Abstract P5-03-12: Prognostic role of stem cell markers in triple-negative breast cancer (TNBC)

Abstract

Abstract Introduction: Triple-negative breast cancer (TNBC) is among the most aggressive types of breast cancer with frequent recurrence and death despite chemotherapy. Studies have shown that cancer stem cells play a key role in many of the drug resistant cancers including TNBC. In this study, we report the expressions of four stem cell markers in 158 TNBC tumors. Design: Clinicopathological data were obtained from 158 triple negative breast cancers between 2002 and 2010. Tissue microarray was constructed and immunohistochemistry stains (IHC) for CD44 and CD24, CD 133 and ALDH1 were performed using the streptavidin-biotin method. Each set of TNBC consists of normal, ductal carcinoma in situ and invasive areas for assessment of IHC stains. Statistical analysis was done on the following parameters: Histological types, modified Bloom and Richardson grades, lymph-vascular invasion, lymph node status, tumor size, Ki67, presence of lymphocytic host response, age >50 or <50, BRCA status, prognosis (recurrence and death) and chemotherapeutic response. P values less than 0.05 were considered statistically significant. Results: the mean age of this cohort of TNBC patients was 55 with 64% white, 13.2% black, 12.6% Asian/Pacific, 3.8% Hispanic/Latino and 1.9% other. The majority of these tumors (82.3%) were grade 3, 15.2% were grade 2, and less than 1% was grade 1. CD24, CD44 and CD133 expressions were significantly higher in TNBC than in normal breast tissues (p = 5.53 e-10, p = 1.14 e-11, p = 2.25 e-08 respectively). While both CD24 and CD133 expressions predicted poor survival (p = 0.073 and p = 0.043 respectively), neither was associated with recurrence. In contrast to CD24, CD44 and CD133 expressions, ALDH-1 expression was rare in TNBC and surrounding normal tissues. When expressed, ALDH-1 was associated with poor survival but cases were too few to reach significance. None of the four stem cell markers studied were associated with any of the conventional histopathologic features and BRCA1 or BRCA2 mutations. Conclusions: Our study suggests that stem cell marker(s) may be prognostically important in TNBC patients. When it is fully characterized it may provide new insight in developing effective therapeutic strategies targeting stem cell related signaling pathways. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-03-12.