Abstract 1938: Germline mutations in breast cancer genes are associated with early age of diagnosis and triple negative disease in Guatemalan and US Hispanic women
Authors: Paredes Jesica Godinez , Rodriguez Isabel , Ren Megan , Orozco Anali , Ortiz Jeremy , Albanez Anaseidy , Jones Catherine , Nahleh Zeina , Barreda Lilian , Garland Lisa , Wu Dongjing , Wang Jiahui , Argueta Victor , Orozco Roberto , Gharzouzi Eduardo , Dean Michael 
Published: April 2023

Abstract Background: Mutations in hereditary breast cancer genes play an essential role in cancer risk. Little is known of the type and frequency of mutations in Hispanic populations in the United States and Central American countries, including Guatemala.

Methods: We used exome sequencing to identify mutations in blood DNA from unselected Hispanic breast cancer cases from community recruitment and from two hospitals each in Texas and Guatemala. Data from a structured questionnaire was used to compare mutation carriers of medium and high penetrance genes. Variants were annotated with ClinVar and VarSome.

Results: We recruited 262 Hispanic US women, 37 (14%) from community-based recruitment and 225 (86%) from hospitals in Texas. In addition, we ascertained 633 patients from two hospitals in Guatemala City. A total of 91 out of 895 subjects (10%) had a variant classified as pathogenic in a gene with known high or medium penetrance for inherited breast cancer. The most frequently mutated genes were the high penetrance BRCA1 (44/895, 4.9%) followed by BRCA2 (23/895, 2.6%), PALB2 (5/895, 0.6%), CHEK2 (5/895 0.6%), ATM (6/895, 0.7%) and TP53 (6/895, 0.7%). Pathogenic variants were also detected in the moderate penetrance genes BARD1 and MSH6, and rare pathogenic variants detected in the low penetrance genes AXIN2, FH, MLH1, MSH2, MUTYH, NF1, and SDHB. The high ratio of BRCA1/BRCA2 mutations is due to the presence of two potential founder mutations, BRCA1 c.212+1G&gt;A splice mutation (18 cases) and BRCA1 c.799delT (9 cases) in Guatemala. Compared to all others, cases with pathogenic mutations had a significantly earlier age at diagnosis (45 vs. 52 years, P&lt;0.001) and were more likely to have a diagnosis before menopause. A higher percentage of mutation carriers had a relative with any cancer (51% vs. 37%, P=0.038) or breast cancer (33% vs. 15%, P&lt;0.001). Patients with pathogenic mutations had a significantly higher percentage of triple-negative disease (60% vs. 13%, P=0.00046). Finally, mammography usage was less frequent in women with a lower socioeconomic status, indicating that this group is less likely to be screened for breast cancer (P&lt;0.001).

Conclusions: Guatemalan women have rates of hereditary breast cancer mutations like other populations, and these women are more likely to have early age at diagnosis, triple-negative disease, and

family history. Patient recruitment was higher using hospital-based versus community enrollment. This data supports genetic testing in breast cancer patients and those at high risk as part of a strategy to reduce breast cancer mortality in Hispanic women.

Citation Format: Jesica Godinez Paredes, Isabel Rodriguez, Megan Ren, Anali Orozco, Jeremy Ortiz, Anaseidy Albanez, Catherine Jones, Zeina Nahleh, Lilian Barreda, Lisa Garland, Dongjing Wu, Jiahui Wang, Victor Argueta, Roberto Orozco, Eduardo Gharzouzi, Michael Dean. Germline mutations in breast cancer genes are associated with early age of diagnosis and triple negative disease in Guatemalan and US Hispanic women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1938.