Browsing by Author "Bermejo, Justo Lorenzo"

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    Cholecystectomy and digestive cancer in Chile: Complementary results from interrupted time series and aggregated data analyses
    (2025) Gonzalez, Constanza; Garcia-Perez, Alfonso; Nervi, Bruno; Munoz, Cesar; Morales, Erik; Losada, Hector; Merino-Pereira, Gina; Rothhammer, Francisco; Bermejo, Justo Lorenzo
    Gallbladder cancer (GBC) mortality in Chile is among the highest worldwide. In 2006, the Chilean government launched a programme guaranteeing access to gallbladder surgery (cholecystectomy) for patients aged 35-49 years. We evaluated the impact of this programme on digestive cancer mortality. After conducting an interrupted time series analysis of hospitalisation and mortality data from 2002 to 2018 publicly available from the Chilean Department of Health Statistics and Information, we calculated the change in the proportion of individuals without gallbladder since 10 years. We then estimated age, gender, region, and calendar-year standardised mortality ratios (SMRs) as a function of the change in the proportion of individuals without gallbladder. The cholecystectomy rate increased by 45 operations per 100,000 persons per year (95%CI 19-72) after the introduction of the health programme. Each 1% increase in the proportion of individuals without gallbladder since 10 years was associated with a 0.73% decrease in GBC mortality (95% CI -1.05% to -0.38%), but the negative correlation was limited to women, southern Chile and age over 60. We also found decreasing mortality rates for extrahepatic bile duct, liver, oesophageal and stomach cancer with increasing proportions of individuals without gallbladder. To conclude, 12 years after its inception, the Chilean cholecystectomy programme has markedly and heterogeneously changed cholecystectomy rates. Results based on aggregate data indicate a negative correlation between the proportion of individuals without gallbladder and mortality due to gallbladder and other digestive cancers, which requires validation using individual-level longitudinal data to reduce the potential impact of ecological bias.
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    Gallbladder Cancer Risk and Indigenous South American Mapuche Ancestry: Instrumental Variable Analysis Using Ancestry-Informative Markers
    (2023) Zollner, Linda; Boekstegers, Felix; Barahona Ponce, Carol; Scherer, Dominique; Marcelain, Katherine; Gárate-Calderón, Valentina; Waldenberger, Melanie; Morales Mejías, Erik; Rojas, Armando; Muñoz, César; Retamales, Javier; Toro, Gonzalo De; Vera Kortmann, Allan; Barajas, Olga; Rivera, María Teresa; Cortés, Analía; Loader, Denisse; Saavedra, Javiera; Gutiérrez, Lorena; Ortega, Alejandro; Bertrán, María Enriqueta; Bartolotti, Leonardo; Gabler, Fernando; Campos, Mónica; Alvarado, Juan; Moisán, Fabricio; Spencer, María Loreto; Nervi Nattero, Bruno; Carvajal-Hausdorf, Daniel; Losada, Héctor; Almau, Mauricio; Fernández, Plinio; Olloquequi, Jordi; Carter, Alice R.; Miquel P., Juan Francisco; Bustos, Bernabé I.; Fuentes Guajardo, Macarena; Gonzalez-Jose, Rolando; Bortolini, Maria Cátira; Acuña-Alonzo, Victor; Gallo, Carla; Ruiz Linares, Andrés; Rothhammer, Francisco; Bermejo, Justo Lorenzo
    A strong association between the proportion of indigenous South American Mapuche ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest indigenous people in Chile. We set out to assess the confounding-free effect of the individual proportion of Mapuche ancestry on GBC risk and to investigate the mediating effects of gallstone disease and body mass index (BMI) on this association. Genetic markers of Mapuche ancestry were selected based on the informativeness for assignment measure, and then used as instrumental variables in two-sample Mendelian randomization analyses and complementary sensitivity analyses. Results suggested a putatively causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% per 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.7 × 10−5) and also on gallstone disease (3.6% IVW risk increase, 95% CI 3.1% to 4.0%), pointing to a mediating effect of gallstones on the association between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative effect on BMI (IVW estimate −0.006 kg/m2, 95% CI −0.009 to −0.003). The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between the individual proportion of Mapuche ancestry and GBC risk previously noted in observational studies appears to be free of confounding, primary and secondary prevention strategies that consider genetic ancestry could be particularly efficient.
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    Integrative molecular characterisation of gallbladder cancer reveals micro-environment-associated subtypes
    (2021) Nepal, Chirag; Zhu, Bin; O'Rourke, Colm J.; Bhatt, Deepak Kumar; Lee, Donghyuk; Song, Lei; Wang, Difei; Van Dyke, Alison L.; Choo-Wosoba, Hyoyoung; Liu, Zhiwei; Hildesheim, Allan; Goldstein, Alisa M.; Dean, Michael; LaFuente-Barquero, Juan; Lawrence, Scott; Mutreja, Karun; Olanich, Mary E.; Bermejo, Justo Lorenzo; Ferreccio, Catterina; Roa, Juan Carlos; Rashid, Asif; Hsing, Ann W.; Gao, Yu-Tang; Chanock, Stephen J.; Araya, Juan Carlos; Andersen, Jesper B.; Koshiol, Jill
    Background & Aims: Gallbladder cancer (GBC) is the most common type of biliary tract cancer, but the molecular mechanisms involved in gallbladder carcinogenesis remain poorly understood. In this study, we applied integrative genomics approaches to characterise GBC and explore molecular subtypes associated with patient survival. Methods: We profiled the mutational landscape of GBC tumours (whole-exome sequencing on 92, targeted sequencing on 98, in total 190 patients). In a subset (n = 45), we interrogated the matched transcriptomes, DNA methylomes, and somatic copy number alterations. We explored molecular subtypes identified through clustering tumours by genes whose expression was associated with survival in 47 tumours and validated subtypes on 34 publicly available GBC cases. Results: Exome analysis revealed TP53was themostmutated gene. The overallmutation ratewas low(median 0.82Mut/Mb). APOBECmediated mutational signatures were more common in tumours with higher mutational burden. Aflatoxin-related signatures tended to be highly clonal (present in >-50% of cancer cells). Transcriptome-wide survival association analysis revealed a 95gene signature that stratified all GBC patients into 3 subtypes that suggested an association with overall survival post-resection. The 2 poor-survival subtypes were associated with adverse clinicopathologic features (advanced stage, pN1, pM1), immunosuppressive micro-environments (myeloid-derived suppressor cell accumulation, extensive desmoplasia, hypoxia) and T cell dysfunction, whereas the good-survival subtype showed the opposite features. Conclusion: These data suggest that the tumour microenvironment and immune profiles could play an important role in gallbladder carcinogenesis and should be evaluated in future clinical studies, along with mutational profiles. Lay summary: Gallbladder cancer is highly fatal, and its causes are poorly understood. We evaluated gallbladder tumours to see if there were differences between tumours in genetic information such as DNA and RNA. We found evidence of aflatoxin exposure in these tumours, and immune cells surrounding the tumours were associated with survival. Published by Elsevier B.V. on behalf of European Association for the Study of the Liver.
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    PRDM15 Is Associated with Risk of Chronic Obstructive Pulmonary Disease in a Rural Population in Chile
    (KARGER, 2020) Hosgood, H. Dean, III; Diaz Pena, Roberto; Blansky, Deanna; Jaime, Sergio; Parra, Viviana; Boekstegers, Felix; Bermejo, Justo Lorenzo; Garcia Valero, Jose; Montes, Juan F.; Valdivia, Gonzalo; Miravitlles, Marc; Agusti, Alvar; Silva, Rafael S.; Olloquequi, Jordi
    Background: Genome-wide association studies (GWAS) have accelerated our understanding of the genetic underpinnings of chronic obstructive pulmonary disease (COPD); however, GWAS populations have typically consisted of European descent, with similar to 1% of Latin American ancestry. Objective: To overcome this limitation, we conducted a GWAS in a rural Chilean population with increased COPD risk to investigate genetic variation of COPD risk in this understudied minority population. Method: We carried out a case-control study of 214 COPD patients (defined by the GOLD criteria) and 193 healthy controls in Talca, Chile. DNA was extracted from venous blood and genotyped on the Illumina Global Screening Array (n = 754,159 markers). After exclusion based on Hardy-Weinberg equilibrium (p <= 0.001), call rates (<95%), and minor allele frequencies (<0.5%) in controls, 455,564 markers were available for logistic regression. Results: PRDM15 rs1054761 C allele (p = 2.22 x 10(-7)) was associated with decreased COPD risk. Three PRDM15 SNPs located on chromosome 21 were significantly associated with COPD risk (p < 10(-6)). Two of these SNPs, rs1054761 and rs4075967, were located on a noncoding transcript variant region of the gene. Conclusion: PRDM15 overexpression may play a role in the B-cell dysregulation in COPD pathogenesis. To the best of our knowledge, the association between PRDM15 and COPD risk was not previously found in GWAS studies in largely European populations, highlighting the importance of investigating novel variants associated with COPD risk among ethnically diverse populations.
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    Subtypes of Native American ancestry and leading causes of death: Mapuche ancestry-specific associations with gallbladder cancer risk in Chile
    (2017) Bermejo, Justo Lorenzo; Boekstegers, Felix; González Silos, Rosa; Marcelain, Katherine; Báez Benavides, Pablo; Barahona Ponce, Carol; Müller, Bettina; Ferreccio Readi, Catterina; Koshiol, Jill; Fischer, Christine
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    Validation of an NGS Panel Designed for Detection of Actionable Mutations in Tumors Common in Latin America
    (2021) Salvo, Mauricio; Gonzalez-Feliu, Evelin; Toro, Jessica; Gallegos, Ivan; Maureira, Ignacio; Miranda-Gonzalez, Nicolas; Barajas, Olga; Bustamante, Eva; Ahumada, Monica; Colombo, Alicia; Armisen, Ricardo; Villaman, Camilo; Ibanez, Carolina; Bravo, Maria Loreto; Sanhueza, Veronica; Spencer, M. Loreto; de Toro, Gonzalo; Morales, Erik; Bizama, Carolina; Garcia, Patricia; Carrasco, Ana Maria; Gutierrez, Lorena; Bermejo, Justo Lorenzo; Verdugo, Ricardo A.; Marcelain, Katherine
    Next-generation sequencing (NGS) is progressively being used in clinical practice. However, several barriers preclude using this technology for precision oncology in most Latin American countries. To overcome some of these barriers, we have designed a 25-gene panel that contains predictive biomarkers for most current and near-future available therapies in Chile and Latin America. Library preparation was optimized to account for low DNA integrity observed in formalin-fixed paraffin-embedded tissue. The workflow includes an automated bioinformatic pipeline that accounts for the underrepresentation of Latin Americans in genome databases. The panel detected small insertions, deletions, and single nucleotide variants down to allelic frequencies of 0.05 with high sensitivity, specificity, and reproducibility. The workflow was validated in 272 clinical samples from several solid tumor types, including gallbladder (GBC). More than 50 biomarkers were detected in these samples, mainly in BRCA1/2, KRAS, and PIK3CA genes. In GBC, biomarkers for PARP, EGFR, PIK3CA, mTOR, and Hedgehog signaling inhibitors were found. Thus, this small NGS panel is an accurate and sensitive method that may constitute a more cost-efficient alternative to multiple non-NGS assays and costly, large NGS panels. This kind of streamlined assay with automated bioinformatics analysis may facilitate the implementation of precision medicine in Latin America.