According to the results of a study published in the Journal of the American Medical Association, premenopausal Black women are more likely than other women to develop an aggressive type of breast cancer known as basal-like.
Outcomes among women with breast cancer, including mortality rates, have varied widely and persistently between racial and ethnic groups. Overall, Black women have a significantly higher rate of cancer that is detected at an advanced stage and, more importantly, have a significantly higher breast cancer mortality rate than White women. The difference by race in breast cancer mortality is especially apparent among younger women: among women under the age of 50, Black women have a 77% higher breast cancer mortality rate than White women.
Now, thanks to the technique of gene expression profiling, scientists may have identified one piece to this puzzle. Gene expression profiling explores the patterns of genes that are active in tumor cells. Studies suggest that gene expression may provide information about prognosis or likely response to treatment in several types of cancer. This technique may allow for more accurate classification of cancer type than currently available methods.
Gene expression profiling has identified several subtypes of breast cancer. These subtypes appear to differ with respect to prognosis and responsiveness to particular treatments. Basal-like breast cancer refers to a type of breast cancer that has been linked with worse outcomes. In addition to other characteristics, basal-like tumors are estrogen receptor-negative, progesterone receptor-negative, and HER2-negative.
To explore how subtypes of breast cancer differ by age and race, researchers evaluated information from the Carolina Breast Cancer Study. This study was designed to assess environmental and molecular contributors to breast cancer risk.
- Among women with breast cancer, premenopausal Black women were more likely than other women to have basal-like tumors. Basal-like tumors were identified in 39% of premenopausal Black women, 14% of postmenopausal Black women, and 16% of pre- or post-menopausal White women.
- Another poor-prognosis subtype of breast cancer is estrogen receptor-negative and HER2-positive. The frequency of this type of breast cancer did not vary by race or menopausal status.
The researchers conclude that basal-like breast tumors were more common in premenopausal Black women than in postmenopausal Black women or pre- or post-menopausal White women. This may contribute to the higher breast cancer mortality rate in young Black women.
Reference: Carey LA, Perou CM, Livasy C et al. Race, Breast Cancer Subtypes, and Survival in the Carolina Breast Cancer Study. Journal of the American Medical Association . 2006;295:2492-2502.