Researchers have discovered a potential explanation for why breast cancer is not experienced the same way with African American and white patients

Breast cancer is more common in white women than in African American women. However, African American women experience a more aggressive form of breast cancer that occurs almost a decade earlier than in white women. Because of this, African American women have a lower breast cancer survival rate than white women. To explore the reasons why, researchers conducted a study to determine 1) why the expression of a genetic marker embedded in deoxyribonucleic acid (DNA), called microRNA, differs between African American and white women, and 2) if variation in microRNAs may explain the observed survival difference between African American and white women. The study found that, 1) female white patients who had triple-negative breast cancer over-expressed 20 microRNAs (15 times higher than the controls), and none of the microRNAs these patients had were found in any of the African American patients, 2) female African American breast cancer patients overexpressed only six microRNAs (15 times higher than the controls), and none of these microRNAs were detected in white patients who had triple-negative breast cancer, and 3) four microRNAs in African American patients and eight microRNAs in white patients were not previously reported in association with breast cancer, which suggests that they may be connected to how the patient reacts to cancer. The striking difference in the patterns of microRNA expression between African American and white breast cancer patients may provide insight into answering why, when receiving similar treatments, outcomes are different between African Americans and whites. Breast cancer patients who have the most devastating outcome may carry the microRNAs that promote cancer. What the researchers saw in this study is that white women may carry microRNAs that protect against cancer while African American women do not express those microRNAs. The lack of expressing these microRNAs in African Americans could be the cause of the poor outcomes seen in these women.