The role of family history and risk of breast cancer aggressiveness in African American and European American women
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INTRODUCTION: European-American (EA) women, overall, have higher breast cancer incidence than African-American (AA) women. However, AA women are more likely to be diagnosed at a younger age and to have more aggressive tumors, characterized by higher grade, higher proliferative indices, and lack of expression of estrogen and progesterone receptors. AA women are also more likely than European-Americans to be negative for HER-2 amplification. These triple negative breast cancers are most lethal because they are not responsive to hormonal therapy or to herceptin, so fewer treatment options are available for this aggressive form of breast cancer. The reasons for these racial differences in breast cancer biology and age at onset are unknown. In fact, risk factors such as family history, the role of which is well studied in EA women remain unexplored in AA women. The objective of this study is to examine the increased risk of breast cancer (overall and by subtype) associated with having a family history (overall and by subtype) in both AA and EA women. MATERIALS AND METHODS: The proposed study builds upon an ongoing case-control study (Women's Circle of Health; PI Ambrosone), with biospecimens and extensive questionnaire data with large numbers of AA and EA women with breast cancer. Descriptive statistics were performed in order to best understand the counts, percentages, and proportions across race. Logistic regression was utilized to perform univariate and multivariate analyses in order to evaluate the association of known variables with the risk of subtypes. These analyses were performed for each race and then stratified for each race by menopausal status. RESULTS: The descriptive statistics showed that individuals with a family history of breast cancer (overall and by subtype) have a greater chance of being diagnosed with breast cancer (overall and by subtype) than the controls. Univariate and multivariate analyses showed that family history was significant in the AA and EA groups overall in breast cancer and ER- groups. Multivariate analysis showed family history was significant in the EA cohort. CONCLUSIONS: Family history plays a different role in breast cancer overall and by subtype. Family history was significant in breast cancer overall and by ER- subtypes for both AA and EA women. It was not significant in triple negative cases; however, the sample size was small so the next step would be to look at a larger cohort of triple negative cases.