Abstract
African American (AA) women have a higher mortality from breast cancer (BC) compared to European American (EA) women. This may be due to the higher proportion of AA women with tumors that are diagnosed at more advanced stages and are characterized as being estrogen receptor negative (ER−)/progesterone receptor negative (PR−). Our study sought to determine whether self-reported race and percent African ancestry were associated with BC tumor characteristics. In a multi-center, population-based case–control study of BC, we determined percent African ancestry using ancestry informative markers (AIM) among women self-reporting race as AA or Black. BC tumor characteristics were associated with self-reported race (including a 30 % reduction in ER+/PR+ tumors [95 % confidence interval [CI]: 0.6–0.9] and a 1.5-fold increased risk of high grade [95 % CI: 1.2–1.9] for AA women compared to EA women). AIMs among AA women were not associated with BC tumor characteristics (AA women with ≥95 % versus <80 % African ancestry, odds ratio [OR] = 1.0 for ER+/PR+ [95 % CI: 0.6–1.8] and OR = 0.9 for high-grade tumors [95 % CI: 0.6–1.4]). Similar findings were observed for BC stage. While BC subtypes were associated with self-reported race, BC subtypes were not associated with percent African ancestry. These study results suggest that subtle differences in percent African ancestry are less important than the overall presence of African ancestry in relation to BC tumor characteristics.
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Acknowledgments
The authors would like to thank the study participants for their contribution to this research. The Women’s CARE study was supported by the National Institute of Child Health and Human Development, with additional support from the National Cancer Institute, through contracts with Emory University (N01 HD 3-3168), the Fred Hutchinson Cancer Research Center (N01 HD 2-3166), Karmanos Cancer Institute at Wayne State University (N01 HD 3-3174), the University of Pennsylvania (N01 HD-3-3176), and the University of Southern California (N01 HD 3-3175) and through an intra-agency agreement with the Centers for Disease Control and Prevention (Y01 HD 7022). The research generating the AIMs data was supported by the National Cancer Institute (R03 CA 123584). KWR was supported by the Cancer Epidemiology and Biostatistics Training Grant (2 T32 CA 09168) and NINR career development grant (K99 NR 012232). The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the National Institutes of Health and the Centers for Disease Control and Prevention.
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Reding, K.W., Carlson, C.S., Kahsai, O. et al. Examination of ancestral informative markers and self-reported race with tumor characteristics of breast cancer among black and white women. Breast Cancer Res Treat 134, 801–809 (2012). https://doi.org/10.1007/s10549-012-2099-0
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DOI: https://doi.org/10.1007/s10549-012-2099-0