Abstract 2784: Genetic analysis of breast cancer in admixed populations of central Colombia
Authors: Lott Paul C. , Criollo Angel , Tuazon Anna Marie , Alfonso Carolina Ramirez , Sahasrabudhe Ruta , Estrada Ana , Garcia Elisha , Prieto Rodrigo , Williamson John , Torres Javier , Bohorquez Mabel , Echeverry de Polanco Maria Magdalena ,   CHIBCHA Consortium, COLUBMUS Consortium, Carvajal-Carmona Luis G. 
Published: August 2015

Breast cancer (BC) is the most frequently diagnosed cancer among women with an estimated 1,676,633 new cases resulting in ∼521,817 deaths each year globally. Thus, it is no surprise BC research has become one of the hottest cancer research areas in the past three decades. Past studies examining and identifying BC risk loci have focused on three major populations (European, African, and Asian). Past research has led to greater understanding of the etiology (genetic and environmental) and treatment of BC; resulting in a ∼30% decrease in mortality rate in wealthy countries. However, when looking at BC incidence and mortality in low to middle income nations similar gains are not seen; in fact, in these countries mortality has increased in the past 20 years. This trend holds true for the Hispanic community. While Hispanic women have a ∼27% lower rate of BC than in non-Hispanic white women, Hispanic women are more likely to be diagnosed with larger tumors and later stage cancer, leading to ∼20% increase in mortality for Hispanic women compared to their non-Hispanic white counterpart with similar diagnosis stage and age. Differences in incidence and mortality have been attributed to environmental and genetic factors. This case-control association study aims to address a research disparity by examining the role of ethnicity and genetics on development of BC risk in central Colombian Hispanic populations. It provides one of the first assessments of known BC risk factors in the South American Hispanic community. The study was conducted in central Colombia using ∼600 breast cancer cases from COLUMBUS initiative & ∼700 matched cancer-free controls from the CHIBCHA consortium. Cases were genotyped using Affymetrix Axiom UK Biobank arrays and controls were genotyped using both Affymetrix Axiom LAT and Axiom Custom arrays followed by imputation using 1000 Genomes data. We analyzed previously discovered BC loci and under independent analysis found 6 significant loci: rs11780156 (P = 0.005, OR: 1.34), rs2981582 (P = 0.007, OR: 1.25), rs4784227 (P = 0.016, OR: 1.22), rs2981579 (P = 0.017, OR 1.21), rs1011970 (P = 0.0274, OR 1.20), rs1219648 (P = 0.042, OR 1.18) and several loci showing borderline significant associations involving the same risk allele. Interestingly, we identified additional novel BC risk loci that were genome-wide significant and are undergoing replication in populations from Central Mexico. In summary, we performed an assessment of BC risk loci in central Colombian Hispanic population and found significant overlap with BC risk loci previously identified in European and East Asian populations as well as potentially novel loci that are unique to Hispanic populations. These results are integral to the establishment of personalized medicine programs and will form the basis for future BC prevention and treatment program in Latin American and US Hispanics.

Citation Format: Paul C. Lott, Angel Criollo, Anna Marie Tuazon, Carolina Ramirez Alfonso, Ruta Sahasrabudhe, Ana Estrada, Elisha Garcia, Rodrigo Prieto, John Williamson, Javier Torres, Mabel Bohorquez, Maria Magdalena Echeverry de Polanco, CHIBCHA Consortium, COLUBMUS Consortium, Luis G. Carvajal-Carmona. Genetic analysis of breast cancer in admixed populations of central Colombia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2784. doi:10.1158/1538-7445.AM2015-2784