Acute lymphoblastic leukemia mortality in Hispanic Americans

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.

Implementation of a roadmap for the comprehensive diagnosis, follow-up, and research of childhood leukemias in vulnerable regions of Mexico: results from the PRONAII Strategy

The main objective of the National Project for Research and Incidence of Childhood Leukemias is to reduce early mortality rates for these neoplasms in the vulnerable regions of Mexico. This project was conducted in the states of Oaxaca, Puebla, and Tlaxcala. A key strategy of the project is the implementation of an effective roadmap to ensure that leukemia patients are the target of maximum benefit of interdisciplinary collaboration between researchers, clinicians, surveyors, and laboratories. This strategy guarantees the comprehensive management of diagnosis and follow-up samples of pediatric patients with leukemia, centralizing, managing, and analyzing the information collected. Additionally, it allows for a precise diagnosis and monitoring of the disease through immunophenotype and measurable residual disease (MRD) studies, enhancing research and supporting informed clinical decisions for the first time in these regions through a population-based study. This initiative has significantly improved the diagnostic capacity of leukemia in girls, boys, and adolescents in the regions of Oaxaca, Puebla, and Tlaxcala, providing comprehensive, high-quality care with full coverage in the region. Likewise, it has strengthened collaboration between health institutions, researchers, and professionals in the sector, which contributes to reducing the impact of the disease on the community.

The genetic risk of acute lymphoblastic leukemia and its implications for children of Latin American origin

Acute lymphoblastic leukemia (ALL) is the most common cancer in children, and disproportionately affects children of Hispanic/Latino ethnicity in the United States, who have the highest incidence of disease compared with other racial/ethnic groups. Incidence of childhood ALL is similarly high in several Latin American countries, notably in Mexico, and of concern is the rising incidence of childhood ALL in some Hispanic/Latino populations that may further widen this disparity. Prior studies have implicated common germline genetic variants in the increased risk of ALL among Hispanic/Latino children. In this review, we describe the known disparities in ALL incidence as well as patient outcomes that disproportionately affect Hispanic/Latino children across the Americas, and we focus on the role of genetic variation as well as Indigenous American ancestry in the etiology of these disparities. Finally, we discuss future avenues of research to further our understanding of the causes of the disparities in ALL incidence and outcomes in children of Latin American origin, which will be required for future precision prevention efforts.

Epidemiological and clinical characteristics of adult acute lymphoblastic leukemia patients in Chile: A single-center analysis

Background

Acute lymphoblastic leukemia represents 20% of acute leukemias in adults. Currently, there is limited data in Chile regarding the clinical, cytogenetic, and prognostic characteristics of this condition.

Methods

This is a retrospective, observational, and descriptive study of 67 patients treated for acute lymphoblastic leukemia at the Arturo Lopez Perez Foundation between 2018 and 2021. The main objective is to evaluate epidemiological and clinical characteristics, as well as identifying factors associated with improved overall survival and/or progression-free survival.

Results

88% of the cases were B-lineage, mainly the common B phenotype. Cytogenetic analysis was performed in less than 50% of the patients, with lower yield than expected according to the literature. Molecular testing was performed in 86.5% of the patients, with the most frequent alteration being BCR-ABL. No study was performed to search for Ph-like abnormalities. The rate of complete response after induction was 83.3%, the majority of patients having negative minimal residual disease. Only 12% of the patients received consolidation with allogenic bone marrow transplant. At 2 years, the overall survival was 69% and the progression-free survival was 59%.

Conclusion

The results in terms of overall survival and progression-free survival are similar to those reported in the literature. Important diagnostic gaps prevent adequate prognostic characterization. Allogeneic consolidation transplantation was performed in a lower percentage than expected, highlighting the national deficit in access to this treatment.

Comprehensive characterization of patient-derived xenograft models of pediatric leukemia

Patient-derived xenografts (PDX) remain valuable models for understanding the biology and for developing novel therapeutics. To expand current PDX models of childhood leukemia, we have developed new PDX models from Hispanic patients, a subgroup with a poorer overall outcome. Of 117 primary leukemia samples obtained, successful engraftment and serial passage in mice were achieved in 82 samples (70%). Hispanic patient samples engrafted at a rate (51/73, 70%) that was similar to non-Hispanic patient samples (31/45, 70%). With a new algorithm to remove mouse contamination in multi-omics datasets including methylation data, we found PDX models faithfully reflected somatic mutations, copy-number alterations, RNA expression, gene fusions, whole-genome methylation patterns, and immunophenotypes found in primary tumor (PT) samples in the first 50 reported here. This cohort of characterized PDX childhood leukemias represents a valuable resource in that germline DNA sequencing has allowed the unambiguous determination of somatic mutations in both PT and PDX.

A modified CALGB 10403 in adolescents and young adults with acute lymphoblastic leukemia in Central America

Mexico and Central America have a high incidence of acute lymphoblastic leukemia (ALL) in adolescents and young adults. Historically, this patient group has been treated using adult-based regimens, which entails a high rate of treatment-related mortality and a poor overall survival (OS). The use of the CALGB 10403, a pediatric-inspired regimen, has been proven effective in this patient subgroup. Nonetheless, low- and middle-income countries (LMICs) may present limited access to standard care treatments implemented elsewhere, warranting the need for further research to improve outcomes among vulnerable populations. In this study, we present the outcomes in terms of safety and effectiveness of using a modified CALGB 10403 regimen to reflect drug and resource availability in LMICs. Modifications included the use of Escherichia coli asparaginase,6-mercaptopurine instead of thioguanine and the use of rituximab among patients with CD20+. A total of 95 patients with a median age of 23 (range, 14-49) years treated with this modified scheme were prospectively assessed at 5 centers in Mexico and 1 in Guatemala. Among these, 87.8% achieved a complete response after induction. During follow-up, 28.3% of patients relapsed. Two-year OS rate was 72.1%. Factors associated with worse OS included hyperleukocytosis (hazard ratio [HR], 4.28; 95% confidence interval [CI], 1.81-10.10) and postinduction minimal residual disease (HR, 4.67; 95% CI, 1.75-12.44). Most patients presented hepatotoxicity (51.6% and 53.7% during induction and consolidation, respectively), and the treatment-related mortality was 9.5%. Overall, results highlight that implementing a modified CALGB 10403 regimen in Central America is feasible, and it is associated with improvements in clinical outcomes and a manageable safety profile.

Association of cesarean section with risk of childhood leukemia: A meta-analysis from an observational study

Recent studies suggest that children born via cesarean section (CS) are predisposed to immune-mediated diseases later in life. The association between CS and childhood leukemia was investigated in this meta-analysis of observational studies. Two researchers independently searched PubMed, Web of Science, Embase, and Cochrane Library for literature on the association between CS and childhood leukemia before February 2022. And pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated to determine the link between CS and childhood leukemia. The preliminary search resulted in 1321 articles and 16 articles were finally included after screening. The primary outcome was the risk of leukemia in children born via CS versus those born vaginally. The results revealed that having a CS was associated with an increased risk of childhood leukemia compared to having vaginal section (VS) (OR = 1.07, 95% CI: 1.02-1.13, p = 0.01), especially for acute lymphoblastic leukemia (ALL) (OR = 1.09, 95% CI: 1.03-1.16, p = 0.004). Children delivered via elective CS had a higher risk of ALL (OR = 1.18, 95% CI: 1.07-1.31, p = 0.001), but emergency CS did not. It is worth noting that neither emergency CS nor elective CS were found to be associated with acute myeloid leukemia. Compared to VS, CS increased the risk of leukemia in children, with elective CS significantly increasing ALL risk.

Asparaginase toxicity in Hispanic adult and pediatric patients with acute lymphoblastic leukemia: current understanding

INTRODUCTION

Asparaginase is essential to chemotherapy regimens for acute lymphoblastic leukemia (ALL). Survival of patients with ALL has improved since incorporating asparaginase into chemotherapy backbones. Hispanic patients have a higher incidence of ALL than other ethnicities and suffer inferior outcomes. The inferior outcome of Hispanics is due to several factors, including the increased incidence of high-risk genetic subtypes and susceptibility to treatment-related toxicity.

AREAS COVERED

We summarize the current knowledge of asparaginase-related toxicity by comparing their incidence between Hispanic and non-Hispanic patients. These toxicities include hypersensitivity, hepatotoxicity, pancreatitis, thrombosis, and hypertriglyceridemia. The PubMed database and Google Scholar were used to search for this review from October 2022 to June 2023.

EXPERT OPINION

Except for hepatotoxicity and hypertriglyceridemia secondary to asparaginase-based treatments, which may develop more frequently among Hispanic patients with ALL, other toxicities were comparable between Hispanic and non-Hispanic patients. Nevertheless, studies with larger cohorts and more accurate capturing of Hispanic ethnicity should be conducted to fill the gaps in the current knowledge.

Mucin (MUC) Family Influence on Acute Lymphoblastic Leukemia in Cancer and Non-Cancer Native American Populations from the Brazilian Amazon

The mucin (MUC) family includes several genes aberrantly expressed in multiple carcinomas and mediates diverse pathways essentials for oncogenesis, in both solid and hematological malignancies. Acute Lymphoblastic Leukemia (ALL) can have its course influenced by genetic variants, and it seems more frequent in the Amerindian population, which has been understudied. Therefore, the present work aimed to investigate the MUC family exome in Amerindian individuals from the Brazilian Amazon, in a sample containing healthy Native Americans (NAMs) and indigenous subjects with ALL, comparing the frequency of polymorphisms between these two groups. The population was composed of 64 Amerindians from the Brazilian Amazon, from 12 different isolated tribes, five of whom were diagnosed with ALL. We analyzed 16 genes from the MUC family and found a total of 1858 variants. We compared the frequency of each variant in the ALL vs. NAM group, which led to 77 variants with a significant difference and, among these, we excluded those with a low impact, resulting in 63 variants, which were distributed in nine genes, concentrated especially in MUC 19 (n = 30) and MUC 3A (n = 18). Finally, 11 new variants were found in the NAM population. This is the first work with a sample of native Americans with cancer, a population which is susceptible to ALL, but remains understudied. The MUC family seems to have an influence on the development of ALL in the Amerindian population and especially MUC19 and MUC3A are shown as possible hotspots. In addition, the 11 new variants found point to the need to have their clinical impact analyzed.

Triple-hit explanation for the worse prognosis of pediatric acute lymphoblastic leukemia among Mexican and Hispanic children

Acute lymphoblastic leukemia (ALL) is the most common malignancy among Mexican and Hispanic children and the first cause of death by disease in Mexico. We propose a "triple-hit" explanation for the survival gap affecting this population. The first hit can be attributed to epidemiology and social, cultural, and economic burdens. The second hit refers to cancer biology, with a high incidence of unfavorable genetic characteristics associated with an unfavorable response to treatment and, subsequently, poor survival. Finally, the third hit relates to sub-optimal treatment and support. Society and culture, leukemia biology, and treatment approach limitations are key factors that should not be seen apart and must be considered comprehensively in any strategy to improve the prognosis of Mexican and Hispanic children with ALL.

Molecular characteristics and outcomes in Hispanic and non-Hispanic patients with acute myeloid leukemia

Hispanic patients have been reported to have an increased incidence of AML and possibly inferior outcomes compared to non-Hispanics. We conducted a retrospective study of 225 AML patients (58 Hispanic and 167 non-Hispanic) at two academic medical centers in Florida. Disease characteristics, cytogenetics, mutation profiles, and clinical outcomes were assessed. Hispanic patients were younger at presentation than non-Hispanics (p = 0.0013). We found associations between single gene mutations and ethnicity, with IDH1 mutations being more common in non-Hispanics (95.2% vs. 4.8%, p = 0.0182) and WT1 mutations more common in Hispanics (62.5% vs. 37.5%, p = 0.0455). We also found an emerging trend towards adverse risk cytogenetics in Hispanic patients (p = 0.1796), as well as high risk fusions such as MLL-r (70% vs. 30%, p = 0.004). There was no difference in overall survival (OS) between Hispanic and non-Hispanics patients. When examining only newly diagnosed patients (n = 105), there was improved OS in Hispanics (median 44.7 months vs. 14 months, p = 0.026) by univariate analysis and equivalent OS by multivariate analysis (hazard ratio = 1.52 [95% CI = 0.74-3.15]). Hispanics with a driver mutation not class-defining had improved survival compared to non-Hispanics. Our study demonstrates significant genetic differences between Floridian Hispanics and non-Hispanics, but no difference in OS in patients treated at an academic medical center.

The impact of race, ethnicity, and obesity on CAR T-cell therapy outcomes

Cancer outcomes with chemotherapy are inferior in patients of minority racial/ethnic groups and those with obesity. Chimeric antigen receptor (CAR) T-cell therapy has transformed outcomes for relapsed/refractory hematologic malignancies, but whether its benefits extend commensurately to racial/ethnic minorities and patients with obesity is poorly understood. With a primary focus on patients with B-cell acute lymphoblastic leukemia (B-ALL), we retrospectively evaluated the impact of demographics and obesity on CAR T-cell therapy outcomes in adult and pediatric patients with hematologic malignancies treated with CAR T-cell therapy across 5 phase 1 clinical trials at the National Cancer Institute from 2012 to 2021. Among 139 B-ALL CAR T-cell infusions, 28.8% of patients were Hispanic, 3.6% were Black, and 29.5% were overweight/obese. No significant associations were found between race, ethnicity, or body mass index (BMI) and complete remission rates, neurotoxicity, or overall survival. Hispanic patients were more likely to experience severe cytokine release syndrome compared with White non-Hispanic patients even after adjusting for leukemia disease burden and age (odds ratio, 4.5; P = .001). A descriptive analysis of patients with multiple myeloma (n = 24) and non-Hodgkin lymphoma (n = 23) displayed a similar pattern to the B-ALL cohort. Our findings suggest CAR T-cell therapy may provide substantial benefit across a range of demographics characteristics, including for those populations who are at higher risk for chemotherapy resistance and relapse. However, toxicity profiles may vary. Therefore, efforts to improve access to CAR therapy for underrepresented populations and elucidate mechanisms of differential toxicity among demographic groups should be prioritized.

Disparities in trial enrollment and outcomes of Hispanic adolescent and young adult acute lymphoblastic leukemia

Contrary to population data, survival of Hispanic AYA ALL patients enrolled on CALGB 10403 was equivalent to non-Hispanic patients.

Geographical alignment between Hispanic patient incidence and trial sites may increase Hispanic patient enrollment onto clinical trials.

In this secondary analysis of Hispanic adolescents and young adults (AYA) with acute lymphoblastic leukemia (ALL) treated on Cancer and Leukemia Group B (CALGB) 10403, we evaluated outcomes and geographic enrollment patterns relative to US population data. We used demographic, clinical, and survival data on AYAs enrolled on CALGB 10403 (N = 295, 2007-2012). Surveillance, Epidemiology, and End Results registries provided overall survival (OS) for US AYA ALL by ethnicity/race. North American Association of Cancer Registries provided AYA ALL incidence overall and proportion among Hispanics by US state. Of AYAs enrolled on CALGB 10403, 263 (89%) reported ethnicity/race: 45 (17%) Hispanic, 172 (65%) non-Hispanic White (NHW), 25 (10%) non-Hispanic Black (NHB), and 21 (8%) other. Compared with NHWs, Hispanic and NHB patients had lower household income, and Hispanic patients were more likely to harbor high-risk CRLF2 aberrations. Relative to US estimates, where Hispanic patients represented 46% of newly diagnosed AYA ALL patients and experienced inferior OS compared with NHW (P < .001), Hispanic AYAs on CALGB 10403 did as well as NHW patients (3 year OS, 75% vs 74%; P = NS). Hispanic patients also had higher rates of protocol completion (P = .05). Enrollments on CALGB 10403 differed relative to the distribution of Hispanic AYA ALL in the United States: enrollment was highest in the Midwest; t and only 15% of enrollees were from states with a high proportion of Hispanic AYA ALL patients. In summary, Hispanic patients treated on CALGB 10403 did as well as NHWs and better than population estimates. Geographical misalignment between trial sites and disease epidemiology may partially explain the lower-than-expected enrollment of Hispanic AYA ALL patients.

Reporting of Racial and Ethnic Minority Representation in Early Phase Pediatric Oncology Clinical Trials

This letter to the editor considers outcomes for underrepresented populations across early phase pediatric oncology clinical trials, considering barriers to equitable representation of minorities in clinical trials.

Identification of Genomic Variants Associated with the Risk of Acute Lymphoblastic Leukemia in Native Americans from Brazilian Amazonia

A number of genomic variants related to native American ancestry may be associated with an increased risk of developing Acute Lymphoblastic Leukemia (ALL), which means that Latin American and hispanic populations from the New World may be relatively susceptible to this disease. However, there has not yet been any comprehensive investigation of the variants associated with susceptibility to ALL in traditional Amerindian populations from Brazilian Amazonia. We investigated the exomes of the 18 principal genes associated with susceptibility to ALL in samples of 64 Amerindians from this region, including cancer-free individuals and patients with ALL. We compared the findings with the data on populations representing five continents available in the 1000 Genomes database. The variation in the allele frequencies found between the different groups was evaluated using Fisher’s exact test. The analyses of the exomes of the Brazilian Amerindians identified 125 variants, seven of which were new. The comparison of the allele frequencies between the two Amerindian groups analyzed in the present study (ALL patients vs. cancer-free individuals) identified six variants (rs11515, rs2765997, rs1053454, rs8068981, rs3764342, and rs2304465) that may be associated with susceptibility to ALL. These findings contribute to the identification of genetic variants that represent a potential risk for ALL in Amazonian Amerindian populations and might favor precision oncology measures.

Residence in a Hispanic Enclave Is Associated with Inferior Overall Survival among Children with Acute Lymphoblastic Leukemia

Hispanic children with acute lymphoblastic leukemia (ALL) experience poorer overall survival (OS) than non-Hispanic White children; however, few studies have investigated the social determinants of this disparity. In Texas, many Hispanic individuals reside in ethnic enclaves-areas with high concentrations of immigrants, ethnic-specific businesses, and language isolation, which are often socioeconomically deprived. We determined whether enclave residence was associated with ALL survival, overall and among Hispanic children. We computed Hispanic enclave index scores for Texas census tracts, and classified children (N = 4083) as residing in enclaves if their residential tracts scored in the highest statewide quintile. We used Cox regression to evaluate the association between enclave residence and OS. Five-year OS was 78.6% for children in enclaves, and 77.8% for Hispanic children in enclaves, both significantly lower (p < 0.05) than the 85.8% observed among children not in enclaves. Children in enclaves had increased risk of death (hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.01-1.49) after adjustment for sex, age at diagnosis, year of diagnosis, metropolitan residence and neighborhood socioeconomic deprivation and after further adjustment for child race/ethnicity (HR 1.19, 95% CI 0.97-1.45). We observed increased risk of death when analyses were restricted to Hispanic children specifically (HR 1.30, 95% CI 1.03-1.65). Observations suggest that children with ALL residing in Hispanic enclaves experience inferior OS.

Clinical Outcomes of Patients With Newly Diagnosed Acute Lymphoblastic Leukemia in a County Hospital System

BACKGROUND

Major advances in the treatment of acute lymphoblastic leukemia (ALL) over the past decade have resulted in 5-year overall survival (OS) rates of 80% in mature B cell ALL, 50% in precursor B cell ALL, 50% to 60% in T cell ALL, and 60% to 70% in Philadelphia chromosome-positive (Ph+) ALL, as reported in studies from large, specialized centers. However, many patients treated in the community have limited access to novel therapies and stem cell transplantation (HSCT).

PATIENTS AND METHODS

The purpose of this retrospective cohort analysis was to evaluate the clinical outcomes of patients ≥ 16 years with newly diagnosed ALL treated from October 2007 to June 2019 in the Harris County Health System, Houston, TX.

RESULTS

One hundred forty-six patients were included, with newly diagnosed pre-B-ALL (n = 127), T-ALL (n = 18), and chronic myeloid leukemia and/or lymphoid blast crisis (n = 1). Median age was 35 years (16-82) at diagnosis, and 81(55%) were male. The majority of patients with pre-B ALL identified as Hispanic (n = 118, or 92%). Ninety-eight (67%) of patients were uninsured or indigent, receiving care under the county's financial assistance programs. Hyper-CVAD-based induction chemotherapy was administered in 134 (92%) of patients, while 9 (6%) were treated on different protocols, and 3 (2%) were not treated due to early death, or patient refusal. Imatinib was the most common TKI used in 17 of 30 or 57% of patients with Ph+ disease. Out of 137 evaluable for response patients, 117 (85%) achieved complete remission (CR + CRi), 19 (14%) had refractory disease, and 1 (1%) died within 4 weeks of diagnosis. Median follow-up time was 50 months (1.5-135). For the entire study cohort, the median duration of CR/CRi was 15.4 months. Out of 62 patients who were eligible for consolidative HSCT at first CR, 52 (89%) did not receive it, with lack of insurance being the most common reason (n = 29, or 56%). Barriers to utilization of novel therapies such as blinatumomab or CAR-T were also observed. Patient-caused delays in administration of chemotherapy and treatment interruptions of at least 30 days were seen in 31(23%) patients. At 1, 2, and 5 years, relapse rates were 37%, 56%, and 70%. Recurrent and/or refractory disease was the cause of death in most patients (n = 69 [85%]). Five-year EFS and OS rates were 22% and 38% for patients with pre-B ALL, 24% and 44% for patients with T ALL, and 13% and 27% for patients with Ph+ ALL. Median OS was significantly increased (not reached [NR] vs. 24 months; P = .00088) in patients with an indication for HSCT in first CR due to high-risk features who underwent HSCT, versus those who did not.

CONCLUSION

Addressing barriers raised by socioeconomic disparities, increasing access to effective therapies, and including patients with ALL treated in the community in clinical trials may improve survival for underserved populations.

Blood cancer health disparities in the United States Hispanic population

Cancer is a challenging, multifaceted disease that involves a combination of biological and nonbiological factors. Aside from COVID-19, cancer is the second leading cause of death in the United States and the first among Hispanic Americans. The Hispanic population is the largest minority group in the United States, which is rapidly growing in size. Unfortunately, U.S. Hispanics and other minority groups experience many different health disparities, resulting in poor survival outcomes and a reduced quality of life. Factors such as genomic mutations, lower socioeconomic status, lack of education, reduced access to health care, comorbidities, and environmental factors all contribute to these health-care inequalities. In the context of blood cancer health disparities, Hispanic patients are often diagnosed at a younger age and have worse outcomes compared with non-Hispanic individuals. In this commentary, we highlight the existing knowledge about cancer health disparities in the Hispanic population, with a focus on chronic and acute leukemia. In our experience at the U.S./Mexican border, analysis of several different blood cancers demonstrated that younger Hispanic patients with acute lymphoid or myeloid leukemia have higher incidence rates and worse prognoses. A combined approach, involving improved health-care access and better knowledge of the underlying factors, will allow for more timely diagnoses and the development of intervention strategies aimed at reducing or eliminating the disparities.

Understanding and Addressing Disparities in Patients With Hematologic Malignancies: Approaches for Clinicians

Approximately 185,840 individuals will be diagnosed with hematologic malignancies in the United States in 2020. Disparities in disease incidence, prevalence, burden, mortality, and survivorship have been identified among this patient population. Contributing factors include genetic ancestry, race/ethnicity, sex, socioeconomic status, and geographic region. Historically, these inequities have been understudied. Addressing these disparities requires a systems-level approach, improving access to care and reducing biases in the clinical setting. Additional research is needed to construct comprehensive, multilevel models to explore systematic observational studies and perform strategic intervention trials to overcome these disparities.

Association between the TPMT*3C (rs1142345) Polymorphism and the Risk of Death in the Treatment of Acute Lymphoblastic Leukemia in Children from the Brazilian Amazon Region

Acute lymphoblastic leukemia (ALL) is the leading cause of death from pediatric cancer worldwide. However, marked ethnic disparities are found in the treatment of childhood ALL with less effective results and higher mortality rates being obtained in populations with a high level of Native American ancestry. Genetic variations of the patient can affect resistance to ALL chemotherapy and potentially play an important role in this disparity. In the present study, we investigated the association of 16 genetic polymorphisms with the cell and metabolic pathways of the chemotherapeutic agents used in the treatment of ALL with the risk of death in treating childhood ALL in patients with a high contribution of Amerindian ancestry, coming from the Brazilian Amazon. The study included 121 patients with B-cell ALL treated with the BFM-2002 protocol. We are the first to identify the association between the TPMT gene rs1142345 polymorphism and the high risk of death in treating childhood ALL. Patients with the CC genotype had an approximately 25.5 times higher risk of dying during treatment of the disease than patients with other genotypes (p = 0.019). These results may help elucidate how the patient's genetic characteristics contribute to the mortality disparity in populations with a high contribution of Native American ancestry. The rs1142345 variant of the TPMT gene could be used as a potential marker to early stratify patients at high risk of death in treating childhood ALL in the investigated population.