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Surveys find that African-American women are three times more likely to develop aggressive-type breast cancers and significantly more likely to die from breast cancer than women of other ethnicities. Some researchers have suggested that this may be due to poor access to mammography and less frequent breast cancer screenings among many African-American women. However, recent research has focused on differences in the characteristics of breast cancer among African Americans and women of other ethnicities. In a newly published study, researchers suggest that certain receptors on breast cancer cells, called isoforms, are present in substantially lower amounts in African-American women with breast cancer. The findings could help develop new treatments that target the unusual characteristics of breast cancer in African-American women. In recent years, researchers have found that African-American women tend to develop breast cancers with high histologic grades, poorer differentiation, and a higher S-phase than other women. All of these factors signal more aggressive breast cancers that are generally more difficult to treat. In an attempt to understand the differences in breast cancer between African Americans and women of other ethnicities, Indra Poola, PhD, a molecular biologist at Howard University, and her colleagues studied breast cancer tumor samples from 24 African-American women. In particular, the researchers examined certain characteristics of the cancer cells’ estrogen receptors. All normal breast cells contain estrogen receptors on the surfaces of their cells. Approximately 80% of breast cancers also contain estrogen receptors. Because cancers with estrogen receptors depend on estrogen to grow, they cannot survive when specific breast cancer treatments, such as the drug tamoxifen, block estrogen from them. In the study, Dr. Poola and her colleagues studied four types of estrogen receptors called isoforms. Isoforms are known to play a key role in regulating the amount of estrogen that reaches breast cells. Among the 24 African-American breast cancer samples, the researchers found that the quantity of one of the isoforms (called beta-estrogen receptor) was substantially lower compared with normal African-American breast cell samples. This beta-estrogen receptor is thought to have a protective effect against cancer, and its absence in the African-American breast cancer tumor samples may explain why African-American women tend to have more aggressive breast cancers. While Dr. Poola and her colleagues did not examine breast cancer tumor samples from Caucasian women or women of other ethnicities, they believe that, based on their unpublished research, estrogen receptors differ among African-American women. According to Dr. Poola, these study results could help researchers develop breast cancer treatments that focus on isoforms. The study also reinforces the need to treat many African-American patients with the drug tamoxifen, which blocks estrogen from reaching estrogen receptors in breast cancer cells. Since no woman can control what type of breast cancer she develops, experts recommend that all women follow the established guidelines for early breast cancer detection. In general, the earlier breast cancer is detected, the more likely it can be successfully treated in women of all races and ethnicities. Guidelines for early breast cancer detection:
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