Researchers Discover a DNA Marker May Indicate Differences in Breast Cancer
Researchers and doctors at the North Shore-LIJ Health System and the Feinstein Institute for Medical Research have discovered a potential explanation for why breast cancer is not experienced the same way with African-American and Caucasian patients. Their data was presented at the 2012 American Society of Clinical Oncology (ASCO) annual meeting in Chicago.
Breast cancer is more common in Caucasian 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 Caucasian women. Because of this, African-American women have a lower breast cancer survival rate than Caucasian women. To explore the reasons why, researchers and doctors at the North Shore-LIJ Health System and the Feinstein Institute for Medical Research 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 Caucasian women, and 2) if variation in microRNAs may explain the observed survival difference between African-American and Caucasian women.
In this study, microRNA profiles from the blood of 32 female patients were collected before removal of breast tumors. The mean age of the patients was 50 years, ranging from age 31 to 68, and 10 of the patients had stage III triple-negative breast cancer (five were African American and five were Caucasian), 10 patients had stage III estrogen-receptor or progesterone-receptor positive breast cancer (five were African American and five were Caucasian), and 12 patients were controls (six were African American and six were Caucasian). Triple-negative breast cancer refers to any breast cancer that does not express three receptors known to advance most breast cancers; estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2 (HER2). Although triple-negative breast cancer is estrogen-receptor negative, progesterone-receptor negative and HER2 negative, and the most successful treatments for breast cancer target these receptors, triple-negative breast cancer typically responds to chemotherapy.