Abstract P5-03-17: BRCA1/2 gene mutations in patients with high-risk breast cancer in a tertiary-level hospital in Guatemala

Abstract

Objectives, to stablish the frequency of BRCA1/2 mutation rate in high-penetrance breast cancer susceptibility population Methods Based on NCCN guidelines for testing criteria for high-penetrance breast cancer susceptibility genes genetic counseling was offered to 140 breast cancer patients in the hemato-oncology unit of Roosevelt Hospital at Guatemala City performing test with NGS and MLPA technology from 2019 to 2021. Results The overall BRCA1/2 mutation rate high-risk patients were 23% (33/140). Of the patients with mutations, 66.6% (22/33) had BRCA1 mutation, 33.3% (11/33) had BRCA2 mutation, of the mutated population the median age was 45 years. Regarding the phenotype in the mutated population, 75% were triple negative, 16% luminal and 9% with Her2 overexpression. Of the patients carrying the BRCA1 mutation, we identified the c.212+1G>A mutation in 40% of the patients, possibly a founder mutation. In the triple negative population and under 45 years of age, the percentage of patients with BRCA 1/2 mutation is 40.9 (88.8% BRCA1 and 11.1% BRCA2). Conclusions: we found a percentage of BRCA 1/2 mutations in the selected population (NCCN criteria) similar to that reported in other Latin American countries, highlighting the high percentage of BRCA mutations in women under 45 years with triple negative phenotype, previous reports have highlighted the frequency of the c.212+1G>A mutation of BRCA1 in breats cancer patient in Guatemala, in this study 40% of the BRCA1 mutations correspond to said mutation, considering it as a probable founder mutation. Citation Format: Juan Alvarado-Muñoz, Agatha Reyes-Morales, Marco Chivalan, Silvana Torselli, Hector Valenzuela, Gozalo Yalibat, Mario Ordoñez, Rosa León, Egly Alvarez. BRCA1/2 gene mutations in patients with high-risk breast cancer in a tertiary-level hospital in Guatemala [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-03-17.