CD44+/CD24‑ phenotype predicts a poor prognosis in triple‑negative breast cancer

Cancer stem cells are enriched in triple‑negative breast cancer (TNBC) tumor tissues, which present strong capacities of proliferation and tumorigenicity. The present study detected the distribution of cancer stem cell markers cluster of differentiation (CD)44/CD24 and analyzed the clinical outcomes of different CD44/CD24 phenotypes in patients with TNBC. Multivariate Cox regression analyses were performed with regard to the prognostic value of cancer stem cell markers CD44/CD24, aldehyde dehydrogenase 1 and other baseline clinical characteristics, including tumor size, lymph node involved, adjuvant chemotherapy, Ki‑67, breast cancer susceptibility gene 1, cellular tumor antigen p53, vimentin and basal‑like status. The multivariate analyses showed that three of these factors, CD44/CD24 phenotype, basal‑like status and number of lymph nodes involved, had an impact on overall survival. Furthermore, patients with CD44+/CD24‑ phenotype, basal‑like tumors and ≥4 lymph nodes involved had a significantly worse prognosis. The expression of CD44 and CD24 was detected by double‑staining immunohistochemistry, which can locate cancer stem cells individually. Overall, the present results indicated that CD44/CD24 status evaluated by double‑staining immunohistochemistry constitutes an independent prognostic factor for TNBC.