Browsing by Author "Morales, Erik"

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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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    Development and internal validation of a multifactorial risk prediction model for gallbladder cancer in a high-incidence country
    (2023) Boekstegers, Felix; Scherer, Dominique; Barahona Ponce, Carol; Marcelain, Katherine; Garate-Calderon, Valentina; Waldenberger, Melanie; Morales, Erik; Rojas, Armando; Munoz, Cesar; Retamales, Javier; de Toro, Gonzalo; Barajas, Olga; Rivera, Maria Teresa; Cortes, Analia; Loader, Denisse; Saavedra, Javiera; Gutierrez, Lorena; Ortega, Alejandro; Bertran, Maria Enriqueta; Bartolotti, Leonardo; Gabler, Fernando; Campos, Monica; Alvarado, Juan; Moisan, Fabricio; Spencer, Loreto; Nervi, Bruno; Carvajal-Hausdorf, Daniel; Losada, Hector; Almau, Mauricio; Fernandez, Plinio; Olloquequi, Jordi; Fuentes-Guajardo, Macarena; Gonzalez-Jose, Rolando; Bortolini, Maria Catira; Acuna-Alonzo, Victor; Gallo, Carla; Linares, Andres Ruiz; Rothhammer, Francisco; Lorenzo Bermejo, Justo
    Since 2006, Chile has been implementing a gallbladder cancer (GBC) prevention program based on prophylactic cholecystectomy for gallstone patients aged 35 to 49 years. The effectiveness of this prevention program has not yet been comprehensively evaluated. We conducted a retrospective study of 473 Chilean GBC patients and 2137 population-based controls to develop and internally validate three GBC risk prediction models. The Baseline Model accounted for gallstones while adjusting for sex and birth year. Enhanced Model I also included the non-genetic risk factors: body mass index, educational level, Mapuche surnames, number of children and family history of GBC. Enhanced Model II further included Mapuche ancestry and the genotype for rs17209837. Multiple Cox regression was applied to assess the predictive performance, quantified by the area under the precision-recall curve (AUC-PRC) and the number of cholecystectomies needed (NCN) to prevent one case of GBC at age 70 years. The AUC-PRC for the Baseline Model (0.44%, 95%CI 0.42-0.46) increased by 0.22 (95%CI 0.15-0.29) when non-genetic factors were included, and by 0.25 (95%CI 0.20-0.30) when incorporating non-genetic and genetic factors. The overall NCN for Chileans with gallstones (115, 95%CI 104-131) decreased to 92 (95%CI 60-128) for Chileans with a higher risk than the median according to Enhanced Model I, and to 80 (95%CI 59-110) according to Enhanced Model II. In conclusion, age, sex and gallstones are strong risk factors for GBC, but consideration of other non-genetic factors and individual genotype data improves risk prediction and may optimize allocation of financial resources and surgical capacity.
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    Identification of Circulating lncRNAs Associated with Gallbladder Cancer Risk by Tissue-Based Preselection, Cis-eQTL Validation, and Analysis of Association with Genotype-Based Expression
    (2022) Blandino, Alice; Scherer, Dominique; Rounge, Trine B.; Umu, Sinan U.; Boekstegers, Felix; Barahona Ponce, Carol; Marcelain, Katherine; Garate-Calderon, Valentina; Waldenberger, Melanie; Morales, Erik; Rojas, Armando; Munoz, Cesar; Retamales, Javier; de Toro, Gonzalo; Barajas, Olga; Rivera, Maria Teresa; Cortes, Analia; Loader, Denisse; Saavedra, Javiera; Gutierrez, Lorena; Ortega, Alejandro; Bertran, Maria Enriqueta; Gabler, Fernando; Campos, Monica; Alvarado, Juan; Moisan, Fabrizio; Spencer, Loreto; Nervi, Bruno; Carvajal-Hausdorf, Daniel E.; Losada, Hector; Almau, Mauricio; Fernandez, Plinio; Gallegos, Ivan; Olloquequi, Jordi; Fuentes-Guajardo, Macarena; Gonzalez-Jose, Rolando; Bortolini, Maria Catira; Gallo, Carla; Linares, Andres Ruiz; Rothhammer, Francisco; Lorenzo Bermejo, Justo
    Simple Summary Gallbladder cancer (GBC) is an aggressive disease with poor prognosis that urgently needs risk biomarkers for prevention. Long noncoding RNAs (lncRNAs) have been linked to various types of cancer and have good potential as circulating biomarkers. Prediction of lncRNA expression based on genotype data may contribute to quantify individual GBC risk even without direct lncRNA expression measurement. In this study, we investigate the relationship between GBC risk and genotype-based expression of circulating lncRNAs. Long noncoding RNAs (lncRNAs) play key roles in cell processes and are good candidates for cancer risk prediction. Few studies have investigated the association between individual genotypes and lncRNA expression. Here we integrate three separate datasets with information on lncRNA expression only, both lncRNA expression and genotype, and genotype information only to identify circulating lncRNAs associated with the risk of gallbladder cancer (GBC) using robust linear and logistic regression techniques. In the first dataset, we preselect lncRNAs based on expression changes along the sequence "gallstones -> dysplasia -> GBC". In the second dataset, we validate associations between genetic variants and serum expression levels of the preselected lncRNAs (cis-lncRNA-eQTLs) and build lncRNA expression prediction models. In the third dataset, we predict serum lncRNA expression based on individual genotypes and assess the association between genotype-based expression and GBC risk. AC084082.3 and LINC00662 showed increasing expression levels (p-value = 0.009), while C22orf34 expression decreased in the sequence from gallstones to GBC (p-value = 0.04). We identified and validated two cis-LINC00662-eQTLs (r(2) = 0.26) and three cis-C22orf34-eQTLs (r(2) = 0.24). Only LINC00662 showed a genotyped-based serum expression associated with GBC risk (OR = 1.25 per log2 expression unit, 95% CI 1.04-1.52, p-value = 0.02). Our results suggest that preselection of lncRNAs based on tissue samples and exploitation of cis-lncRNA-eQTLs may facilitate the identification of circulating noncoding RNAs linked to cancer risk.
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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.