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Previous studies from our research group have shown that trisomy 8 and the amplification of the 8q24.21 region is very frequent in gastric cancer (GC). Little is known about the role of most genes located in this region. Thus, the aim of this study was to understand the possible impact of transcriptional alterations and copy number variation (CNV) of four genes located in the 8q24.21 region - FAM49B, FAM84B, GSDMC and miR-5194 - in GC.Fifty-one to 85 matched pairs of tumoral and adjacent non-tumoral gastric tissues, from patients with primary GC, were used to analyze gene expression and CNV of the selected genes. We also included 29 H. pylori negative and gastritis negative gastric mucosa tissues from individuals without cancer obtained by endoscopy, as control samples.The expression of FAM49B, GSDMC and miR-5194 was higher in both tumoral and adjacent non-tumoral samples compared to the negative control. The expression of FAM84B showed no significant difference between tumoral samples and negative controls. However, the expression of FAM84B in the adjacent non-tumoral samples was higher compared to negative control and tumoral samples. Moreover, the higher expression of GSDMC was associated with T3 and T4 tumors, with tumors on stage III and IV and with advanced tumors. Higher copy numbers of FAM49B and GSDMC were associated with intestinal tumor type and with moderately or well-differentiated tumors. Higher copy number of FAM84B was associated with moderately or well-differentiated tumors. Furthermore, the expression of all four genes was positively correlated.All four genes are upregulated in GC and may play an important role in these neoplasms. GSDMC expression was associated with more aggressive tumors.

The five-year survival rate for metastatic pancreatic cancer is currently only 3%, which increases to 13% with local invasion only and to 39% with localized disease at diagnosis. Here we evaluated repurposed mebendazole, an approved anthelminthic drug, to determine how mebendazole might work at the different stages of pancreatic cancer formation and progression. We asked if mebendazole could prevent initiation of pancreatic intraepithelial neoplasia precursor lesions, interfere with stromal desmoplasia, or suppress tumor growth and liver metastasis. In both the KrasLSL.G12D/+; Pdx1-Cre (KC) mouse model of caerulein-induced inflammatory pancreatitis and the KrasLSL.G12D/+; Tp53R172H/+; Pdx1-Cre (KPC) mouse model of advanced pancreatic cancer, mebendazole significantly reduced pancreas weight, dysplasia and intraepithelial neoplasia formation, compared to controls. Mebendazole significantly reduced trichrome-positive fibrotic connective tissue and α-SMA-positive activated pancreatic stellate cells that heralds fibrogenesis. In the aggressive KPC model, mebendazole significantly suppressed pancreatic tumor growth, both as an early and late intervention. Mebendazole reduced the overall incidence of pancreatic cancer and severity of liver metastasis in KPC mice. Using early models of pancreatic cancer, treatment with mebendazole resulted in less inflammation, decreased dysplasia, with the later stage model additionally showing a decreased tumor burden, less advanced tumors, and a reduction of metastasis. We conclude that mebendazole should be investigated further as a component of adjuvant therapy to slow progression and prevent metastasis, and well as for primary prevention in the highest risk patients.

Identifying a microbiome pattern in gastric cancer (GC) is hugely debatable due to the variation resulting from the diversity of the studied populations, clinical scenarios, and metagenomic approach. H. pylori remains the main microorganism impacting gastric carcinogenesis and seems necessary for the initial steps of the process. Nevertheless, an additional non-H. pylori microbiome pattern is also described, mainly at the final steps of the carcinogenesis. Unfortunately, most of the presented results are not reproducible, and there are no consensual candidates to share the H. pylori protagonists. Limitations to reach a consistent interpretation of metagenomic data include contamination along every step of the process, which might cause relevant misinterpretations. In addition, the functional consequences of an altered microbiome might be addressed. Aiming to minimize methodological bias and limitations due to small sample size and the lack of standardization of bioinformatics assessment and interpretation, we carried out a comprehensive analysis of the publicly available metagenomic data from various conditions relevant to gastric carcinogenesis. Mainly, instead of just analyzing the results of each available publication, a new approach was launched, allowing the comprehensive analysis of the total sample amount, aiming to produce a reliable interpretation due to using a significant number of samples, from different origins, in a standard protocol. Among the main results, Helicobacter and Prevotella figured in the “top 6” genera of every group. Helicobacter was the first one in chronic gastritis (CG), gastric cancer (GC), and adjacent (ADJ) groups, while Prevotella was the leader among healthy control (HC) samples. Groups of bacteria are differently abundant in each clinical situation, and bacterial metabolic pathways also diverge along the carcinogenesis cascade. This information may support future microbiome interventions aiming to face the carcinogenesis process and/or reduce GC risk.

Gastric cancer is the fifth most common cancer worldwide. Investigations of lifestyle factors such as physical activity may identify risk patterns in this population. Thus, the aim of this study was to analyze the level of habitual physical activity and its association with the risk of gastric adenocarcinoma in the Amazon region. We conducted a hospital-based case-control study. Questionnaires investigating sociodemographic characteristics and physical activity were applied between July 2017 and April 2019. To assess habitual physical activity, we used the Baecke Physical Activity Questionnaire, which assessed physical exercise (PE), occupational physical activity, and leisure and locomotion activity (LLA). The Chi-square association test was applied and univariate and multiple binary logistic regression models were used for odds ratio analysis. The descriptive level of 5% (P < 0.05) was selected for statistical significance. The sample consisted of 297 individuals, with 147 cases and 150 controls. Those who performed PE at the second percentile level for 5 years before the interview were 71% less likely to develop gastric cancer (P = 0.012). Individuals with the highest LLA levels during the preceding 10 and 15 years were 76 and 78% less likely to have gastric cancer, respectively. In this study, physical activity related to sport and to leisure and locomotion was an independent protective factor that was inversely associated with gastric cancer.

MYC overexpression is a common phenomenon in gastric carcinogenesis. In this study, we identified genes differentially expressed with a downregulated profile in gastric cancer (GC) cell lines with silenced MYC. The TTLL12, CDKN3, CDC16, PTPRA, MZT2B, UBE2T genes were validated using qRT-PCR, western blot and immunohistochemistry in tissues of 213 patients with diffuse and intestinal GC. We identified high levels of TTLL12, MZT2B, CDC16, UBE2T, associated with early and advanced stages, lymph nodes, distant metastases and risk factors such as H. pylori. Our results show that in the diffuse GC the overexpression of CDC16 and UBE2T indicate markers of poor prognosis higher than TTLL12. That is, patients with overexpression of these two genes live less than patients with overexpression of TTLL12. In the intestinal GC, patients who overexpressed CDC16 had a significantly lower survival rate than patients who overexpressed MZT2B and UBE2T, indicating in our data a worse prognostic value of CDC16 compared to the other two genes. PTPRA and CDKN3 proved to be important for assessing tumor progression in the early and advanced stages. In summary, in this study, we identified diagnostic and prognostic biomarkers of GC under the control of MYC, related to the cell cycle and the neoplastic process.

Background Apoptosis is a type of cell death involved in different pathways inherent to the cell and the evasion from this mechanism has been related to cancer, although this process remains not very well comprehended. Gastric cancer (GC) is one of the most incident and aggressive types of cancer worldwide. In this study, we analyzed the distribution of INDEL variants in GC patients (Case) and individuals from the general population (Control) from the Amazon region, in which GC is remarkably frequent. Methods A panel of nine INDEL markers in apoptosis-related genes (BCL2 rs11269260, CASP3 rs4647655, CASP8 rs3834129 and rs59308963, CASP9 rs4645982 and rs61079693, FADD rs4197, FAS rs10562972 and TP53 rs17880560) was developed and genotyped by multiplex PCR in both groups. Results In our analyses, only marker rs4197 (FADD gene) was associated to GC development as follows: INS/DEL genotype of rs4197 increasing in about 2-fold the chances of developing this type of cancer (P = 0.046; OR = 1.940; 95%CI = 1.011–3.725). Conclusion Our results suggest that rs4197 (FADD gene) might play a role in gastric carcinogenesis in the investigated population. More studies are needed to clarify this relation. Here, we highlight the importance of investigating INDEL variants in genes involved in apoptosis.

Background adoptive immunotherapy is a promising cancer therapy. Immune cells are capable of recognizing and destroying cancer cells and represent a powerful strategy, however, this approach remains technically complicated, due to the need to select and isolate immune cells from these, present cancer antigens to those cells, expanding and reinjecting them. Lymph nodes recovered during gastric cancer surgery may represent an option for immunotherapy, since they harbor an enormous amount of immune cells, which have already been presented to cancer antigens. The advantage of selecting only cancer-negative lymph has not been determined yet. The status of immune checkpoints in the immune cells within the lymph nodes was analyzed in order to try to solve this problem. Materials and methods Tissue microarrays were constructed and automated immunostaining for PD-1 and PD-L1 was performed on 143 lymph nodes from 70 patients with gastric adenocarcinoma. Results In positive nodes, PD-L1 was only positivity in cancer cells (6%) and PD-1 was positive for B lymphocytes (60%), T lymphocytes (70%) and one case in cancer cells (2.5%). In negative nodes, most cases were positive for PD-1 in B (73.1%) and T (71.65%) lymphocytes. Conclusions Expression of PD-1 and PD-L1 in gastric cancer lymph nodes was demonstrated for the first time. PD-1 is expressed in positive and negative nodes, which could activate the PD-1 pathway. Lymphocytes from tumor-free lymph nodes were negative for PD-L1, and this might represent an advantage for selecting these lymph nodes as a potential source of immune cells for adoptive immunotherapy.

Highlights • This is a borderline tumor with indolent biological behavior. • There are still multiple poorly understood factors that can dictate its malignant transformation and prognosis. • Here, a rare tumor whose age and survival are tangent the literature reports describe. • There is a need for a long and rigorous segment to identify possible long-term metastases., Introduction Frantz’s Tumor or Solid Pseudopapillary Neoplasm (SPN) is rare with a solid-cystic pattern, and most common in young women. Presentation of case This study based on guidelines for case reports (SCARE) reports a case of SPN in a teenager aged 13 years at the diagnosis time, attended at a teaching public hospital in Brazil, which evolved into liver metastases. Clinical, laboratory, therapeutic and imaging data were collected from the physical chart and analyzed in light of current publications on the topic. The first consultation occurred in January 2012, where weight loss, fever, vomiting, left-sided hypochondrium and epigastric pain were reported. Imaging exams evidenced an expansive heterogeneous process in the pancreatic tail; however, laboratory exams and tumor markers did not present alteration in relation to reference values. In March of 2012, she underwent caudal body pancreatectomy, splenectomy, segmental colectomy and colo-coloanastomosis as a function of the intraoperative findings. After 63 months, right-sided hepatectomy was performed to resect metastases. Currently, she is undergoing outpatient monitoring, without complaint or alterations in imaging and laboratory exams, totaling 100 months of global survival. Discussion This is an interesting case report of a rare tumor, in so far as without any adjuvant chemotherapies, an 8-year long survival time could be achieved in this particular type of tumor despite initially large tumor expansion and later liver metastases. Conclusion Additional epidemiological studies, molecular and clinical trials are required to increase knowledge on SPN.

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Very few therapeutic options are currently available in this neoplasia. The use of 5-Aza-2'-deoxycytidine (5-AZAdC) was approved for the treatment of myelodysplastic syndromes, and this drug can treat solid tumours at low doses. Epigenetic manipulation of GC cell lines is a useful tool to better understand gene expression regulatory mechanisms for clinical applications. Therefore, we compared the gene expression profile of 5-AZAdC-treated and untreated GC cell lines by a microarray assay. Among the genes identified in this analysis, we selected NRN1 and TNFAIP3 to be evaluated for gene expression by RT-qPCR and DNA methylation by bisulfite DNA next-generation sequencing in 43 and 52 pairs of GC and adjacent non-neoplastic tissue samples, respectively. We identified 83 candidate genes modulated by DNA methylation in GC cell lines. Increased expression of NRN1 and TNFAIP3 was associated with advanced tumours (P 0.05). We showed that increased NRN1 and TNFAIP3 expression seems to be regulated by DNA demethylation in GC samples: inverse correlations between the mRNA and DNA methylation levels in the promoter of NRN1 (P 0.05) and the intron of TNFAIP3 (P 0.05) were detected. Reduced NRN1 promoter methylation was associated with III/IV TNM stage tumours (P = 0.03) and the presence of Helicobacter pylori infection (P = 0.02). The identification of demethylated activated genes in GC may be useful in clinical practice, stratifying patients who are less likely to benefit from 5-AZAdC-based therapies. KEY MESSAGES: Higher expression of NRN1 and TNFAIP3 is associated with advanced gastric cancer (GC). NRN1 promoter hypomethylation contributes to gene upregulation in advanced GC. TNFAIP3 intronic-specific CpG site demethylation contributes to gene upregulation in GC. These findings may be useful to stratify GC patients who are less likely to benefit from DNA demethylating-based therapies.

Gastric cancer remains one of the most lethal cancers. The incidence and mortality rates are quite similar. The main reason for the high mortality is diagnosis at advanced stages of disease, when treatment options are poor. One of the supposed strategies to overcome late-stage diagnosis is identifying people at high risk with the aim of establishing rigorous clinical control, including routine endoscopy and biopsies. Hereditary gastric cancer (HGC) syndromes, though representing a sizeable group to monitor for prevention or, at least, for early diagnosis, are apparently extremely rare. The low rate of HGC diagnosis might be related to the low rates of suspicion, insufficient familiarity about clinical diagnosis criteria, and the supposed conditional necessity of a molecular diagnosis. In this review, we will discuss simple measures to increase HGC diagnosis by applying three rules that might provide an opportunity for precision care to benefit the families affected by this disease.

Circulating tumor DNA (ctDNA) has recently emerged as a minimally invasive “liquid biopsy” tool in precision medicine. ctDNA-genomic DNA fragments that are released into the bloodstream after the active secretion of microvesicles or tumor cell lysis reflects tumor evolution and the genomic alterations present in primary and/or metastatic tumors. Notably, ctDNA analysis might allow the stratification of patients, the monitoring of the therapeutic response, and the establishment of an opportunity for early intervention independent of detection by imaging modalities or clinical symptoms. As oncology moves towards precision medicine, the information in ctDNA provides a means for the individual management of the patient based on their tumor's genetic profile. This review presents current evidence on the potential role for ctDNA in helping to guide individualized clinical treatment decisions for patients with melanoma, castration-resistant prostate cancer, breast cancer, metastatic colorectal cancer, and non–small cell lung cancer.

Background: Despite decreasing global incidence trends, gastric cancer is still among the five most incident cancers in the world and the third cancer-related cause of death. In Brazil, differences in incidence and mortality exist depending on the geographic region studied. Objective: To describe the incidence, mortality, trends and age-period-cohort of gastric cancer in three cities of Brazil (Sao Paulo, Belem and Fortaleza), in the period 1990-2012. Mortality for gastric cancer in Brazil overall and by region was described. Methods: 33,462 incident cases of gastric cancer were identified from the population-based cancer registries and 23,424 deaths from mortality information system in residents of the three cities and in Brazil were included in the study. Data for incident cases were extracted from the Population Based Cancer Registries from the National Cancer Institute (INCA). Mortality data on gastric cancer were extracted from Information Technology Department of Brazilian Public Health Care System/Health Ministry (DATASUS/MS). Mortality and incidence age standardized rates were calculated. For trends analysis the Joinpoint Regression and age-period-cohort model were applied. Results: Belem presented the highest incidence rates for gastric adenocarcinoma. Decreasing incidence trends were identified in Sao Paulo (-7.8% in men; -6.3% in women) and in Fortaleza (-1.2% in men). Increasing incidence trends were observed for women in Belem (1.8%) and Fortaleza (1.1%). In Belem (Amazon area), there was an increased risk for gastric cancer in women born after the 1960s. Overall in Brazil mortality for gastric cancer is decreasing. Mortality trends showed significant reduction, for both sexes, in the three Brazilian cities. Conclusion: Incidence of gastric cancer is increasing in women born in the sixties in Belem (Amazon region) and Fortaleza (Northeast region). In Brazil there was increase in mortality in Northeast region and decrease in others regions. More update data on incidence for Amazon and Northeast region is needed.

Despite being one of the most studied cancer-related infections, the relationship between Helicobacter pylori infection and gastric adenocarcinoma (GC) remains, in some points, obscure. Based on a critical analysis of the available literature regarding stomach microbiota, we aimed to shed light to a possible new interpretation of the current understanding about the Helicobacter pylori-related GC carcinogenesis. We analyzed data from the literature on Helicobacter pylori and other potential carcinogenic pathogens, in both benignant conditions and gastric adenocarcinoma. Helicobacter pylori is the dominant microorganism in benignant conditions as non-complicated gastritis. In atrophic gastritis, metaplasia and, mainly, in gastric adenocarcinoma, a strong reduction in Helicobacter pylori abundance, and increased occurrence of other microorganisms is strongly demonstrated by metagenomic experiments. While causing peptic disease and keeping the stomach's high acidity, Helicobacter pylori infection avoids gastric infection by carcinogenic intestinal microbiota. Nevertheless, Helicobacter pylori persistence may also provoke an atrophic gastritis, a condition that causes its own decline, due to a microenvironment modification, including reduced acidity, resulting in Helicobacter pylori substitution by a cancer-prone microbiota. This new interpretation might result in a dramatic modification on clinical management of Helicobacter pylori-related gastric disease.

Background Susceptibility to Chronic Myeloid Leukemia (CML) may be modulated by genetic variables. However, the majority of previous investigations have focused on genetically homogeneous populations, resulting in a lack of evidence on how genetic factors may influence the development of CML in miscegenated populations. We analyzed 30 polymorphisms in genes related to DNA repair, folate metabolism, transmembrane transport, xenobiotic metabolism, and pyrimidine synthesis in relation to their potential role in the susceptibility of the individual to CML. Methods This case‐control study included 126 healthy individuals and 143 patients diagnosed with CML from the admixed population of the Brazilian Amazon. The samples were genotyped by real‐time PCR and the genetic ancestry analysis was based on a panel of 61 ancestry informative markers. Results The results indicated a protective effect against the development of CML in carriers of the C allele of the rs28399433 (CYP2A6) gene and the CC genotype of the rs3742106 (ABCC4) gene. Conclusion Our findings suggest that the rs3742106 (ABCC4) and rs28399433 (CYP2A6) polymorphisms may modulate susceptibility to CML in a population of the Brazilian Amazon region., Susceptibility to chronic myeloid leukemia may be modulated by genetic variables. The accumulated evidence of genetic players in CML development may not be applied to highly admixed populations since their allelic frequencies vary widely between groups with distinct ancestry backgrounds. Thus, we analyzed 30 polymorphisms in genes involved in transport and metabolism pathways in patients with CML from the Brazilian Amazon, one of the most genetically heterogeneous population worldwide.

Coronavirus disease 2019 (COVID-19) rapidly transformed into a global pandemic, for which a demand for developing antivirals capable of targeting the SARS-CoV-2 RNA genome and blocking the activity of its genes has emerged. In this work, we presented a database of SARS-CoV-2 targets for small interference RNA (siRNA) based approaches, aiming to speed the design process by providing a broad set of possible targets and siRNA sequences. The siRNAs sequences are characterized and evaluated by more than 170 features, including thermodynamic information, base context, target genes and alignment information of sequences against the human genome, and diverse SARS-CoV-2 strains, to assess possible bindings to off-target sequences. This dataset is available as a set of four tables, available in a spreadsheet and CSV (Comma-Separated Values) formats, each one corresponding to sequences of 18, 19, 20, and 21 nucleotides length, aiming to meet the diversity of technology and expertise among laboratories around the world. A metadata table (Supplementary Table S1), which describes each feature, is also provided in the aforementioned formats. We hope that this database helps to speed up the development of new target antivirals for SARS-CoV-2, contributing to a possible strategy for a faster and effective response to the COVID-19 pandemic.

Background Next generation sequencing (NGS) has been a handy tool in clinical practice, mainly due to its efficiency and cost-effectiveness. It has been widely used in genetic diagnosis of several inherited diseases, and, in clinical oncology, it may enhance the discovery of new susceptibility genes and enable individualized care of cancer patients. In this context, we explored a pan-cancer panel in the investigation of germline variants in Brazilian patients presenting clinical criteria for hereditary cancer syndromes or familial history. Methods Seventy-one individuals diagnosed or with familial history of hereditary cancer syndromes were submitted to custom pan-cancer panel including 16 high and moderate penetrance genes previously associated with hereditary cancer syndromes (APC, BRCA1, BRCA2, CDH1, CDKN2A, CHEK2, MSH2, MSH6, MUTYH, PTEN, RB1, RET, TP53, VHL, XPA and XPC). All pathogenic variants were validated by Sanger sequencing. Results We identified a total of eight pathogenic variants among 12 of 71 individuals (16.9%). Among the mutation-positive subjects, 50% were diagnosed with breast cancer and had mutations in BRCA1, CDH1 and MUTYH. Notably, 33.3% were individuals diagnosed with polyposis or who had family cases and harbored pathogenic mutations in APC and MUTYH. The remaining individuals (16.7%) were gastric cancer patients with pathogenic variants in CDH1 and MSH2. Overall, 54 (76.05%) individuals presented at least one variant uncertain significance (VUS), totalizing 81 VUS. Of these, seven were predicted to have disease-causing potential. Conclusion Overall, analysis of all these genes in NGS-panel allowed the identification not only of pathogenic variants related to hereditary cancer syndromes but also of some VUS that need further clinical and molecular investigations. The results obtained in this study had a significant impact on patients and their relatives since it allowed genetic counselling and personalized management decisions.

Gastric cancer (GC) is a worldwide health problem, making it one of the most common types of cancer, in fifth place of all tumor types, and the third highest cause of cancer deaths in the world. There is a subgroup of GC that consists of tumors infected with the Epstein–Barr virus (EBV) and is characterized mainly by the overexpression of programmed cell death protein-ligand-1 (PD-L1). In the present study, we present histopathological and survival data of a thousand GC patients, associated with EBV status and PD-L1 expression. Of the thousand tumors analyzed, 190 were EBV-positive and the vast majority (86.8%) had a high relative expression of mRNA and PD-L1 protein (p &lt, 0.0001) in relation to non-neoplastic control. On the other hand, in EBV-negative samples, the majority had a low PD-L1 expression of RNA and protein (p &lt, 0.0001). In the Kaplan–Meier analysis, the probability of survival and increased overall survival of EBV-positive GC patients was impacted by the PD-L1 overexpression (p &lt, 0.0001 and p = 0.004, respectively). However, the PD-L1 low expression was correlated with low overall survival in those patients. Patients with GC positive for EBV, presenting PD-L1 overexpression can benefit from immunotherapy treatments and performing the quantification of PD-L1 in gastric neoplasms should be adopted as routine.

Estimates show that 5&ndash, 10% of breast cancer cases are hereditary, caused by genetic variants in autosomal dominant genes, of these, 16% are due to germline mutations in the BRCA1 and BRCA2 genes. The comprehension of the mutation profile of these genes in the Brazilian population, particularly in Amazonian Amerindian groups, is scarce. We investigated fifteen polymorphisms in the BRCA1 and BRCA2 genes in Amazonian Amerindians and compared the results with the findings of global populations publicly available in the 1000 Genomes Project database. Our study shows that three variants (rs11571769, rs144848, and rs11571707) of the BRCA2 gene, commonly associated with hereditary breast cancer, had a significantly higher allele frequency in the Amazonian Amerindian individuals in comparison with the African, American, European, and Asian groups analyzed. These data outline the singular genetic profiles of the indigenous population from the Brazilian Amazon region. The knowledge about BRCA1 and BRCA2 variants is critical to establish public policies for hereditary breast cancer screening in Amerindian groups and populations admixed with them, such as the Brazilian population.

Marianne Rodrigues Fernandes,1,2 Juliana Carla Gomes Rodrigues,1 Olalla Maroñas,3 Ana Latorre-Pellicer,3,4 Raquel Cruz,5 João Farias Guerreiro,6 Rommel Mario Rodriguez Burbano,1,2 Paulo Pimentel de Assumpção,1 Andrea Ribeiro-dos-Santos,1,6 Sidney Emanuel Batista dos Santos,1,6 Angel Carracedo,3,5,7 Ney Pereira Carneiro dos Santos1 1Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém, Pará, Brazil; 2Departamento de ensino e pesquisa, Hospital Ophir Loyola, Belém, Pará, Brazil; 3Grupo de Medicina Xenómica, Centro Nacional de Genotipado (CEGEN-PRB3), Universidade de Santiago de Compostela, Santiago de Compostela, España; 4Unidad de Genética Clínica y Genómica Funcional, Departamento de Farmacología-Fisiología, Escuela de Medicina, Universidad de Zaragoza, IIS-Aragón, E-50009 Zaragoza, España; 5Centro de Investigación Biomédica en Enfermedades Raras (CIBERER), Grupo de Medicina Genómica, CIMUS, Universidad de Santiago de Compostela, Santiago de Compostela, España; 6Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém, Pará, Brazil; 7Fundación Pública de Medicina Xenómica, Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, EspañaCorrespondence: Ney Pereira Carneiro dos SantosHospital Universitário João de Barros Barreto, Núcleo de Pesquisa em Oncologia, 2º Floor of the Unidade de Alta Complexidade em Oncologia. Av. Mundurucus, 4487, Guamá, Belém 66073-005, PA, BrazilTel +55 (91) 99113-9221Email npcsantos.ufpa@gmail.comIntroduction: The genetic admixture of the Brazilian population has considerable relevance to the implementation of the principles of pharmacogenomics (PGx), as it may compromise the extrapolation of data obtained in more homogeneous world populations.Purpose: This study aims to investigate a panel of 117 polymorphisms in 35 pharmacogenes, which contains label recommendations or clinical evidence by international drug regulatory agencies, in Amazonian Native American populations, and compare the results obtained with continental population data from the 1000 Genomes Project Consortium.Patients and Methods: The study population is composed of 109 Native American individuals from three Brazilian Amazon groups. The genotyping of the PGx polymorphisms was performed by allelic discrimination using TaqMan® OpenArray Genotyping with a panel of 120 customized assays on the QuantStudio™ 12K Flex Real-Time PCR System.Results: Statistical differences within the Native American populations were observed regarding both genotypes and phenotypes of some genes of the CYP family. The discriminant analysis of principal components (DAPCs) between the NAM group and the continental populations of the 1000 Genomes Project resulted in the clustering of the three Native American populations. Additionally, in general, the NAM group was determined to be closely situated between East Asia, America, and South Asia groups, which enabled us to infer a genetic similarity between these populations. The DAPC analysis further demonstrated that eight polymorphisms and six polymorphisms were more relevant in differentiating the NAM from the continental populations and the NAM populations among themselves, respectively.Conclusion: Some investigated polymorphisms show differences among world populations, particularly with populations of European origin, for whom precision medicine protocols are primarily designed. The accumulated knowledge regarding these variations may assist in the design of specific protocols for Native American populations and populations admixed with them.Keywords: Native Americans, pharmacogenomics, polymorphisms, population, genetic admixture, Brazil

The loss of teeth and lack of oral hygiene have been associated with the risk of developing gastric cancer (GC) in several populations evidenced in epidemiological studies. In this study, we quantitatively compared the proportion of oral pathogens in individuals with gastric cancer and individuals without cancer in a referral hospital in the city of Belem, Brazil. This study evaluated 192 patients with GC and 192 patients without cancer. Periodontal clinical examination was performed, and all individuals were submitted to the collection of salivary and dental biofilms. When comparing the median periodontal indexes in the gastric and cancer-free groups, it was statistically significant (p < 0.001) in the gastric cancer group compared to the probing depth of the periodontal pocket. Levels of bacterial DNA were observed in saliva and dental plaque, with a statistically significant difference (p < 0.001) between individuals with cancer and without neoplasia in all the bacteria surveyed. Significant relationships (p < 0.001) between biological agents and GC have been found in bacterial species that cause high rates of periodontal pathology and caries. The results suggest a different quantitative association in the presence of oral pathogens between individuals without cancer and patients with GC. As noted, it cannot be said that the bacteria present in the oral cavity increase the risk of gastric cancer or are aggravating factors of the disease. However, it is worth mentioning that, as it is part of the digestive system, the lack of care for the oral cavity can negatively affect the treatment of patients with gastric cancer.

Gastric cancer (GC) represents a notable amount of morbidity and mortality worldwide. Understanding the molecular basis of CG will offer insight into its pathogenesis in an attempt to identify new molecular biomarkers to early diagnose this disease. Therefore, studies involving small non-coding RNAs have been widely explored. Among these, PIWI-interacting RNAs (piRNAs) are an emergent class that can play important roles in carcinogenesis. In this study, small-RNA sequencing was used to identify the global piRNAs expression profile (piRNome) of gastric cancer patients. We found 698 piRNAs in gastric tissues, 14 of which were differentially expressed (DE) between gastric cancer (GC), adjacent to gastric cancer (ADJ), and non-cancer tissues (NC). Moreover, three of these DE piRNAs (piR-48966*, piR-49145, piR-31335*) were differently expressed in both GC and ADJ samples in comparison to NC samples, indicating that the tumor-adjacent tissue was molecularly altered and should not be considered as a normal control. These three piRNAs are potential risk biomarkers for GC, especially piR-48966* and piR-31335*. Furthermore, an in-silico search for mRNAs targeted by the differentially expressed piRNAs revealed that these piRNAs may regulate genes that participate in cancer-related pathways, suggesting that these small non-coding RNAs may be directly and indirectly involved in gastric carcinogenesis.

Arapaima gigas is a giant bony tongue air-breathing fish, and a promising species for aquaculture due to its particular features. However, there is still a lack of information on its biology and few transcriptome studies are available. Our aim was to characterize the transcriptome of arapaima in order to shed light on molecular networks contributing to its unique traits. Through RNA-sequencing, we generated a transcriptome from eight tissues (brain, pituitary, heart, muscle, kidney, lung, ovary, and testis) collected from arapaima adults specimens. Using a genome-guided strategy associated with homologous protein evidence, 57,706 transcripts were assembled, which aligned to 23,353 high confidence protein-coding genes. The analysis revealed a global view of expression patterns, as well as it allowed us to identify tissue-specific gene clusters, transcription factors within the clusters, and to compare expression patterns between male and female. These analyses has generated tissue-specific and sex-biased transcriptome profiles, which will be helpful to understand its molecular biology, evolution, and also guide future functional studies of the arapaima.

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&rsquo, 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.

Background: Since the publication of the first Brazilian Consensus on Gastric Cancer (GC) in 2012 carried out by the Brazilian Gastric Cancer Association, new concepts on diagnosis, staging, treatment and follow-up have been incorporated. Aim: This new consensus is to promote an update to professionals working in the fight against GC and to provide guidelines for the management of patients with this condition. Methods: Fifty-nine experts answered 67 statements regarding the diagnosis, staging, treatment and prognosis of GC with five possible alternatives: 1) fully agree; 2) partially agree; 3) undecided; 4) disagree and 5) strongly disagree A consensus was adopted when at least 80% of the sum of the answers “fully agree” and “partially agree” was reached. This article presents only the responses of the participating experts. Comments on each statement, as well as a literature review, will be presented in future publications. Results: Of the 67 statements, there was consensus in 50 (74%). In 10 declarations, there was 100% agreement. Conclusion: The gastric cancer treatment has evolved considerably in recent years. This consensus gathers consolidated principles in the last decades, new knowledge acquired recently, as well as promising perspectives on the management of this disease.

Colorectal (CRC) and gastric (GC) cancers are associated with increased morbidity and mortality. Single nucleotide polymorphisms (SNPs) of xenobiotic metabolism and transporter genes may play a role in the individual responses to exposure to substances implicated in susceptibility to cancer. The investigation of the genetic variation related to the activation and detoxification of xenobiotics may thus help to clarify the prevalence of neoplasms. We analyzed the role of 30 SNPs in xenobiotic-metabolizing and transporter genes in susceptibility to CRC and GC. The study included individuals diagnosed with CRC (n = 121) and GC (n = 95), and 141 controls (non-cancer patients) from the population of Belém, in the Brazilian Amazon. The results indicated an association between the polymorphisms rs2231142 (P = 0.013; OR = 3.01; 95% CI = 1.26-7.13), in the ABCG2 gene, and rs1801159 (P = 0.03; OR = 2.35; 95% CI = 1.14-5.05), in DPYD gene, with the risk of developing GC. The polymorphism rs17116806 of the DPYD gene was found to be associated with a lower risk of developing gastric (P≤0.0001; OR = 0.043; 95% CI = 0.015-0.12) or colorectal (P≤0.0001; OR = 0.076; 95% CI = 0.33-0.18) cancers, indicating that the same variant may play a similar role in different types of cancer tissue. Additionally, the carriers of the TT genotype of the polymorphism in the ABCB1 gene (rs1128503) presented a reduced probability of developing CRC (P = 0.0001; OR = 0.16; 95% CI = 0.06-0.41) as well as GC (P = 0.007; OR = 0.27; 95% CI = 0.1-0.7). Our findings indicate that polymorphisms in xenobiotic-metabolizing and transporter genes may modulate susceptibility to colorectal and gastric cancers.

In recent years, the incidence of tuberculosis (TB) has declined worldwide, although this disease still occurs at relatively high rates in Amerindian populations. This suggests that the genetic ancestry of Amerindians may be an important factor in the development of infections, and may account for at least some of the variation in infection rates in the different populations. The present study investigated the potential influence of Amerindian genetic ancestry on susceptibility to tuberculosis in an Amazon population. The study included 280 patients diagnosed with tuberculosis and 138 asymptomatic hospital employees with no history of TB, but who were in contact with bacterially active TB patients. Ancestry analysis was run on a set of 61 Ancestry-Informative Markers to estimate European, African, and Amerindian genetic ancestry using STRUCTURE v2.2. The TB group had significantly higher Amerindian ancestry in comparison with the control group, and significantly lower European ancestry. Amerindian ancestry in the 20-60% range was found to be the principal risk factor for increased susceptibility to TB. The results of the study indicate that Amerindian ancestry is an important risk factor for susceptibility to TB in the admixed population of the Brazilian Amazon region.

The manifestation of the COVID-19 varies from absence of symptoms to Severe Acute Respiratory Syndrome. The epidemiological data indicate that infection and mortality rates are greater in European populations in comparison with eastern Asians. To test if epidemiological patterns may be partly determined by human genetic variation, we investigated, by exomic and databank analyses, the variability found in the TMPRSS2 gene in populations from different continents, since this gene is fundamental to virus access into human cells. The functional variants revealed low diversity. The analyses of the variation in the modifiers of gene expression indicate that the European populations may have much higher levels of pulmonary expression of the TMPRSS2 gene and would be more vulnerable to infection by SARS-CoV-2. By contrast, the pulmonary expression of the TMPRSS2 may be reduced in the populations from East Asia, which implies that they are less susceptible to the virus infection and, these genetic features might also favor their better outcomes. The presented data, if confirmed, indicates a potential genetic contribution of TMPRSS2 to individual susceptibility to viral infection, and might also influence COVID-19 outcome.

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.

IntroductionThe 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.MethodsThe 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.ResultsFour 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.ConclusionOur findings indicate that Amerindian and admixed populations from northern Brazil have high frequencies of the NUDT15 haplotypes that alter the metabolism profile of thiopurines.

e15532 Background: Fluoropyrimidine-based treatments are still considered challenging due to the wide variability in efficacy and toxicity rates presented by patients. This variability can be explained, partially, by individual genetic differences that contribute significantly to the response of the drug, with 30% of patients experiencing severe toxicity related to dihydropyrimidine dehydrogenase (DPD) deficiency and 5-Fluorouracil (5-FU) metabolism. Methods: This study analyzed the exome of the main genes involved in the fluoropyrimidine metabolism pathway ( DPYD, TYMS / ENOSF1, MTHFR, CDA, CES2, and UGT1A1) in seven patient who developed fatal 5-FU toxicity diagnosed with gastric or colorectal adenocarcinoma and underwent fluoropyrimidine-based cancer treatment. The genotyping service was carried out at CEGEN-PRB3-ISCIII; it is supported by grant PT17/0019, of the PE I+D+i 2013-2016, funded by ISCIII and ERDF. Results: A total of 74 genetic polymorphisms were identified, 25 of which stand out due to their potential role in the safety of 5-FU administration. Eight variants are exclusive of the studied population (two found in the DPYD gene, two in the MHFR, one in the CES2, and three in the UGT1A1 gene) and 17 have already been associated with fluoropyrimidine efficacy and/or toxicity events: 10 of them are located in the DPYD gene (rs1801159, rs2297595, rs72728438, rs17376848, rs1801160, rs1801265, rs22447512, rs5568, rs56038477, rs56276561, and rs56293913), two in the intergenic region of the TYMS/ ENOSF1 genes (rs11280056 and rs699517), two in the MTHFR gene (rs1801131 and rs1801133) and three in the CDA gene (rs1048977, rs2072671, and rs3215400). Conclusions: The current study has allowed us to obtain a global profile of genetic variants in the pharmacokinetic and pharmacodynamic pathways of fluoropyrimidines in patients with high genetic miscegenation in the northern region of Brazil who have evolved to death due to the fatal toxicity resulting from 5-FU-based therapies. Keywords: Pharmacogenomics; Exome; 5-Fluorouracil; Drug toxicity; Brazil.

4056 Background: Epstein–Barr virus (EBV) discriminates a molecular group of gastric cancer (GC) that seems to have peculiar treatment responses and prognosis. Nevertheless, the gene expression pattern of such tumors needs additional investigations due to the heterogeneity of the tumor microbiome and the small number of studied samples. Biological networks analysis of gene expression patterns, in this complex scenario, might lead to the discovery of putative "hubs" genes, supposed to have important roles in cancer occurrence and consequences. This study aimed to explore the biological value of hub genes in EBV-positive gastric cancer patients. Methods: Fresh tumor samples collected during gastrectomies from individuals with gastric adenocarcinoma (n = 41, 59.0±11.0 years) were included. Gene expression of tumor samples was evaluated in the Illumina sequencing platform. A weighted correlation network analysis (WGCNA) was used to find highly correlated gene patterns. The gene's correlation to EBV status was also explored, including eight EBV positive and 33 EBV negative cases. Gene Ontology (GO) term enrichment was performed to predict the involved biological functions. The expression level of the hubs gene was measured by differential expression analysis. Results: A gene cluster including 636 genes able to discriminate EBV status (ρ = 0.65, p-value = 6e-05) was identified. GO analysis (padj 1 and padj< 0.05). The top hub genes were LAPTM5, PTPN22, C1QA, CD84, CD53, ADAMDEC1, DPYD, TYROBP, RARRES3, IFI16, CYBB, CMKLR1, PHF21A, GPNMB, and C1QC, according to cluster significance and gene expression level. In positive EBV-GC, all hub genes were overexpressed (FC 1.24 - 2.49) (Table). The average area under the ROC curve (AUC) for hub genes was 0.9 (0.84-0.99). Overexpression of LAPTM5 (p-value = 0.013) and DPYD (p-value =0.0065) and low expression of ADAMDEC1 (p-value = 0.05) were strongly related to poor survival outcome. Conclusions: EBV-positive status was correlated with overexpression of hub genes. Genes found in this investigation have high sensitivity and specificity to discriminate EBV status in GC. Some of them seem to be related to patients' survival, opening an avenue for future scientific explorations in this field. The biological network's approach may be a promising tool for mining target genes for potential clinical applications. [Table: see text]

e16056 Background: FLOT perioperative have emerged as a new standard for locally advanced gastric cancer (LAGC). Nevertheless, the molecular consequences of such therapy remain obscure. Aiming to investigate changes in the tumor transcriptional landscape in LAGC patients treated with FLOT, a comprehensive analysis of messenger RNA (mRNAs) and long noncoding RNA (lncRNAs) expression was developed using next-generation sequencing (NGS). Methods: Paired tumor and non-tumor fresh samples, including 17 patients with intestinal-type LAGC submitted to neoadjuvant FLOT treatment (treated group) and 13 who did not receive neoadjuvant therapy (untreated group), were sequenced and compared. Differential expression analyses were performed using the DESeq2 package. Criteria for differentially expressed (DE) lncRNAs and mRNAs were|Log2(Fold-Change)| > 2; and adjusted p-value < 0.05. In silico analyses were adopted to identify DE lncRNAs with transcription factors (TFs) and RNA-binding proteins (RPBs). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and gene ontology (GO) was also performed to elucidate these target proteins’ and mRNAs biological’s roles. Results: In tumor samples from the untreated group, 4443 mRNAs and 961 lncRNAs DE were found, in which 293 mRNAs and 148 lncRNAs accurately discriminated (the area under the curve ROC > 0.9) tumor and non-tumor tissues. Only 265 mRNAs and 29 lncRNAs DE were detected in treated patients, indicating that neoadjuvant therapy led to changes in expression patterns, making tumor tissues similar to non-tumor tissues. Subsequent analyzes identified that non-tumor tissues (treated vs. untreated) showed similar expression profiles. Among tumor samples, 34 mRNAs and 54 lncRNAs DE were found, in which 7 mRNAs and 16 lncRNAs can discriminate between treated and untreated tumors, indicating the effect of neoadjuvant treatment is predominant in the tumor. GO evaluation of genes was significant for 83 terms for biological process. The most annotated terms were the regulation of catalytic activity. We also observed that DE lncRNAs interact with TFs and RBPs were enriched in related cancer development and progression pathways, including transcriptional dysregulation and cellular senescence. Conclusions: Despite the need for further validation to better understand the transcriptional landscape related to neoadjuvant treatment, the present study highlights the functional relevance of lncRNAs in tumor biology and, mainly, shed light on the molecular effects of FLOT neoadjuvant treatment, that might help to guide future investigations aiming to establish personalized management of GC.

e15082 Background: Adverse drug reactions are an important cause of morbidity and mortality commonly found in different therapeutic regimens, particularly in oncologic. About 20-30% of these reactions are due to the individual genetic variability of patients. Pharmacogenomics focuses on the identification of genetic variants that influence drug efficacy, response, and/or toxicity by changes in pharmacokinetics/pharmacodynamics. Pharmacogenomic investigations are known to have a population bias. There is a gap in the accumulated about pharmacogenomic variants in poorly studied populations, such as the Amerindian population from the Brazilian Amazon region. The objective of this work is to describe the pharmacogenetic variability regarding 160 pharmacogenes involved in pharmacokinetic processes and biological pathways of different therapies, including oncology treatments, based on data obtained through complete exome sequencing of 64 individuals from different Amerindian groups of the Brazilian Amazon. Methods: The present study was approved by the National Committee for Ethics in Research and the Research Ethics Committee of the UFPA Tropical Medicine Center, under CAAE number 20654313.6.0000.5172. All participants signed a free-informed consent. The DNA extraction was performed using phenol-chloroform. Libraries were prepared using the Nextera Rapid Capture Exome and SureSelect Human All Exon V6 kits. Bioinformatic analysis was performed by ViVa software. Results: Our results show a total of 3,311 variants found in the study subjects. Of this, 167 are exclusive variants found in the Amerindians. Among these new variants, we found a non-synonymous coding variant in the DPYD gene with an allelic frequency of 3%, and variants with high allelic frequencies in intronic regions, which may regulate gene expression: MTHFR (5.56%), TYMS (11.5%) GSTT1 (54.1%), and three variants in the CYP2D6 gene with frequencies of 54%, 62.3%, and 65.6%. The DPYD is a pivotal gene involved with the efficacy of fluoropyrimidine-based treatment; the MTHFR and TYMS genes also participate in the biological pathways of these drugs, responsible for variation in response rates. The GSTT1 is a gene associated with platinum-based treatments, such as carboplatin and cisplatin. And, finally, CYP2D6 is one of the main pharmacogene described, involved in several drug schemes, including tamoxifen and gefitinib, used to treat breast and lung cancer, respectively. Conclusions: Understanding the diversity of genetic markers in Amazonian Amerindian is crucial to the implementation of pharmacogenomic-guided oncology treatment protocols, since pharmacogenomic data validated in other ancestral groups may not be fully applicable in these populations due to their unique genetic profile. Keywords: Exome, Native American populations, fluoropyrimidine, platinum-based drugs, tamoxifen, gefitinib.

e19025 Background: The MUC family includes several genes previously associated with carcinogenesis and it is associated with solid neoplasms such as those of the gastrointestinal tract. As far as we are aware, there are no studies relating MUC genes to acute lymphoblastic leukemia (ALL), and this type of cancer is 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 Brazilian Amazon, in a sample containing healthy Native Americans (NAM) and indigenous with ALL, comparing the frequency of polymorphisms between these two groups. Methods: The population was formed by 64 Amerindians from the Brazilian Amazon from 12 different ethnic groups, 5 of whom were diagnosed with ALL. We analyzed 16 genes from the MUC family (MUC1, MUC2, MUC3A, MUC4, MUC5AC, MUC5B, MUC6, MUC7, MUC12, MUC13, MUC15, MUC16, MUC17, MUC19, MUC20, MUC21) and found a total of 1858 variants. Results: After the quality filter, only 743 variants remained. Among them, we compared the frequency of each polymorphism in the LLA vs NAM group, which led to 77 variants with a significant difference, and, among these, we excluded those with LOW impact, resulting in 63. The 63 polymorphisms were distributed in 9 genes, concentrated especially in MUC 19 (n = 30) and MUC 3A (n = 18). Finally, 11 new variants were found in the NAM population. Conclusions: 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. Keywords: MUC family; ALL; Susceptibility; Native American Populations; Brazil.