Basal subtype predicts poorer prognosis in younger, but not older, African-American women with breast cancer.

2510 Introduction: Prior reports suggest that a higher prevalence of basal subtype (basal) tumors in younger African-American (AA) women with breast cancer, could contribute to their observed poorer prognosis. The aim of this study was to determine and compare the value of basal subtype as a prognostic marker in AA women Methods: Immunohistochemical surrogates for intrinsic subtype classification were applied to tumors from 280 consecutive AA women. Correlates were examined with logistic regression and were compared as odds ratios (OR) and 95% confidence intervals (CI), and survival was computed using the Kaplan-Meier method with log-rank test. Results: Overall subtype distribution was: luminal A (estrogen [ER+], &/or progesterone receptor [PR+], & human epidermal growth factor receptor-2 [HER2-]) = 58%; luminal B (ER+, &/or PR+, & HER2+) = 10%; basal (ER-, PR-, HER2-, cytokeratin 5/6+ &/or HER1+) = 20%; HER2+/ER- type (ER-, PR-, & HER2+) = 10%; and unclassified (negative for all 5 markers) = 1%. For 85 women Conclusions: This study demonstrates that basal-subtype predicts poorer prognosis in younger, but not older, AA women with breast cancer, and these findings have important treatment implications for both groups of women. This effect appears independent of stage and may partly explain survival disparity in younger AAs, and is consistent with prior reports.