Gene May Explain Poorer Breast Cancer Outcome Among African-Americans (dateline September 8, 2003)
Researchers have identified a gene that may help explain why African-American women do not respond as well to breast cancer treatment as white women. 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 poorer access to mammography and less frequent breast cancer screenings among many African-American women. However, a recent study shows that a gene called BP1, present more often in African-Americans, may cause breast cancer cells to resist treatments.
In recent years, researchers have found that African-American women tend to develop breast cancers with certain factors (such as high histologic grades, poorer differentiation, and a higher S-phase) that tend to make them more difficult to treat.
Recently, some research has shown that African-American women may be more likely than white women to develop non-estrogen sensitive breast cancers. That is, the cancer cells do not depend on estrogen for survival. Thus, hormonal treatments such as the drug tamoxifen, designed to "starve" the cancer cells of estrogen, are ineffective.
Now, researchers have found that a gene called BP1 tends to be more active in women with non-estrogen sensitive breast cancers. Dr. Sidney Fu of George Washington University and colleagues chose to study BP1 because their previous research showed that the gene was active in leukemia patients and caused cancer cells to resist treatment.
In the current study, Dr. Fus team analyzed breast cancer tissue samples of 46 patients. They found that while BP1 was active in 89% of the tumors of African-American women, it was active in only 57% of tumors of white women. Furthermore, all of the cancers in which BP1 was active were non-estrogen sensitive (i.e., they did not respond to hormonal treatments).
Though the small size of the study requires that the results be confirmed in a larger number of patients, Dr. Fu and colleagues suggest that BP1 may be an important factor that could help explain why breast cancers tend to be more aggressive and harder to treat in African-American women, compared to white women. However, the researchers will have to sort out other questions too, such as why BP1 was found in two non-cancerous breast tissue samples as well as in cancer samples.
Nevertheless, the study re-confirms the importance of early breast cancer detection. Finding breast cancer in its earliest stages improves the chances of successful treatment and survival. This is particularly important for African-American women, who tend to be diagnosed with later stages of the disease.
Guidelines for early breast cancer detection: