Effect of American genomic ancestry on severe toxicities in children with acute lymphoblastic leukemia in the Amazon region.

BACKGROUND: Acute Lymphoblastic Leukemia (ALL) is a neoplasm of the hematopoietic system characterized by a clonal expansion of abnormal lymphocyte precursor cells. ALL is the most common form of cancer in children, but despite advances in treatment, it can still be fatal. Ethnic differences influence survival rates, and genomic ancestry plays an important role, especially in mixed-race populations such as Latin America. This study aims to analyze the influence of genomic ancestry on toxicity in children with ALL in the Amazon region. METHODS: The study included 171 patients (protocol number 119,649/2012-Ethics Committee) with ALL treated at a pediatric treatment center in Belém do Pará, in the Brazilian Amazon. The patients were submitted to the BFM protocol of induction therapy for ALL. Toxicity was assessed based on laboratory tests and adverse events, classified according to the CTC-NCI guide. Genomic ancestry was determined using autosomal informative markers. RESULTS: The majority of children (94.74%) developed some type of toxicity during treatment, 87.04% of which were severe. Infectious toxicity was the most common, present in 84.8% of cases, 77.24% of which were severe. Amerindian ancestry showed an association with the risk of severe general toxicity and severe infectious toxicity, with a contribution of 35.0% demonstrating a significant increase in risk. In addition, post-induction refractoriness and relapse were also associated with an increased risk of death. CONCLUSION: This study highlights the influence of Amerindian genomic ancestry on response to therapy and toxicity in children with ALL in the Amazon region. Understanding these associations can contribute to personalizing treatment and improving clinical outcomes.

Influence of Genetic Variations in miRNA and Genes Encoding Proteins in the miRNA Synthesis Complex on Toxicity of the Treatment of Pediatric B-Cell ALL in the Brazilian Amazon.

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer in the world. Single nucleotide variants (SNVs) in miRNA and genes encoding proteins of the miRNA synthesis complex (SC) may affect the processing of drugs used in the treatment of ALL, resulting in treatment-related toxicities (TRTs). We investigated the role of 25 SNVs in microRNA genes and genes encoding proteins of the miRNA SC, in 77 patients treated for ALL-B from the Brazilian Amazon. The 25 SNVs were investigated using the TaqMan® OpenArray™ Genotyping System. SNVs rs2292832 (MIR149), rs2043556 (MIR605), and rs10505168 (MIR2053) were associated with an increased risk of developing Neurological Toxicity, while rs2505901 (MIR938) was associated with protection from this toxicity. MIR2053 (rs10505168) and MIR323B (rs56103835) were associated with protection from gastrointestinal toxicity, while DROSHA (rs639174) increased the risk of development. The rs2043556 (MIR605) variant was related to protection from infectious toxicity. SNVs rs12904 (MIR200C), rs3746444 (MIR499A), and rs10739971 (MIRLET7A1) were associated with a lower risk for severe hematologic toxicity during ALL treatment. These findings reveal the potential for the use of these genetic variants to understand the development of toxicities related to the treatment of ALL in patients from the Brazilian Amazon region.

Correlation of Genetic Variants and the Incidence, Prevalence and Mortality Rates of Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) is the most common cancer during childhood, representing about 30-35% of cases. Its etiology is complex and not fully understood. ALL is influenced by genetic variants, and their frequencies (Fq) vary in different ethnic groups, which consequently could influence the epidemiology of this cancer worldwide. The aim of this study was to investigate the correlation between the genetic variants and their impacts on incidence (IC), mortality (MT), and prevalence (PV) rates of ALL in different world populations. METHODS: Sixty variants were selected from the literature with Genome Wide Association studies (GWAS). Information regarding allele Fq was selected from the 1000 Genomes platform. Epidemiological data were taken from the Global Burden of disease visualisations (GBD) Compare website. Statistical analyses were calculated in RStudio v.3.5.1 software. RESULTS: Four variants demonstrated significant results in correlations with epidemiological data for ALL. The PAX5 gene variant (rs2297105) had an indirect relationship with PV and IC of ALL, showing that an increased Fq of this variant is related to low rates of both. An increased Fq of rs915172 in EPB4IL2 gene was also correlated with a lower IC of ALL. The rs1048943 of the CYP1A1 gene and the rs3088440 polymorphism of the CDKN2A gene were shown to have a direct proportional relationship with MT rate, showing that an increased Fq of these variants correlates with a worse prognosis worldwide. CONCLUSION: Our study points out four important variants for understanding the IC, PV, and MT rates for ALL. The ascertainment of these data may help to choose molecular markers to investigate the susceptibility and prognosis of ALL.

Telomerase (hTERT) Overexpression Reveals a Promising Prognostic Biomarker and Therapeutical Target in Different Clinical Subtypes of Pediatric Acute Lymphoblastic Leukaemia.

Acute Lymphoblastic Leukemia (ALL) is a neoplasm of the hematopoietic system defined as a clonal expansion of an abnormal lymphoid precursor cell. It mostly affects children under five years of age and is the most common tumor to afflict pediatric patients. The expression of the human telomerase gene (hTERT) in patients with ALL has been studied as a biomarker and could become a new therapeutic target. We evaluate the role of hTERT gene expression in ALL pediatric patients, through quantitative real-time PCR technique, and the possible correlation between hTERT expression and clinical variables: gender, age, white blood cells (WBC), gene fusions, and immunophenotyping. The analysis between healthy controls and ALL patients (N = 244) was statistically significant (p < 0.001), demonstrating hTERT overexpression in these patients. In comparison with the usual set of clinical variables, the data were not statistically significant (p > 0.05), indicating that hTERT is equally overexpressed among patients regardless of gender, age, gene fusions, and immunophenotyping. Moreover, patients who presented a higher hTERT expression level had a significant (p < 0.0001) lower overall survival rate. In summary, hTERT expression emerges as an important molecular pathway in leukemogenesis regardless patient's clinical variables, thus, the data here presented pointed it as a valuable biomarker in pediatric acute lymphoblastic leukemia and a promising target for new therapeutic and prognostic measures.

Performance of PRISM III and PIM 2 scores in a cancer pediatric intensive care unit. / Desempenho do PRISM III e do PIM 2 em unidade de terapia intensiva pediátrica oncológica.

OBJECTIVE: To assess the performance of Pediatric Risk of Mortality (PRISM) III and Pediatric Index of Mortality (PIM) 2 scores in the pediatric intensive care unit. METHODS: A retrospective cohort study. Data were retrospectively collected from medical records of all patients admitted to the pediatric intensive care unit of a cancer hospital from January 2017 to June 2018. RESULTS: The mean PRISM III score was 15, and PIM 2, 24%. From the 338 studied patients, 62 (18.34%) died. The PRISM III estimated mortality was 79.52 patients (23.52%) and for PIM 2 80.19 patients (23.72%), corresponding to a standardized mortality ratio (95% confidence interval: 0.78 for PRISM II and 0.77 for PIM 2). The Hosmer-Lemeshow chi-square test was 11.56, 8df, 0.975 for PRISM II and 0.48, 8df, p = 0.999 for PIM 2. The area under the Receiver Operating Characteristic curve was 0.71 for PRISM III and 0.76 for PIM 2. CONCLUSION: Both scores overestimated mortality and have shown a regular ability to discriminate between survivors and non-survivors. Models should be developed to quantify the severity of cancer pediatric patients in Pediatric Intensive Care Units and to predict the mortality risk accounting for their peculiarities.

OBJETIVO: Avaliar o desempenho do Pediatric Risk of Mortality (PRISM) III e do Pediatric Index of Mortality (PIM) 2 em unidade de terapia intensiva pediátrica. MÉTODOS: Estudo de coorte retrospectivo. Os dados retrospectivos foram coletados dos prontuários de todos os pacientes admitidos na unidade de terapia intensiva pediátrica de um hospital infantil oncológico, entre janeiro de 2017 a junho de 2018. RESULTADOS: A média do PRISM III foi de 15 e do PIM 2 de 24%. Dos 338 pacientes estudados, 62 (18,34%) morreram. A mortalidade estimada pelo PRISM III foi de 79,52 (23,52%) e pelo PIM 2 de 80,19 (23,72%) pacientes, correspondendo a taxa padronizada de mortalidade (intervalo de confiança de 95%) de 0,78 para o PRISM II e 0,77 para o PIM 2. O teste de ajuste de Hosmer-Lemeshow obteve qui-quadrado de 11,56, 8df, com p = 0,975, para PRISM III, e qui-quadrado de 0,48, 8df, p = 0,999, para o PIM 2. Foi obtida área sob a curva Característica de Operação do Receptor de 0,71 para o PRISM III e 0,76 para o PIM 2. CONCLUSÃO: Os dois escores superestimaram a mortalidade e demonstraram poder regular de discriminação entre sobreviventes e não sobreviventes. Devem ser desenvolvidos modelos para quantificar a gravidade de pacientes pediátricos com câncer em unidade de terapia intensiva pediátrica e predizer o risco de mortalidade que contemplem suas peculiaridades.

Desempenho do PRISM III e do PIM 2 em unidade de terapia intensiva pediátrica oncológica / Performance of PRISM III and PIM 2 scores in a cancer pediatric intensive care unit

RESUMO Objetivo: Avaliar o desempenho do Pediatric Risk of Mortality (PRISM) III e do Pediatric Index of Mortality (PIM) 2 em unidade de terapia intensiva pediátrica. Métodos: Estudo de coorte retrospectivo. Os dados retrospectivos foram coletados dos prontuários de todos os pacientes admitidos na unidade de terapia intensiva pediátrica de um hospital infantil oncológico, entre janeiro de 2017 a junho de 2018. Resultados: A média do PRISM III foi de 15 e do PIM 2 de 24%. Dos 338 pacientes estudados, 62 (18,34%) morreram. A mortalidade estimada pelo PRISM III foi de 79,52 (23,52%) e pelo PIM 2 de 80,19 (23,72%) pacientes, correspondendo a taxa padronizada de mortalidade (intervalo de confiança de 95%) de 0,78 para o PRISM II e 0,77 para o PIM 2. O teste de ajuste de Hosmer-Lemeshow obteve qui-quadrado de 11,56, 8df, com p = 0,975, para PRISM III, e qui-quadrado de 0,48, 8df, p = 0,999, para o PIM 2. Foi obtida área sob a curva Característica de Operação do Receptor de 0,71 para o PRISM III e 0,76 para o PIM 2. Conclusão: Os dois escores superestimaram a mortalidade e demonstraram poder regular de discriminação entre sobreviventes e não sobreviventes. Devem ser desenvolvidos modelos para quantificar a gravidade de pacientes pediátricos com câncer em unidade de terapia intensiva pediátrica e predizer o risco de mortalidade que contemplem suas peculiaridades.

ABSTRACT Objective: To assess the performance of Pediatric Risk of Mortality (PRISM) III and Pediatric Index of Mortality (PIM) 2 scores in the pediatric intensive care unit. Methods: A retrospective cohort study. Data were retrospectively collected from medical records of all patients admitted to the pediatric intensive care unit of a cancer hospital from January 2017 to June 2018. Results: The mean PRISM III score was 15, and PIM 2, 24%. From the 338 studied patients, 62 (18.34%) died. The PRISM III estimated mortality was 79.52 patients (23.52%) and for PIM 2 80.19 patients (23.72%), corresponding to a standardized mortality ratio (95% confidence interval: 0.78 for PRISM II and 0.77 for PIM 2). The Hosmer-Lemeshow chi-square test was 11.56, 8df, 0.975 for PRISM II and 0.48, 8df, p = 0.999 for PIM 2. The area under the Receiver Operating Characteristic curve was 0.71 for PRISM III and 0.76 for PIM 2. Conclusion: Both scores overestimated mortality and have shown a regular ability to discriminate between survivors and non-survivors. Models should be developed to quantify the severity of cancer pediatric patients in Pediatric Intensive Care Units and to predict the mortality risk accounting for their peculiarities.

Targeting aurora kinases as a potential prognostic and therapeutical biomarkers in pediatric acute lymphoblastic leukaemia.

Aurora kinases (AURKA and AURKB) are mitotic kinases with an important role in the regulation of several mitotic events, and in hematological malignancies, AURKA and AURKB hyperexpression are found in patients with cytogenetic abnormalities presenting a unfavorable prognosis. The aim of this study was evaluated the mRNA expression profile of pediatric Acute Lymphoblastic Leukaemia (ALL) patients and the efficacy of two AURKA and AURKB designed inhibitors (GW809897X and GW806742X) in a leukemia cell line as a potential novel therapy for ALL patients. Cellular experiments demonstrated that both inhibitors induced cell death with caspase activation and cell cycle arrest, however only the GW806742X inhibitor decreased with more efficacy AURKA and AURKB expression in K-562 leukemia cells. In ALL patients both AURKA and AURKB showed a significant overexpression, when compared to health controls. Moreover, AURKB expression level was significant higher than AURKA in patients, and predicted a poorer prognosis with significantly lower survival rates. No differences were found in AURKA and AURKB expression between gene fusions, immunophenotypic groups, white blood cells count, gender or age. In summary, the results in this study indicates that the AURKA and AURKB overexpression are important findings in pediatric ALL, and designed inhibitor, GW806742X tested in vitro were able to effectively inhibit the gene expression of both aurora kinases and induce apoptosis in K-562 cells, however our data clearly shown that AURKB proves to be a singular finding and potential prognostic biomarker that may be used as a promising therapeutic target to those patients.

Identifying novel genetic alterations in pediatric acute lymphoblastic leukemia based on copy number analysis.

Copy number variations (CNVs) analysis may reveal molecular biomarkers and provide information on the pathogenesis of acute lymphoblastic leukemia (ALL). We investigated the gene copy number in childhood ALL by microarray and select three new recurrent CNVs to evaluate by real-time PCR assay: DMBT1, KIAA0125 and PRDM16 were selected due to high frequency of CNVs in ALL samples and based on their potential biological functions in carcinogenesis described in the literature. DBMT1 deletion was associated with patients with chromosomal translocations and is a potential tumor suppressor; KIAA0125 and PRDM16 may act as an oncogene despite having a paradoxical behavior in carcinogenesis. This study reinforces that microarrays/aCGH is it is a powerful tool for detection of genomic aberrations, which may be used in the risk stratification.

Characterization of pharmacogenetic markers related to Acute Lymphoblastic Leukemia toxicity in Amazonian native Americans population.

Acute Lymphoblastic Leukemia (ALL) is the most common cancer in children. Differences are found among ethnic groups in the results of the treatment of pediatric ALL. In general, children with a high level of native American ancestry tend to respond less positively to ALL treatments, which may be related to specific genomic variants found in native American groups. Despite the evidence, few data are available on the distribution of the pharmacogenomic variants relevant to the treatment of ALL in traditional Amerindian populations, such the those of the Amazon region. Given this, the present study investigated 27 molecular markers related to the treatment of ALL in Amerindians from Brazilian Amazonia and compared the frequencies with those recorded previously on five continents, that are available in the 1,000 Genomes database. The variation in the genotype frequencies among populations was evaluated using Fisher's exact test. The False Discovery Rate method was used to correct the results of the multiple analyses. Significant differences were found in the frequencies of the majority of markers between the Amerindian populations and those of other regions around the world. These findings highlight the unique genetic profile of the indigenous population of Brazilian Amazonia, which may reflect a distinct therapeutic profile for the treatment of ALL in these populations.

Identification of NUDT15 gene variants in Amazonian Amerindians and admixed individuals from northern Brazil.

INTRODUCTION: The nudix hydrolase 15 (NUDT15) gene acts in the metabolism of thiopurine, by catabolizing its active metabolite thioguanosine triphosphate into its inactivated form, thioguanosine monophosphate. The frequency of alternative NUDT15 alleles, in particular those that cause a drastic loss of gene function, varies widely among geographically distinct populations. In the general population of northern Brazilian, high toxicity rates (65%) have been recorded in patients treated with the standard protocol for acute lymphoblastic leukemia, which involves thiopurine-based drugs. The present study characterized the molecular profile of the coding region of the NUDT15 gene in two groups, non-admixed Amerindians and admixed individuals from the Amazon region of northern Brazil. METHODS: The entire NUDT15 gene was sequenced in 64 Amerindians from 12 Amazonian groups and 82 admixed individuals from northern Brazil. The DNA was extracted using phenol-chloroform. The exome libraries were prepared using the Nextera Rapid Capture Exome (Illumina) and SureSelect Human All Exon V6 (Agilent) kits. The allelic variants were annotated in the ViVa® (Viewer of Variants) software. RESULTS: Four NUDT15 variants were identified: rs374594155, rs1272632214, rs147390019, andrs116855232. The variants rs1272632214 and rs116855232 were in complete linkage disequilibrium, and were assigned to the NUDT15*2 genotype. These variants had high frequencies in both our study populations in comparison with other populations catalogued in the 1000 Genomes database. We also identified the NUDT15*4 haplotype in our study populations, at frequencies similar to those reported in other populations from around the world. CONCLUSION: Our findings indicate that Amerindian and admixed populations from northern Brazil have high frequencies of the NUDT15 haplotypes that alter the metabolism profile of thiopurines.

Association of genes ARID5B, CEBPE and folate pathway with acute lymphoblastic leukemia in a population from the Brazilian Amazon region.

Acute Lymphoblastic Leukemia (ALL) is the most common childhood neoplasia. Studies have shown that susceptibility to ALL may be modulated by genetic variables. Our study investigated 21 genetic variants in the susceptibility of the population of the Brazilian Amazon region to B-cell ALL. The variants of the genes GGH, CEBPE, ARID5B, MTHFR and MTHFD1 were related to a protective effect against the development of ALL, whereas the variant of the gene ATIC was associated with a risk effect. The results suggest that genetic variants analyzed modulate of the risk of developing ALL in the studied population.

Pharmacogenomics and variations in the risk of toxicity during the consolidation/maintenance phases of the treatment of pediatric B-cell leukemia patients from an admixed population in the Brazilian Amazon.

The treatment of Acute Lymphoblastic Leukemia (ALL) in children has a high clinical success rate, although toxicological complications are frequent, and often result in the interruption of the treatment. Various studies have shown that toxicities resulting from the treatment are influenced by pharmacogenetic variants. Most of this research has focused on relatively homogeneous populations, and the influence of these variants in highly admixed populations, such as that of Brazil, is still poorly understood. The present study investigated the association between pharmacogenetic variants and severe toxicities in pediatric B-cell ALL patients from an admixed population of the Brazilian Amazon. The rs2306283 (of SLCO1B1) mutant allele increased the risk of neurotoxicity threefold, and the homozygous mutant rs9895420 (of ABCC3) genotype was associated with a fivefold increase in protection against severe gastrointestinal toxicity. This indicates that the rs2306283 and rs9895420 polymorphisms may be relevant to the prediction of severe toxicity in pediatric ALL patients.