African-American/White differences in breast carcinoma: p53 alterations and other tumor characteristics

Despite mounting evidence that breast tumors in African-American (AA) women are more aggressive compared with breast tumors in white (W) women, little is known regarding racial/ethnic differences in genetic alterations that may be of prognostic importance.

In this population-based cohort of 322 AA women (45%) and W women (55%) who were diagnosed with breast carcinoma between 1987-1989, the authors evaluated available archived tumor tissue (n = 247 samples) for racial differences in selected genetic alterations and other prognostic indicators. Tumor characteristics were assessed by immunohistochemistry and/or expert review.

Alterations in p53 were significantly more common in AA women compared with W women (odds ratio, 4.00; 95% confidence interval, 1.77-9.01) and remained statistically significant in models that were adjusted for disease stage at diagnosis, according to American Joint Committee on Cancer (AJCC) criteria, and for other prognostic indicators. No racial difference with regard to HER-2/neu status was observed, but alterations in c-met were more common in AA women once the model was adjusted for negative confounders (not significant). Among other tumor characteristics, significant findings included later AJCC stage and higher histologic and nuclear grade tumors in AA women. In addition, the burden of aggressive tumor characteristics was greater in AA women because they were more likely to be at high risk on multiple factors (e.g., both high histologic grade and high nuclear grade [P = 0.03] and negative status for both estrogen receptors and progesterone receptors [P = 0.01]).

Data from this population-based cohort confirmed that breast tumors in AA women most likely are more aggressive compared with breast tumors in W women and offer new evidence for possible racial/ethnic differences with regard to p53 alterations.