Abstract PO2-20-05: Onco-Genome Brazil: Mapping Breast and Prostate Cancer in the Brazilian Public Health System

Abstract

Abstract Background: Breast and prostate cancers are the most common malignancies diagnosed in women and men respectively, and present with great clinical heterogeneity, even in tumors with the same phenotypic characteristics. Somatic and germline molecular alterations in DNA may have prognostic and predictive impact, influencing response to therapies and overall survival. In addition, the evaluation of germline mutations can help identify individuals and families at higher risk for developing cancer. Aims: Our aim is to characterize the somatic and germline genomic landscape of women with locally advanced HER2-positive breast cancer and men with metastatic prostate cancer from Brazil. Secondarily, we aim to identify genetic variants associated with tumor prognosis and treatment response, identify patients carrying pathogenic alterations in cancer-predisposing genes, and characterize the genetic ancestry of the population included in the study. Trial design: This observational multicenter cohort study (NCT05306600) will include 550 adult patients from the five macro-regions of Brazil, divided into two arms: 1) breast cancer and 2) prostate cancer. Clinical and pathological data will be collected, as well as DNA samples from peripheral blood and tumor tissue. Whole-exome sequencing (WES) will be performed to identify variants that may be drivers and/or actionable in a specific patient or tumor. These variants will be interpreted and classified according to their population frequencies, in silico predictors, functional studies, and literature data, following international guidelines proposed by expert societies. This trial is supported by the Ministry of Health in Brazil and includes patients of the Public Health System. Eligibility criteria: In arm 1, the inclusion criteria are patients with a histological diagnosis of breast carcinoma with overexpression of HER-2, clinical stage II or III, and undergoing neoadjuvant treatment with chemotherapy plus trastuzumab. In arm 2, the criteria are patient with histological diagnosis of prostate adenocarcinoma, currently in clinical stage IV. Patients without availability of biological material collection are excluded from the study, as well as patients in whom there was no central confirmation of required histology. Statistical methods: Univariate and multivariate analyses will be conducted to evaluate the possible effect of specific genes or mutations on the investigated outcomes, including tumor prognosis and treatment response. Discussion: Currently, 265 participants have already been included in the study, 150 in arm 1 and 115 in arm 2. This trial will contribute to the construction of a robust database that should provide a better understanding of the genomic profile of patients with breast and prostate cancer in Brazil. For more information about the trial, please contact Daniela Rosa (daniela.rosa@hmv.org.br). Citation Format: Jaqueline Schuch, Cláudia Bordignon, Mahira Rosa, Angélica de Baumont, Marina Bessel, Gabriel Macedo, Daniela Rosa. Onco-Genome Brazil: Mapping Breast and Prostate Cancer in the Brazilian Public Health System [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-20-05.