Challenges of diagnostic genomics in Latin America

Germline Genetic Variants in Cancer Predisposition Genes in Patients From Latin America and the Caribbean

The importance of having region-specific data when planning health interventions has become evident in recent years. Nonetheless, several world regions, including Latin America and the Caribbean (LAC), still face significant challenges. These regions need to develop strategies specifically designed to consider the inherent characteristics of their population composite and sociodemographic characteristics. More than 20% of the global cancer incidence arises in LAC. Yet, treatment, prevention, and follow-up guidelines in the area are frequently based on studies that mainly include patients from North America, Europe, and Asia. As personalized approaches become ubiquitous in medical practice, the amount of information emerging from LAC has risen considerably. In this review, we seek to present a comprehensive summary of the frequency of germline genetic variants in hereditary cancer syndromes in patients from LAC. The data highlight relevant differences in variants associated with LAC patients, including founder and recurrent variants, while showcasing potential features that might be relevant in oncology practices.

Beyond tobacco: genomic disparities in lung cancer between smokers and never-smokers

BACKGROUND

Tobacco use is one of the main risk factors for Lung Cancer (LC) development. However, about 10-20% of those diagnosed with the disease are never-smokers. For Non-Small Cell Lung Cancer (NSCLC) there are clear differences in both the clinical presentation and the tumor genomic profiles between smokers and never-smokers. For example, the Lung Adenocarcinoma (LUAD) histological subtype in never-smokers is predominately found in young women of European, North American, and Asian descent. While the clinical presentation and tumor genomic profiles of smokers have been widely examined, never-smokers are usually underrepresented, especially those of a Latin American (LA) background. In this work, we characterize, for the first time, the difference in the genomic profiles between smokers and never-smokers LC patients from Chile.

METHODS

We conduct a comparison by smoking status in the frequencies of genomic alterations (GAs) including somatic mutations and structural variants (fusions) in a total of 10 clinically relevant genes, including the eight most common actionable genes for LC (EGFR, KRAS, ALK, MET, BRAF, RET, ERBB2, and ROS1) and two established driver genes for malignancies other than LC (PIK3CA and MAP2K1). Study participants were grouped as either smokers (current and former, n = 473) or never-smokers (n = 200) according to self-report tobacco use at enrollment.

RESULTS

Our findings indicate a higher overall GA frequency for never-smokers compared to smokers (58 vs. 45.7, p-value < 0.01) with the genes EGFR, KRAS, and PIK3CA displaying the highest prevalence while ERBB2, RET, and ROS1 the lowest. Never-smokers present higher frequencies in seven out of the 10 genes; however, smokers harbor a more complex genomic profile. The clearest differences between groups are seen for EGFR (15.6 vs. 21.5, p-value: < 0.01), PIK3CA (6.8 vs 9.5) and ALK (3.2 vs 7.5) in favor of never-smokers, and KRAS (16.3 vs. 11.5) and MAP2K1 (6.6 vs. 3.5) in favor of smokers. Alterations in these genes are comprised almost exclusively by somatic mutations in EGFR and mainly by fusions in ALK, and only by mutations in PIK3CA, KRAS and MAP2K1.

CONCLUSIONS

We found clear differences in the genomic landscape by smoking status in LUAD patients from Chile, with potential implications for clinical management in these limited-resource settings.

Multilocus inherited neoplasia allele syndrome: report of uncommon combinations between CHEK2/ATM and BRCA1/CDKN2A genes

Background

Multilocus inherited neoplasia allelic syndrome (MINAS) is a recently coined term that describes the coexistence of two or more pathogenic variants (PVs) in cancer susceptibility genes (CSGs) in a single individual.

Case presentation

This article presents two cases of MINAS due to rare CSG combinations. The first was a 37-year-old woman carrying PVs in the mutated ataxia telangiectasia (ATM) and CHEK2 genes, with HER-2 positive unilateral breast cancer at 29. The second was a 53-year-old woman carrying PVs in the BRCA1 and CDKN2A genes, who presented with triple-negative breast cancer at 51. We describe their family history and treatment, where the lack of evidence for personalised management becomes evident.

Conclusion

Predicting the phenotypic effect of harbouring two variants in CSG is challenging. It is essential to encourage the notification of other cases and carry out functional studies to establish specific risks for affected individuals to develop personalised follow-up guidelines to reduce the associated morbimortality.

Prospective Study of Homologous Recombination Repair Gene Mutation Prevalence in Patients With Advanced Prostate Cancer From Latin America: Challenges and Future Approaches

PURPOSE

The prevalence of homologous recombination repair gene mutations (HRRm) in patients with metastatic castration-resistant prostate cancer (mCRPC) in Latin America and the Caribbean (LAC) is unknown. Prevalence of homologous Recombination repair (HRR) gene mutatiOns in patientS with metastatic castration resistant ProstatE Cancer in LaTin America (PROSPECT) aimed to determine this prevalence and to describe the demographic and clinical characteristics of the participants.

MATERIALS AND METHODS

This was a prospective, cross-sectional, multicenter study across 11 cancer centers in seven LAC countries. After informed consent, all eligible participants underwent genomic testing by provided blood samples for germline HRR testing; they also provided PC tissue blocks if available for somatic HRR testing.

RESULTS

Between April 2021 and April 2022, 387 patients (median age, 70 years [49-89], 94.3% Eastern Cooperative Oncology Group 0-1) with mCRPC were enrolled in the study. Almost 40% of them had a family history of cancer, and the overall time from their initial PC and mCRPC diagnosis was 3 years and 1 year, respectively. The overall prevalence of germline HRRm was 4.2%. The mutations detected included the genes CHEK2 (n = 4, 1%), ATM (n = 3, 0.8%), BRCA2 (n = 3, 0.8%), BRIP1 (n = 2, 0.5%), RAD51B (n = 2, 0.5%), BRCA1 (n = 1, 0.3%), and MRE11 (n = 1, 0.3%). The prevalence of somatic HRRm could not be assessed because of high HRR testing failure rates (79%, 199/251) associated with insufficient DNA, absence of tumor cells, and poor-quality DNA.

CONCLUSION

Despite the study's limitations, to our knowledge, PROSPECT was the first attempt to describe the prevalence of HRRm in patients with PC from LAC. Notably, the germline HRRm prevalence in this study was inferior to that observed in North American and European populations. The somatic HRR testing barriers identified are being addressed by several projects to improve access to HRR testing and biomarker-based therapies in LAC.

Discovery of novel genetic syndromes in Latin America: Opportunities and challenges

Latin America (LatAm) has a rich and historically significant role in delineating both novel and well-documented genetic disorders. However, the ongoing advancements in the field of human genetics pose challenges to the relatively slow adaption of LatAm in the field. Here, we describe past and present contributions of LatAm to the discovery of novel genetic disorders, often referred as novel gene-disease associations (NGDA). We also describe the current methodologies for discovery of NGDA, taking into account the latest developments in genomics. We provide an overview of opportunities and challenges for NGDA research in LatAm considering the steps currently performed to identify and validate such associations. Given the multiple and diverse needs of populations and countries in LatAm, it is imperative to foster collaborations amongst patients, indigenous people, clinicians and scientists. Such collaborative effort is essential for sustaining and enhancing the LatAm´s contributions to the field of NGDA.

Management of radioiodine refractory differentiated thyroid cancer: the Latin American perspective

Radioiodine (RAI) refractory differentiated thyroid cancer is an uncommon and challenging situation that requires a multidisciplinary approach to therapeutic strategies. The definition of RAI-refractoriness is usually a clear situation in specialized centers. However, the right moment for initiation of multikinase inhibitors (MKI), the time and availability for genomic testing, and the possibility of prescribing MKI and selective kinase inhibitors differ worldwide.Latin America (LA) refers to the territories of the world that stretch across two regions: North America (including Central America and the Caribbean) and South America, containing 8.5% of the world's population. In this manuscript, we critically review the current standard approach recommended for patients with RAI refractory differentiated thyroid cancer, emphasizing the challenges faced in LA. To achieve this objective, the Latin American Thyroid Society (LATS) convened a panel of experts from Brazil, Argentina, Chile, and Colombia. Access to MKI compounds continues to be a challenge in all LA countries. This is true not only for MKI but also for the new selective tyrosine kinase inhibitor, which will also require genomic testing, that is not widely available. Thus, as precision medicine advances, significant disparities will be made more evident, and despite efforts to improve coverage and reimbursement, molecular-based precision medicine remains inaccessible to most of the LA population. Efforts should be undertaken to alleviate the discrepancies between the current state-of-the-art care for RAI-refractory differentiated thyroid cancer and the present situation in Latin America.

Historical evolution of cancer genomics research in Latin America: a comprehensive visual and bibliometric analysis until 2023

Background: Cancer genomics, as an interdisciplinary research area within the Global Cancer Research agenda, genomics and precision medicine, its important in research and clinical practice in Latin America. To date, there has been no study investigating evolution of this area in this region. The aim of this study was to evaluate for first time, the historical evolution of cancer genomics research in Latin America. Methods: Bibliometric cross-sectional study of documents on cancer genomics published by Latin American authors until 2023 in Scopus was performed. Statistical and visual analysis was performed with R programming language. Results: A total of 1534 documents were obtained. The first document of cancer genomics research was published in 1997, marking the inception of a 26-year evaluation period that extended until 2023. Among the documents, 74.3% (n = 1140) constituted original articles, followed by 22.7% (n = 349) classified as reviews. International collaboration was observed in 6.5% (n = 100) of the articles. Within the compilation of the ten most prolific authors in this region, 90% of them are from Brazil. This observed pattern extends to affiliations as well, wherein the Universidade de São Paulo emerges as the most active institution (n = 255 documents). This arrangement firmly establishes Brazil's prominence as the preeminent country in the region concerning cancer genomics research, showcasing robust collaboration networks both regionally and intercontinentally. An important transition in the studied hot topics over the last 20 years was identified, from the exploration of the human genome and the characterization of genomic and proteomic cancer profiles (1997-2010) to an in-depth investigation of cancer stem cells and personalized medicine (2011-2023). Among the array of cancer types under study, predominant attention has been directed towards breast, lung, prostate, and leukemia. Conclusion: Over the course of the past 26 years, a favorable and notable evolution has characterized cancer genomics research within Latin America, with Brazil leading the way, which possess a robust network of regional and intercontinental collaboration. Furthermore, the lines of research and hot topics have change in harmony with the region's objectives, strategies, and requisites.

Implementing precision oncology in Latin America to improve patient outcomes: the status quo and a call to action for key stakeholders and decision-makers

Background

The advent of precision oncology (PO) has revolutionised diagnostic and follow up strategies and improved clinical outcomes for cancer patients. However, socio-economic inequalities in the level of implementation of PO in different countries is a prevailing issue. To improve this situation, the Latin America Patients Academy has gathered the recommendations of healthcare professionals and social civil members experienced in cancer management from Mexico, Guatemala, Costa Rica, Dominican Republic, Panama, Colombia, Chile, Ecuador, Peru and Argentina regarding the areas that need to be prioritised to improve the access to PO in Latin American (LATAM) countries.

Methods

This manuscript is the culmination of a series of educational campaigns and panel discussion aimed at improving the implementations of PO in LATAM that took place from June 2021 to January 2022.

The status of PO in Latin America

the level of PO implementation is generally low with some exceptions. The number of clinical trials and articles published with keywords related to PO from LATAM countries is drastically lower than in Europe and the United States. Despite sharing many complex challenges, progress is taking place in some countries in the region.

Focus areas defined by the expert panel

The expert panel determined the areas of PO that should be improved by LATAM countries to improve its implementation through cancer care plans, educational programs and collaborative strategies. These initiatives should increase awareness about PO in the region and eventually improve cancer control in the region.

Molecular Tumor Board Improves Outcomes for Hispanic Patients With Advanced Solid Tumors

PURPOSE

Multidisciplinary molecular tumor boards (MTBs) decode complex genomic data into clinical recommendations. Although MTBs are well-established in the oncology practice in developed countries, this strategy needs to be better explored in developing countries. Herein, we describe the possible benefits and limitations of the first MTB established in Colombia.

METHODS

Demographic, clinical, and genomic information was collected between August 2020 and November 2021. By mid-2020, an MTB strategy was created to discuss clinical cases with one or more genomic alterations identified by next-generation sequencing using an open-access virtual platform. We characterized the patient population as benefiting from the recommended treatment option. We assessed the benefits and access to available targeted therapies that have the potential to change clinical management by making recommendations to treating oncologists on the basis of genomic profiling. However, we did not assess the treatment oncologists' compliance with MTB recommendations because they were not intended to replace clinical judgment/standard of care.

RESULTS

A total of 146 patients were included in the discussions of the MTB. The median age was 59 years, and 59.6% were women. Genomic results prompting a change in therapeutic decisions were obtained in 53.1% of patients (95% CI, 44.9 to 61.3). The most prevalent malignancy was non-small-cell lung cancer (51%). Other malignancies represented 60%, 50%, and 30% of patients with soft-tissue sarcomas, brain tumors, and breast cancer, respectively.

CONCLUSION

Using an open-access virtual platform, MTBs were feasible in low- and middle-income countries on the basis of the capability to provide the benefits and access to available targeted therapies that are not standard of care. Furthermore, MTB recommendations were made available to the treating oncologist in different locations across Colombia, providing the option to modify clinical management in most of these patients.

Detection of NTRK gene fusions in solid tumors: recommendations from a Latin American group of oncologists and pathologists

NTRK gene fusions have been detected in more than 25 types of tumors and their prevalence is approximately 0.3% in solid tumors. This low prevalence makes identifying patients who could benefit from TRK inhibitors a considerable challenge. Furthermore, while numerous papers on the evaluation of NTRK fusion genes are available, not all countries have guidelines that are suitable for their setting, as is the case with Latin America. Therefore, a group of oncologists and pathologists from several countries in Latin America (Argentina, Chile, Ecuador, Mexico, Peru and Uruguay) met to discuss and reach consensus on how to identify patients with NTRK gene fusions in solid tumors. To do so, they developed a practical algorithm, considering their specific situation and limitations.

Germline DNA Repair Genes Pathogenic Variants Among Mexican Patients With Prostate Cancer

BACKGROUND

Early identification of germline mutation carriers may be relevant for the optimal management of prostate cancer and to inform cancer risk in relatives. However, population minorities have limited access to genetic testing. The aim of this study was to describe the frequency of DNA repair gene pathogenic variants (PVs) among Mexican men with prostate cancer referred for Genomic Cancer Risk Assessment and testing.

METHODS

Patients diagnosed with prostate cancer who meet criteria for genetic testing and enrolled in the Clinical Cancer Genomics Community Research Network at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán in Mexico City were included. Descriptive statistics were performed using frequency and proportions for categorical variables and median and range for quantitative variables. X2 and t test were used for group comparisons.

RESULTS

A total of 199 men were enrolled, median age at diagnosis was 66 (range 44-88) years; 45% were de novo metastatic and 44% were high- very high and 10% were intermediate risk group. Four (2%) had a pathogenic germline variant; one each of the following genes: ATM, CHEK2, BRIP1, and MUTYH (all monoallelic). Younger men at diagnosis were more likely to carry a PV than older age at diagnosis (56.7 vs. 66.4 years, P = .01).

CONCLUSION

Our results showed a low prevalence of known prostate cancer associated PVs and no BRCA PVs in Mexican men with prostate cancer. This suggests that the genetic and/or epidemiologic risk factors for prostate cancer are not well characterized in this specific population.

Access disparities and underutilization of germline genetic testing in Chilean breast cancer patients

PURPOSE

Latin American reports on genetic cancer risk assessments are scarce. In Chile, current breast cancer (BC) guidelines do not define strategies for germline genetic testing. Our study sought to quantify the disparities in access to genetic testing in Chilean BC patients, according to international standards and their clinical characteristics to explore improvement strategies.

METHODS

Retrospective analysis of invasive BC databases including patients treated in a Public Hospital (PH) and in an Academic Private Center (AC) in Santiago, Chile between 2012 and 2021.

RESULTS

Of 5438 BC patients, 3955 had enough data for National Comprehensive Cancer Network (NCCN) categorization. From these, 1911 (48.3%) fulfilled NCCN criteria for germline testing, of whom, 300 were tested for germline mutations and 268 with multigene panels. A total of 65 pathogenic variants were found in this subset. As expected, BRCA1/2 mutations were the most frequent (17.7%). Access to genetic testing was higher in AC versus PH (19.6% vs. 10.3%, p = 0.0001). Other variables associated with germline genetic testing were BC diagnosis after 2018, being 45 years old or younger at diagnosis, BC family history (FH), FH of ovarian cancer, non-metastatic disease, and triple-negative subtype.

CONCLUSION

In our cohort, 15% of BC patients who met NCCN criteria for germline testing were effectively tested. This percentage was even lower at the PH. Current recommendations encourage universal genetic testing for BC patients; however, our findings suggest that Chile is far from reaching such a goal and national guidelines in this regard are urgently needed. To our knowledge, this is the first study of its kind in Chile and Latin America.

Current landscape and future directions of synthetic biology in South America

Synthetic biology (SynBio) is a rapidly advancing multidisciplinary field in which South American countries such as Chile, Argentina, and Brazil have made notable contributions and have established leadership positions in the region. In recent years, efforts have strengthened SynBio in the rest of the countries, and although progress is significant, growth has not matched that of the aforementioned countries. Initiatives such as iGEM and TECNOx have introduced students and researchers from various countries to the foundations of SynBio. Several factors have hindered progress in the field, including scarce funding from both public and private sources for synthetic biology projects, an underdeveloped biotech industry, and a lack of policies to promote bio-innovation. However, open science initiatives such as the DIY movement and OSHW have helped to alleviate some of these challenges. Similarly, the abundance of natural resources and biodiversity make South America an attractive location to invest in and develop SynBio projects.

Framework for Adoption of Next-Generation Sequencing (NGS) Globally in the Oncology Area

Radical new possibilities of improved treatment of cancer are on offer from an advanced medical technology already demonstrating its significance: next-generation sequencing (NGS). This refined testing provides unprecedentedly precise diagnoses and permits the use of focused and highly personalized treatments. However, across regions globally, many cancer patients will continue to be denied the benefits of NGS as long as some of the yawning gaps in its implementation remain unattended. The challenges at the regional and national levels are linked because putting the solutions into effect is highly dependent on cooperation between regional- and national-level cooperation, which could be hindered by shortfalls in interpretation or understanding. The aim of the paper was to define and explore the necessary conditions for NGS and make recommendations for effective implementation based on extensive exchanges with policy makers and stakeholders. As a result, the European Alliance for Personalised Medicine (EAPM) developed a maturity framework structured around demand-side and supply-side issues to enable interested stakeholders in different countries to self-evaluate according to a common matrix. A questionnaire was designed to identify the current status of NGS implementation, and it was submitted to different experts in different institutions globally. This revealed significant variability in the different aspects of NGS uptake. Within different regions globally, to ensure those conditions are right, this can be improved by linking efforts made at the national level, where patients have needs and where care is delivered, and at the global level, where major policy initiatives in the health field are underway or in preparation, many of which offer direct or indirect pathways for building those conditions. In addition, in a period when consensus is still incomplete and catching up is needed at a political level to ensure rational allocation of resources-even within individual countries-to enable the best ways to make the necessary provisions for NGS, a key recommendation is to examine where closer links between national and regional actions could complement, support, and mutually reinforce efforts to improve the situation for patients.

Survival Outcomes of Metastatic Non-small Cell Lung Cancer Patients With Limited Access to Immunotherapy and Targeted Therapy in a Cancer Center of a Low- and Middle-Income Country

OBJECTIVE

To describe the survival outcomes of metastatic non-small cell lung cancer patients with limited access to immunotherapy and targeted therapy in a cancer reference center in Colombia.

METHODS

A retrospective analysis of metastatic non-small cell lung cancer patients treated between 2013 and 2018 was performed, majority diagnosed with adenocarcinoma. It was carried out in a public cancer reference center that provides care to patients of low and middle socioeconomic status. Overall survival and progression-free survival were evaluated by Kaplan-Meier analysis and log-rank test. A Cox regression model was performed for univariate and multivariate analysis.

RESULTS

209 patients were included with majority of adenocarcinoma (79.5%). First-line treatment was cytotoxic chemotherapy (50.2%), EGFR-targeted therapy (14.8%), chemoimmunotherapy (1.9%), and ALK-targeted therapy (1.4%). 31.6% received best supportive care. Median time of follow-up was 13 months, median overall survival was 11.2 months (95% CI, 7.9-14.4), 13 months for adenocarcinoma (95% CI, 8.1-17.9), and 2.5 months for squamous cell carcinoma (95% CI, 0.6-4.4) (P < .001). Median progression-free survival was 9.3 months (95% CI, 7.9-10.7) without differences according to the type of first-line therapy. Median time-to-treatment was 55 days and only 54% of patients with a tested actionable mutation in EGFR received an EGFR-targeted therapy as the first-line treatment. Multivariate analysis showed that squamous cell carcinoma histology and receiving best supportive care were independent factors for worse overall survival ((HR:1.8, 95% CI, 1.076-3.082, P=.026) and (HR:14.6, 95% CI, 8.921-24.049, P < .001), respectively). Meanwhile, squamous cell carcinoma histology was an independent factor for worse progression-free survival (HR:3.4, 95% CI, 1.540-7.464, P=.002).

CONCLUSIONS

Despite advances in precision medicine, during the study period, cytotoxic chemotherapy was the most used treatment in our patients. Furthermore, about a third of them received best supportive care. The use of targeted therapies has been restricted by access to molecular diagnosis and remained low until 2018. Access to immunotherapy should be prioritized.

A Two-Time Point Analysis of Gut Microbiota in the General Population of Buenos Aires and Its Variation Due to Preventive and Compulsory Social Isolation During the COVID-19 Pandemic

The COVID-19 pandemic poses a great challenge to global public health. The extraordinary daily use of household disinfectants and cleaning products, social distancing and the loss of everyday situations that allow contact between individuals, have a direct impact on the transfer of microorganisms within the population. Together, these changes, in addition to those that occur in eating habits, can affect the composition and diversity of the gut microbiota. A two-time point analysis of the fecal microbiota of 23 Metropolitan Buenos Aires (BA) inhabitants was carried out, to compare pre-pandemic data and its variation during preventive and compulsory social isolation (PCSI) in 2020. To this end, 23 healthy subjects, who were previously studied by our group in 2016, were recruited for a second time during the COVID-19 pandemic, and stool samples were collected from each subject at each time point (n = 46). The hypervariable region V3-V4 of the 16S rRNA gene was high-throughput sequenced. We found significant differences in the estimated number of observed features (p < 0.001), Shannon entropy index (p = 0.026) and in Faith phylogenetic diversity (p < 0.001) between pre-pandemic group (PPG) vs. pandemic group (PG), being significantly lower in the PG. Although no strong change was observed in the core microbiota between the groups in this study, a significant decrease was observed during PCSI in the phylum Verrucomicrobia, which contributes to intestinal health and glucose homeostasis. Microbial community structure (beta diversity) was also compared between PPG and PG. The differences observed in the microbiota structure by unweighted UniFrac PCoA could be explained by six differential abundant genera that were absent during PCSI. Furthermore, putative functional genes prediction using PICRUSt infers a smaller predicted prevalence of genes in the intestinal tryptophan, glycine-betaine, taurine, benzoate degradation, as well as in the synthesis of vitamin B12 during PCSI. This data supports the hypothesis that the microbiome of the inhabitants of BA changed in the context of isolation during PCSI. Therefore, these results could increase the knowledge necessary to propose strategic nutraceutical, functional food, probiotics or similar interventions that contribute to improving public health in the post-pandemic era.