Abstract B48: Design of a feasibility study of breast cancer candidate genes in three ethnic groups.

The purpose of this presentation is to highlight the design and preliminary recruitment outcomes of a translational feasibility study to investigate the impacts of selected genetic single nucleotide polymorphisms (SNPs) on ethnic disparities in breast cancer subtypes, defined by ER, PR, and Her2 expression, associated with higher breast cancer mortality rates. The study will investigate the frequencies of five SNPs in the 19p13 locus of BRCA1 and two SNPs on chr 5p12 in three ethnic groups: African Americans with Sea Island ancestry (SI; all four grandparents were born in SI geographic regions), African Americans without known Sea Island ancestry (AA; 0 grandparents were born in SI geographic regions), and European Americans (EA). The SI population is an AA subpopulation indigenous to the coastal southeast that has the lowest rates of European genetic admixture of AA tested.(1,2) Comparing risk alleles across these three ethnic groups provides a novel paradigm to assess the extent to which SI ancestry and social processes such as acculturation may be linked to breast cancer subtypes associated with poor prognosis. A protocol has been developed to identify, contact and recruit women recently diagnosed with breast cancer within each ethnic group. Breast cancer cases are initially ascertained through the South Carolina Central Cancer Registry (SCCCR). Recruitment methods encompass steps taken at the SCCCR that include passive consent from the physician of record to contact identified patients, followed by active consent from the identified patients prior to contact by study staff. An investigator-developed algorithm developed to determine SI ancestry of patients, based on geographic ancestry, is administered and eligible participants are asked to complete a telephone-administered survey and to provide a saliva sample for genetic analysis. Recruitment began in June 2012. To date, 23 participants have been recruited, of whom 6 are AA (26%) and 17 are EA (74%), with a mean age of 57.5 years (range =39-77 years). Recruitment will continue until 30 women in each ethnic group are enrolled (total 90 participants). The recruitment process is monitored using a CONSORT diagram. This work will ultimately identify loci for further investigation of breast cancer disparities in other groups and for future development of targeted clinical therapies. References: 1. Divers, J, Sale MM, Lu L, et al. The genetic architecture of lipoprotein subclasses in Gullah-speaking African American families enriched for Type 2 diabetes: the Sea Islands Genetic African American Registry (Project SuGAR). Journal of Lipid Research 2009;51:586-597. PubMed PMID: 9783527; PubMed Central PMCID: PMC2817588. 2. McLean DC, Jr., Spruill I, Argyropoulos G, et al. Mitochondrial DNA (mtDNA haplotypes reveal maternal population genetic affinities of Sea Island Gullah-speaking African Americans. American Journal of Physical Anthropology 2005;127:427-438. Citation Format: Marvella E. Ford, Joan E. Cunningham, Erika T. Brown, Ida J. Spruill, Anthony J. Alberg, Debbie C. Bryant, Karen D. Charles, Nestor F. Esnaola, Melanie S. Jefferson, Keith Whitfield, Rita M. Kramer, Susan Bolick, Deborah Hurley, Catishia Mosley, Tonya R. Hazelton, Vivian J. Bea, Dana R. Burshell, Shweta Singh, Emily Kistner-Griffin. Design of a feasibility study of breast cancer candidate genes in three ethnic groups. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B48.