P53 as a Marker of Prognosis in African-American Women with Breast Cancer

Abstract

p53 overexpression has been identified as a poor prognostic marker in breast cancer. We investigate the value of p53 status within the context of stage and intrinsic subtype classification (subtype), in a group of African-American (AA) women of lower socioeconomic status (SES) with primary breast cancer. Participants were 331 consecutive AA women treated at an urban hospital (median follow-up 41 months) with known subtype [luminal A = estrogen receptor (ER)+ and/or progesterone receptor (PR)+, human epidermal growth factor receptor 2 (HER2)-; luminal B = ER+ and/or PR+, HER2+; HER2+ = ER-, PR-, HER2+; basal = ER-, PR-, HER2-, cytokeratin (CK)5/6+, and/or HER1+; and unclassified = negative for all five markers] and p53 (Pab1801 antibody) immunohistochemical status. Proportional hazards regression models were used to select and evaluate factors prognostic for all-cause mortality. p53+ status was associated with grade 3 tumors, ER/PR- status, and basal subtype. On univariate analysis, factors related to survival were stage, grade [(3/1) hazard ratio (HR) = 2.64; 95% confidence interval (CI), 1.15-6.07], subtype [(ex. basal/luminal A) HR = 2.15; 95% CI, 1.34-3.45], and p53 status [(+/-) HR = 1.77; 95% CI, 1.15-2.72]. Multivariable modeling indicated that p53+ status remained a negative prognostic factor (HR = 1.63; 95% CI, 1.01-2.59) after adjustment for effects of age, stage, grade, and subtype; 5-year adjusted survival was significantly greater for p53- (66.7%) than p53+ cases (54.7%). p53 status is an independent predictor of survival after consideration of other strong prognostic factors such as stage, tumor grade, and subtype, and thus may be useful in identifying AA women at high risk of breast cancer mortality.