Abstract PS3-03-12: From Pathogenic Variant to Action: Genetic Risk Identification and Preventive Oncology in Brazil’s Public Health System

Abstract Approximately 10% of breast and ovarian cancer cases are hereditary. Identifying germline pathogenic variants and acting on this information through preventive strategies is a key pillar of precision oncology. In Brazil, the public health system (SUS) in Goiás has incorporated genetic risk screening and management, setting a precedent for accessible, population-level genomic medicine.This study aimed to evaluate the frequency of germline pathogenic variants in patients at risk for hereditary breast and ovarian cancer, and to track these variants among their relatives for early diagnosis and prevention. We evaluated 268 patients who met the 2025 National Comprehensive Cancer Network (NCCN) criteria for hereditary breast and ovarian cancer syndromes, alongside 268 parents. All participants were referred to the Human Genetics Center at UFG through the SUS network.Following pre-test counseling and informed consent, blood samples were collected and analyzed using next-generation sequencing (NGS) with the Oncomine™ BRCA Expanded Panel (Ion Torrent platform). Among the 268 index patients, 14% (38/268) had pathogenic germline variants. The distribution was: BRCA1 (50%, 19/38), TP53 (21%, 8/38), PALB2 (10.5%, 4/38), CHEK2 (2.9%), BRCA2 (5.3%), and ATM (5.3%).Further familial testing was conducted in 30 families. Among eight families with the TP53 c.1010G>A variant, 36 of 99 tested relatives (36.4%) were positive. In two BRCA2-positive families, 9 of 18 relatives (50%) carried the same variant. Altogether, 45 of 117 relatives (38.46%) tested positive for the familial variant.Crucially, all relatives with positive results were evaluated by a medical geneticist and referred for cancer surveillance and risk-reducing strategies according to NCCN 2025 guidelines. This included MRI, mammography, and risk-reducing surgery when indicated, ensuring translation from genetic finding to clinical action.The project established a structured, replicable workflow for managing hereditary cancer risk in families. This includes genetic counseling, testing, cascade screening, and follow-up within the public healthcare system. By integrating genetic risk management into routine SUS care, the program enables early-stage diagnosis and reduces cancer-related mortality, particularly in underserved populations.This initiative demonstrates that comprehensive genomic care and precision prevention are feasible within a public system and scalable to other regions. It highlights how transforming a genetic finding into preventive action can generate real-world impact bridging the gap between variant and value. Citation Format: L. P. Lacerda, P. F. Silva, K. M. Veiga, B. F. Nascimento, I. M. Calassa, W. D. Oliveira, A. S. Limongi, R. L. Mesquita, K. J. Monteiro, R. R. Santos Junior, R. Taminato, R. M. Rahal, E. P. Silveira-Lacerda. From Pathogenic Variant to Action: Genetic Risk Identification and Preventive Oncology in Brazil’s Public Health System [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-03-12.