDd (12.2 mm versus15.7 mm, p < 0.05), EDV (3.5 ml versus 6.8 ml, p < 0.05)] and with worse systolic function [SV (2.3 ml versus 4.2 ml, p < 0.05), and CI (1.7 L/min/m2 versus 2.9 L/min/m2, p < 0.01)].ConclusionIn the cohort of omphalocele patients with PH, lower LVIDd, EDV, SV and CI were associated with mortality.Level of evidenceLevel III.

New Insights into the Nature of the 5q- Deletion Syndrome Based on Quantitative Measurement of BAALC- Expressing Stem Cell Burdens

A discovery of nonrandom recurrent interstitial aberration at the long arm of chromosome 5 was made by Van den Berghe et al. in 1974. For a long time, this entity was classified as myelodysplastic syndrome (MDS). Meanwhile, its definition as well as classification criteria were repeatedly changed due to both clinical studies and advances in new techniques. In particular an insufficiency of ribosome-forming protein (RPS14) gene was found soon after similar gene RPS19 discovery in patients with severe inherited Diamond-Blackfan anemia (DBA). It cannot be excluded that basic pathogenetic mechanisms, including participation of activated gene TP53, seem to be similar in both entities.&#x0D; This article for the first time presents the quantitative data on the BAALC expression in the majority (25/31) of patients tested with 5q- deletions to be under the cut-off values. It concerns a group of 14/16 patients with isolated 5q- anomaly, and 11 other cases in whom 5q- deletion was combined with additional non-identical chromosomal aberrations. On the contrary, this molecular parameter exceeded the cut-off levels in all (n=10) MDS patients without 5q- abnormality. Hence, these data might effectively support an assumption of a ribosomopathy in cases of isolated 5q- deletion. Since about 8-10 % of these patients are transformed into MDS and/or secondary AML, a possible exclusion of isolated 5q- deletion syndrome from MDS category should be discussed carefully and this assumption is needed an additional support in larger studies.

Impact of the type of ductus venosus agenesis and the presence of associated anomalies on prognosis

Objective: The Ductus Venosus (DV) connects the umbilical vein to the inferior vena cava. With a portocaval pressure gradient, the well-oxygenated blood in the ductus venosus accelerates towards the left sidewall of the inferior vena cava, directing the blood preferentially towards cephalic and coronary circulation through the foramen ovale (1). DV serves as a shunt, expanding to protect the heart and brain in hypoxic conditions. Ductus Venosus Agenesis (DVA) is a rare congenital abnormality with a prevalence of 0.03-0.07%. The type of DVA, along with any additional anatomical or chromosomal anomalies in fetuses with DVA, significantly affects the postnatal prognosis. Some fetuses with DVA develop normally, while others may experience growth retardation, heart defects, or other complications. In this study, we aimed to evaluate the frequency of associated anomalies in DVA cases, examine the impact of each type of DVA (intrahepatic and extrahepatic venous drainage) on prognosis, and contribute to the literature on this rare disease. Materials and Methods: We conducted a retrospective study of all cases diagnosed prenatally with DVA at a tertiary center between 2016-2019. Our study reviewed obstetric data, associated anomalies, other systemic anomalies, type of DVA, chromosomal or genetic anomalies, and perinatal and postnatal outcomes. Postnatal infants were followed up to the 6th month. Results: We identified 16 cases with ductus venosus agenesis. The type of DVA (intrahepatic-extrahepatic shunt), presence of chromosomal anomalies, accompanying ultrasonographic findings, and perinatal outcomes were recorded. Generally, in 7 out of the 16 cases, the umbilical vein drained into the portal system (44% - intrahepatic), and in 9 cases, it drained into the systemic venous system. Conclusion: DVA is a rare congenital abnormality with potentially significant implications for affected fetuses and infants. Early diagnosis, careful monitoring, and appropriate management strategies are crucial to optimize outcomes for these patients. There's a need for future research to better understand the underlying etiology and pathophysiology of DVA and to develop more effective treatment options for affected individuals.

The presence of additional cytogenetic aberrations in chronic myeloid leukemia cells at the time of diagnosis or their appearance on tyrosine kinase inhibitor therapy predicts the imatinib treatment failure

Currently used treatment of CML dramatically improved the prognosis of disease. However, additional chromosome aberrations (ACA/Ph+) are still one of the adverse prognostic factors. Objectivesevaluation of the impact of ACA/Ph+ appearance during disease outcome on the response to treatment. The study groupconsisted of 203 patients. The median time of follow-up was 72 months. ACA/Ph+ was found in 53 patients. Resultspatients were divided into four groups: standard risk, intermediate, high and very high risk. When ACA/Ph+ presence was documented at diagnosis time the optimal response was observed in 41.2%, 25%, and 0% of pts with intermediate, high and very high risk, respectively. If ACA/Ph+ were detected during imatinib treatment the optimal response was in 4.8% of patients. The risk of blastic transformation for patients with standard risk, intermediate, high and very high risk was 2.7%, 18.4%, 20% and 50%, respectively. Conclusionsthe presence of ACA/Ph+ at diagnosis time or their appearance on therapy seems to be clinically relevant not only in terms of the risk of blastic transformation but also in terms of the treatment failure. Gathering patients with various karyotypes and their responses to treatment would allow to set better guidelines and predictions.

Cytogenomic Profiling of Chronic Lymphocytic Leukaemia Patients Using DNA Microarray

Introduction: Chronic lymphocytic leukaemia (CLL) is the most frequent adult leukaemia in the Western world. The clinical presentation varies greatly, from very indolent cases to those with aggressive and fast advancing disease. This variation has significant implications for clinical approaches, therapeutic tactics, and, ultimately, survival durations from diagnosis. Acquired chromosomal aberrations play a key role in CLL aetiology. Due to difficulty to obtain abnormal metaphases for analysis, few methods such as fluorescence in-situ hybridization (FISH) and multiplex ligation-dependent probe assay (MLPA) were employed to detect chromosomal aberration however the methods are limited to specific locus only. Thus, this study is aimed to detect the chromosomal aberrations using DNA microarray platform. Methods: In this retrospective study, DNA archive obtained from 7 CLL patients which collected at diagnosis and subjected to Affymetrix CytoScan® 750K single nucleotide polymorphism (SNP) array following the manufacture procedure. The raw data obtained were analysed using the Chromosome Analysis Suite (ChAS) software (Affymetrix) using annotations of genome version GRCh38 (hg38). Result: Out of 7 patients, 4 of them showing deletion of 13q while 3 of them showing deletion of 14q in various region . Some of the deleted loci were too small (0.42-0.6Mb) to be detected by conventional cytogenetic analysis (CCA). There was also the presence of additional chromosomal aberrations that could be missed by CCA, FISH, or MLPA due to cryptic deletion or duplication that was as small as 0.4MB in size. Conclusion: The present study showed that low resolution chromosomal aberration was able to be detected using DNA microarray platform in comparison to CCA, FISH and MLPA.

Additional diagnostic value of CNV-seq over conventional karyotyping in prenatal diagnosis: A systematic review and meta-analysis.

To identify the additional diagnostic value of CNV-seq over conventional karyotyping on the part of chromosomal abnormalities in prenatal diagnosis. This was a systematic review conducted in accordance with PRISMA criteria. In order to clarify related research, PubMed, Web of Science databases (including Core Collection, BIOSIS Previews, MEDLINE, and so on), The Cochrane Library and Wiley Online Library were searched with the terms: "prenatal diagnosis," "CNV-seq," "karyotyping," published from January 2010 to May 2022. No language restrictions. RenMan 5.4 was used for the meta-analysis. Eight studies were included in this systemic review and meta-analysis, including 11 091 pregnant women with high-risk pregnancy factors or with structurally abnormal fetus under ultrasound. CNV-seq detected a 2% (95% CI, -0% to 4%) additional chromosomal anomalies over conventional karyotyping in the six series. A 4% (95% CI, 3%-6%) pooled mean incremental yield of pathogenic CNVs by CNV-seq over karyotyping was observed, with a 1%-16% range. CNV-seq, applied in prenatal diagnosis, may detect more chromosomal abnormalities when compared with karyotyping. With the advantages of wide coverage, high throughput, high resolution, no culture, good compatibility, and adjustable sequencing depth, CNV-seq has high application value in prenatal diagnosis.

Factors contributing to mortality in neonates with congenital diaphragmatic hernia and eventration.

Despite all the advances, the mortality rate of congenital diaphragmatic hernia (CDH) ranges from 30% to 60% for isolated CDH and as high as 89% when they are associated with additional structural or chromosomal anomalies. Hence, a study was conducted to evaluate the factors contributing to the mortality of neonates treated for CDH or the eventration of diaphragm. A retrospective study was conducted in the department of paediatric surgery at a tertiary centre. The neonates admitted with a diagnosis of CDH or eventration requiring surgery, between March 2013 and March 2021, were included in the study. A total of 123 neonates were included in the study. The variables, earlier median age at presentation (1 [1-23] vs. 3 [1-28]; P < 0.001; Mann-Whitney U-test), preterm birth (10/79 vs. 0/44; P = 0.01; Fischer's exact test), inborn (68/79 vs. 27/44; P = 0.002; Chi-square test), weight ≤2 kg (18/79 vs. 1/44; P = 0.003; Chi-square test), central cyanosis at presentation (21/79 vs. 1/44; P < 0.001; Chi-square test), antenatal detection (47/79 vs. 14/44; P = 0.003; Chi-square test) and earlier mean age at surgery (3.66 ± 1.47 vs. 7.66 ± 6.88; P < 0.001; Independent sample t-test) were associated with increased mortality. On multinominal logistic regression analysis, the factors preterm (odd's Ratio [OR] =4.735; P = 0.03), weight ≤2 kg (OR = 5.081; P = 0.02), central cyanosis at presentation (OR = 6.969; P = 0.008) and antenatal detection (OR = 7.471; P = 0.006) were found to be independently associated with increased mortality in CDH/eventration. The factors: prematurity, weight <2 kg, cyanosis at presentation and antenatal diagnosis were independently associated with increased mortality in neonates with CDH/eventration requiring surgery.

Trisomy 8 is Associated with Favorable Outcome in the Patients with Myelodysplastic Syndromes Treated with Allogeneic Hematopoietic Stem Cell Transplantation

Favorable prognostic significance of sole trisomy 8 and its associations with additional chromosome aberrations was confirmed in 7 adult and 3 pediatric patients with myelodysplastic syndromes treated with hematopoietic stem cell transplantation (HSCT). The group of comparison included 10 MDS patients with sole monosomy 7 or 5 chromosome and those within complex karyotypes (CK). Cytogenetic investigations were carried out according to standard GTG and multi-colored fluorescence in situ hybridization (mFISH) techniques. Our data revealed significant difference in overall survival (OS) between the tested and control groups (p=0.045) thus being additional argument reinforcing the concept of favorable prognosis of trisomy 8 in HSCT-treated MDS patients. Eight of ten patients (5 with sole trisomy 8 and three with more complex karyotypes) are alive. Of the deceased patients, one had CK trisomy 8 was associated with poor-prognostic monosomy 7. In accordance with experimental findings Sloand et al., 2007, this favorable effect of trisomy 8 in MDS patients might be linked with inhibition of programmed cell death with anti-apoptotic proteins, including myc, which are activated in these cases and needs additional in-depth studies.

I-FISH Guided Cytogenetic Study of Non-Hodgkin Lymphomas in Children and Adolescents: Correlation with Etiology and Outcome

Introduction: Pediatric non-Hodgkin lymphomas (NHLs) comprise approximately 10% of all childhood cancers. The diagnosis requires extensive workup with multiple ancillary studies. Genetic testing using fluorescence in situ hybridization (FISH) is a cytogenetic approach that is often utilized in pediatric NHL. Patients and Methods: Our study included 146 children (113 boys-33 girls), aged 0.33-17.8 years (median 9.16 years), with NHL diagnosis based on histopathology (table 1). The histological diagnosis was based on the complete microscopic and immunohistochemical study of infiltrated tissue. Touch imprints from the diagnostic biopsy samples were further investigated with i-FISH (table 2). Results: In all BL cases MYC gene rearrangement was identified. At least one additional chromosomal aberration was also found in 47 patients. Six hyperdiploid cases were identified among 72 children (8.3%), with at least 3 chromosomes involved. Interestingly, there were no cases of refractory disease, relapse, or death among hyperdiploid patients, and their overall survival (OS) was comparable to that of MYC rearrangement subgroup, a unique finding. Among LBL patients, a high frequency of 9p21 region deficiency was found, as in Acute Lymphoblastic Leukemia (ALL). Also, the chromosomes most frequently involved in hyperdiploid B-LBL (X,17,21) were identical to chromosomes commonly overrepresented in ALL. In contrast, the absence of cases positive for ETV6/RUNX1 hybrid gene is surprising. Possibly, the incidence of the most common cytogenetic atypias is different between leukemia and lymphoma. Of note, the two patients with KMT2A rearrangement achieved complete remission after first-line therapy. Finally, we identified cases with a normal karyotype but existing cytogenetic atypia demonstrable by i-FISH exclusively in LBLs. ALK gene rearrangement was found in all ALCL patients while no MYC gene rearrangement was found. At least one additional atypia was identified in 6/12 patients. Interestingly, ALCL patients had proportionally more recurrences than any other histological category, but without a corresponding increase in mortality. Among DLBCL group we found the highest rate of hyperdiploidy (22.2%). Only two (non-hyperdiploid) patients with BCL6 gene rearrangement were found. The single patient who relapsed had an IGL gene rearrangement, suggesting activation of an oncogene in the context of reciprocal chromosomal translocation involving the 22q11 region. No MYC or BCL2 gene rearrangements were found among DLBCL cases. In hyperdiploid patients, overrepresentation of chromosome 8 was found, along with overrepresentation of chromosome 3 (and, in addition, 18 in one of the two cases). This combination of atypias apparently leads to supernumerary copies of MYC gene, simultaneously with the presence of supernumerary alleles of BCL6 (or BCL2, respectively). Regarding findings in FL, MZL and PTLD, due to the small number of patients in these subgroups, any observation is of limited value. Absence of BCL2 gene rearrangement in childhood FL was confirmed. In the study's only patient with MZL, the identification of trisomy 3 may not be accidental, since this atypia is common in the corresponding adult disease. Of particular interest is the one patient with PTLD. Although monomorphic Burkitt-type PTLD was diagnosed and B-clonality documented based on VDJ recombination of IGH gene, marrow karyotyping and thorough i-FISH screening revealed no chromosomal atypia. The phenomenon has been highlighted in the literature and indicates that PTLD's aggressive clinical course is not necessarily associated with genomic instability and damage. In our study no patient met double-hit lymphoma criteria. We might wonder whether, in our series, the hyperdiploid patients with supernumerary copies of intact MYC, BCL2 and/or BCL6 genes constitute a subgroup of the "alternative" double hit lymphomas. With a median follow-up time of 61.5 months (range 7-123 months), 20 patients succumbed, yielding: 3-year and 5-year progression free survival (PFS) in all patients 84.5% και 82.5% respectively, and 3-year and 5-year OS in all patients 86.7%. Conclusions: This extensive i-FISH investigation provides clinically meaningful information on the genetic profile of NHLs, raises new questions, and points to directions for further investigation within the field of childhood lymphoproliferation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

PB1750: REARRANGEMENTS OF T-CELL RECEPTOR (TCR) LOCI IN CHILDREN WITH T-CELL ACUTE LYMPHOBLASTIC LEUKEMIA

Background: T-cell acute lymphoblastic leukemia (T-ALL) is a clinically and genetically heterogeneous disease that constitutes 10%–15% of newly diagnosed pediatric ALL cases and is caused by the accumulation of genetic abnormalities that alter the mechanisms controlling normal T-cell development. The most common structural aberrations involve rearrangements of the T-cell receptor (TCR) loci – TRA/TRD (14q11) and TRB (7q34), which are found in ~25% of patients. These aberrations are the main factors initiating the events in T-ALL carcinogenesis and juxtapose TCR genes and protooncogenes that encode pivotal transcription factors, leading to their aberrant expression. The outcomes of children with T-ALL significantly improved on intensified protocols, however, ~20% of patients relapse and die owing to acquired therapy resistance. Moreover, survivors also endure the acute and long-term effects of intensive toxic chemotherapy. Aims: To analyze TCR loci rearrangements and associated genetic abnormalities in children with T-ALL treated according to BFM-based protocols, and to correlate our findings with the clinical features and the treatment responses. Methods: The bone marrow samples of 66 children diagnosed between 1996-2017 (46 boys, 20 girls, age median 7.9 years, follow-up median 86.4 months) were analyzed with cytogenomic methods. For the detection of TCR loci rearrangements and other recurrent aberrations of the genes TLX3, CDKN2A/CDKN2B and ABL1 interphase FISH (DAKO, Abbott Molecular) was used. MLPA analysis with ALL-IKZF1 probemix (MRC-Holland) was performed to detect deletions/amplifications of additional genes. Complex karyotypes were analyzed with multicolor FISH (MetaSystems) or array CGH/SNP (Agilent). Differences in OS and EFS were assessed using Kaplan-Meier method and the Mantel-Cox test. Results: Rearrangements of TCR loci were detected in 18/66 (27%) patients. Translocations involving the TRA/TRD locus were demonstrated in nine children, the TRB locus in five and the simultaneous occurrence of these aberrations in two cases, respectively. In 10/18 patients, known recurrent chromosomal translocations affecting the oncogenes TAL1 (3x), LMO2 (3x), TLX1 (2x), TAL2 (1x) and MYC (1x) were identified. In the remaining cases, TCR rearrangements were cryptic or were a part of complex karyotype. Additional chromosomal aberrations were detected in all but one patient with the deletion of CDKN2A gene being the most frequent one. Immunophenotypic data classified the patients into cortical-T (12x) and mature-T (5x) groups (1x no data). Children with aberrations of TCR loci had a significantly better prognosis - EFS (p=0.011) and OS (p=0.0074), all patients are living in the first complete remission. Summary/Conclusion: Aberrations of T-cell receptors form a genetically heterogeneous group of rearrangements, leading to aberrant expression of oncogenes involved in T-cell maturation and proliferation. They mostly occur with abnormalities of genes involved in the regulation of the cell cycle and/or signaling pathways, confirming the multistep process of T-ALL pathogenesis. In our cohort, patients with TCR rearrangements had an excellent prognosis regardless of the presence of other aberrations. Although data on larger series are clearly required, we suppose, that these children could benefit from less-intensive therapy because they may experience fewer therapeutic consequences of toxic treatment. Supported by MH CZ-DRO-VFN64165.

Congenital Aneuploidy in Klinefelter Syndrome with B-Cell Acute Lymphoblastic Leukemia Might Be Associated with Chromosomal Instability and Reduced Telomere Length.

Simple SummaryKlinefelter syndrome (KS) is a rare congenital aneuploidy characterized by inherited gain of one X chromosome (XXY). KS is associated with higher susceptibility to the development of cancer. Somatic acquired chromosomal aberrations and chromosomal instability are hallmarks of cancer and leukemia but little is known about the cellular mechanisms involved. The conducted research aimed to identify genomic mechanisms involved in chromosomal evolution mechanisms important for leukemic development. In the leukemic blasts of a patient with KS and B-cell acute lymphoblastic leukemia (B-ALL), we identified additional acquired chromosomal aberration and a significant reduction in the length of the chromosomal ends, i.e., telomeres. A literature review of KS patients with B-ALL revealed that the majority of these patients had acquired two or more additional chromosomal aberrations at B-ALL diagnosis. These data indicate that enhanced reduction in telomere length might be associated with chromosomal instability and may serve as a future target for therapy or prevention.Rare congenital aneuploid conditions such as trisomy 13, trisomy 18, trisomy 21 and Klinefelter syndrome (KS, 47,XXY) are associated with higher susceptibility to developing cancer compared with euploid genomes. Aneuploidy frequently co-exists with chromosomal instability, which can be viewed as a “vicious cycle” where aneuploidy potentiates chromosomal instability, leading to further karyotype diversity, and in turn, paving the adaptive evolution of cancer. However, the relationship between congenital aneuploidy per se and tumor initiation and/or progression is not well understood. We used G-banding analysis, array comparative genomic hybridization analysis and quantitative fluorescence in situ hybridization for telomere length analysis to characterize the leukemic blasts of a three-year-old boy with KS and B-cell acute lymphoblastic leukemia (B-ALL), to gain insight into genomic evolution mechanisms in congenital aneuploidy and leukemic development. We found chromosomal instability and a significant reduction in telomere length in leukemic blasts when compared with the non-leukemic aneuploid cells. Reviewing published cases with KS and B-ALL revealed 20 additional cases with B-ALL diagnostic cytogenetics. Including our present case, 67.7% (14/21) had acquired two or more additional chromosomal aberrations at B-ALL diagnosis. The presented data indicate that congenital aneuploidy in B-ALL might be associated with chromosomal instability, which may be fueled by enhanced telomere attrition.

Evolution of severe (transfusion-dependent) anaemia in myelodysplastic syndromes with 5q deletion is characterized by a macrophage-associated failure of the eythropoietic niche.

Evolution of erythrocyte transfusion-dependent (RBC-TD) anaemia associated with haploinsufficiency of the ribosomal protein subunit S14 gene (RPS14) is a characteristic complication of myelodysplastic syndromes (MDS) with del(5q) [MDS.del(5q)]. Evaluating 39 patients with MDS.del(5q), <5% of anaemia progression was attributable to RPS14-dependent alterations of normoblasts, pro-erythroblasts, or CD34+ CD71+ precursors. Ninety-three percent of anaemia progression and 70% of the absolute decline in peripheral blood Hb value were attributable to disappearance of erythroblastic islands (Ery-Is). Ery-Is loss occurred independently of blast excess, TP53 mutation, additional chromosome aberrations and RPS14-dependent alterations of normoblasts and pro-erythroblasts. It was associated with RPS14-dependent intrinsic (S100A8+ ) and extrinsic [tumour necrosis factor α (TNF-α)-overproduction] alterations of (CD169+ ) marrow macrophages (p<0.00005). In a mouse model of RPS14 haploinsufficiency, Ery-Is disappeared to a similar degree: approximately 70% of Ery-Is loss was related to RPS14-dependent S100A8 overexpression of marrow macrophages, less than 20% to that of CD71high Ter119- immature precursors, and less than 5% to S100A8/p53 overexpression of normoblasts or pro-erythroblasts. Marked Ery-Is loss predicted reduced efficacy (erythrocyte transfusion independence) of lenalidomide therapy (p=0.0006). Thus, erythroid hypoplasia, a characteristic complication of MDS.del(5q), seems to result primarily from a macrophage-associated failure of the erythropoietic niche markedly reducing the productive capacity of erythropoiesis as the leading factor in anaemia progression and evolution of RBC-TD in MDS.del(5q).

The Cytogenetic Landscape of Pediatric Chronic Myeloid Leukemia Diagnosed in Chronic Phase.

Simple SummaryPhiladelphia chromosome-positive chronic myeloid leukemia (CML) is characterized by the translocation of the chromosomes 9 and 22. Additional non-Philadelphia aberrations of chromosomes (nPhAs) and their prognostic relevance for the disease course are comparably well known in adult patients with CML. However, due to the rarity of CML in children and adolescents, nPhAs have hardly been determined systematically in these age groups. Here, we present a large analysis of nPhAs detected in a cohort of 161 patients younger than 18 years who had been diagnosed with CML in chronic phase and enrolled in the German national CML-PAED-II registry. We found a distinct distribution of nPhAs in this pediatric cohort with possible impact on treatment response whereas the survival remained unaffected. Our findings emphasize differences in the disease biology between pediatric and adult patients and prompt further joint international efforts to acquire more data on the disease in this age group.Philadelphia chromosome-positive chronic myeloid leukemia (CML) is cytogenetically characterized by the classic translocation t(9;22)(q34;q11), whereas additional non-Philadelphia aberrations (nPhAs) have been studied extensively in adult patients with CML, knowledge on nPhAs in pediatric patients with CML is still sparse. Here, we have determined nPhAs in a cohort of 161 patients younger than 18 years diagnosed with chronic phase CML and consecutively enrolled in the German national CML-PAED-II registry. In 150 cases (93%), an informative cytogenetic analysis had been performed at diagnosis. In total, 21 individuals (13%) showed nPhAs. Of these, 12 (8%) had a variant translocation, 4 (3%) additional chromosomal aberrations (ACAs) and 5 (3%) harbored a complex karyotype. Chromosome 15 was recurrently involved in variant translocations. No significant impact of the cytogenetic subgroup on the time point of cytogenetic response was observed. Patients with a complex karyotype showed an inferior molecular response compared to patients carrying the classic translocation t(9;22)(q34;q11), variant translocations or ACAs. No significant differences in the probability of progression-free survival and overall survival was found between patients with nPhAs and patients with the classic Philadelphia translocation only. Our results highlight the distinct biology of pediatric CML and underline the need for joint international efforts to acquire more data on the disease pathogenesis in this age group.

FISH-Guided Evaluation of Hyperdiploidy and Other Cytogenetic Abnormalities in Childhood Burkitt Lymphoma

Background: Burkitt lymphoma (BL) is the most common lymphoma in childhood. Apart from MYC rearrangement, considered the hallmark of the disease, BL often presents with additional chromosome aberrations, the biological and clinical significance of which is not fully understood. Materials and methods: The study included 72 children (55 boys, 17 girls), aged 2-16 years (median 9), with BL diagnosed on the basis of histopathology and a demonstrable MYC rearrangement. Touch imprints from the diagnostic biopsy samples were investigated with i-FISH for MYC, BCL2, BCL6, IGH, IGK and IGL rearrangements genes and copy number aberrations involving 1q21/1p32, 7cen/7q31, 9cen/9p21, 13q14/13q34 and 17cen/17p13. Deviations from the diploid status were further investigated for aneusomies of the carrier chromosome with the use of appropriate chromosome enumeration probes. Results: MYC gene was demonstrated in all cases with MYC/IGH fusion in 83.3% (60/72). 47 cases (65.3%) were found with least one additional aberration, most commonly with 1q gain (29.2%), 7q gain (19.4%), 13q deletion (19.4%), hemizygous 9p loss (8.3%) and hyperdiploidy (8.3%). Advanced clinical stage (IV), 7q gain (but not trisomy 7) and -9/9p- were significantly associated with shorter overall survival. There was no instance of relapse or death among the hyperdiploid cases. Conclusions: This extensive FISH investigation on imprints of affected tissue provides clinically meaningful information on the genetic profile of BL and may prove valuable in the management of patients with no karyotype available. In particular, the demonstration of hyperdiploidy through the use of chromosome enumeration probes could offer the means for the delineation of clonal evolution pathways and the recognition of a subgroup of children with excellent prognosis who could be cured with low-intensity chemotherapy regimens. DisclosuresKattamis: VIFOR: Consultancy; CRISPR/Vertex: Consultancy, Honoraria; Agios Pharmaceuticals: Consultancy; IONIS: Consultancy; BMS/Celgene: Consultancy, Honoraria, Research Funding; Chiesi: Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy.

P-128: Accompanying with additional complex karyotype is a poor prognostic factor in patients with multiple myeloma with high-risk cytogenetics in the era of novel agents

<h3>Background</h3> High-risk cytogenetic abnormality (CA) influences the prognosis of multiple myeloma (MM) even in the era of novel agents. However, prognostic heterogeneity could exist in MM patients with high-risk CA and additional cytogenetic aberrations are possibly correlated with worse outcomes. We conducted a retrospective study in patients with MM with high-risk CA to evaluate whether the outcomes are different in each high-risk group and whether the existence of additional chromosomal abnormalities would lead to poor outcomes. <h3>Method</h3> Patients with newly diagnosed MM (NDMM) in our institute between February 2006 and December 2020 were enrolled in this retrospective cohort. We analyzed only patients who were treated with novel agents including proteasome inhibitor and/or immunomodulatory drugs. All of cytogenetic abnormalities were analyzed from bone marrow samples. In this cohort, we defined high-risk CA as del(17p), t(4;14), t(14;16), and/or 1q21 gain, all of which were identified using FISH analysis. We surveyed additional chromosomal aberrations using G-banding testing. Complex chromosomal abnormality was defined as three or more chromosomal aberrations accompanying with at least one structural aberration. The survival was calculated by the Kaplan Meier method, and statistical analysis was performed by the Log-rank test. Factors affecting OS and PFS were evaluated using Cox proportional hazard model. <h3>Results</h3> We analyzed 36 MM patients who had high-risk CA at initial diagnosis. Twelve patients had del(17p), 16 had t(4;14), four had 1q21 gain, and four had more than one high-risk CA; two patients with t(4;14) and 1q21 gain, one with del(17p) and 1q21 gain and one with del(17p), t(4;14), and 1q21 gain. G-banding testing showed that patterns of complex chromosomal abnormality were found in nine patients. No significant differences in progression-free survival (PFS) and overall survival (OS) were seen between each high-risk CA group. The tendency of shorter PFS and OS was observed in patients with concurrent complex chromosomal karyotype than patients with no additional chromosomal aberrations. Furthermore, we found that the existence of complex cytogenetic abnormality by G-banding was correlated with poor PFS by multivariate analysis (hazard ratio 4.01, 95% confidence interval 1.35–11.9, p=0.012). In addition, seven of nine MM patients with complex chromosomal karyotype had concurrent plasmacytoma. <h3>Conclusion</h3> Although the limitation of retrospective study design and the small sample size exists, our findings indicate that the coexistence of complex chromosomal abnormality, probably which reflects aggressive disease status like extraosseous or extramedullary disease, could be associated with poor prognoses of MM patients with high-risk CA.