Genetic Ancestry of 1127 Brazilian Breast Cancer Patients and Its Correlation With Molecular Subtype and Geographic Region

Author(s)

Vieira, Rene Aloisio da Costa ; Sant'Anna, Debora ; Laus, Ana Carolina ; Bacchi, Carlos Eduardo ; Silva, Rene Julias Costa ; de Oliveira-Junior, Idam ; Silva, Vinicius Duval da ; Pereira, Rui ; Reis, Rui Manuel

• Document type: Journal article
• Source: CLINICAL BREAST CANCER; v. 23, n. 5, p. 11-pg., 2023-07-01.

Abstract

No study evaluated genetic ancestry in breast cancer patients in Brazil. Ancestry was associated with nativity, ethnicity, clinical characteristics and molecular subtype. European ancestry was more frequent in Luminal Her negative and African ancestry was more frequent in triple negative. These facts may contribute better knowledge of breast cancer disparities and for planning public health strategies.Purpose: Breast cancer molecular subtypes show significant differences in different ethnic groups in the United States, but no study has evaluated genetic ancestry in breast cancer in Brazilian women. Methods: Breast cancer patients from distinct parts of Brazil were evaluated. Molecular subtypes were determined by immunohistochemistry. Genetic ancestry was evaluated using a panel of 46 AIMs (ancestry informative markers), which classified genetic ancestry as European, African, Asian, and Amerindian. PCR products were subjected to capillary electrophoresis and analyzed using GeneMapper 4.0 software. Ancestry was evaluated with Structure v.2.3.3 software. Ancestry was tested for corre-lations with geographic region and molecular subtype. The chi-square test and ANOVA with Bonferroni adjustment were applied. Results: Genetic ancestry and clinical data were evaluated in 1127 patients. Higher rates of self-reported white ethnicity, European ancestry, and HER-2- luminal tumors were identified in the South region, which may influence age at diagnosis and result in a higher rate of early tumors. Conversely, higher rates of African ancestry in the North and Northeast regions, self-reported nonwhite ethnicity, HER-2+ tumors, and triple-negative tumors were noted. Triple-negative and HER-2+ tumors were associated with higher advanced and metastatic disease rates at diagnosis, with triple-negative tumors being more frequent in young women. Conclusion: Differences in genetic ancestry, self-reported ethnicity, and molecular subtype were found between Brazilian demographic regions. Knowledge of these features may contribute to a better understanding of age at diagnosis and the molecular distribution of breast cancer in Brazil. (AU)

• FAPESP's process: 18/16629-9 - Characterization of ancestry in patients with breast cancer in Brazil and its correlation with the molecular subtype and geographical origin
• Grantee: Débora Sant' Anna de Andrade e Silva
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training