[Pilot study on the correlation between high incidence of CD44+/CD24 -/low/ABCG2- cells and poor prognosis in breast cancer].

ABSTRACT

OBJECTIVE: To explore whether the CD44+/CD24(-/low)/ABCG2(-) (ATP binding cassette superfamily G member 2) cells are associated with prognosis and clinical response in breast cancer patients. METHODS: We investigated the paraffin-embedded tissues of 43 breast cancer patients with (23 cases) and without (20 cases) recurrences. Double-staining immunohistochemistry (IHC) was applied for the detection of CD44+/CD24(-/low) cells and single-staining IHC for ABCG2. Flow cytometry was used to analyze the CD45(-)/CD44+/CD24(-/low)/ABCG2(-) cells in 4 mL peripheral blood of patients with metastasis breast cancer and 11 healthy female volunteers as controls. RESULTS: The positive rate of ABCG2 in recurrence-group was higher but with no difference compared with controls (78.3 % vs 60.0%, P = 0.32). Double-staining IHC revealed that the percentage of CD44(+)/CD24(-/low) cells was higher in recurrence-group than non-recurrence group(65.2% vs 35.0%, P = 0.048)and higher percentage of CD44+/CD24(-/low) cells was significant associated with poor overall survival(P = 0.031). Patients with higher percentage of CD44+/CD24(-/low) cells have shorter disease free survival (DFS), but have no statistical significance. Flow cytometry revealed that the CD45(-)/CD44+/CD24(- /low)/ABCG2(-) cells were higher in breast cancer patients than those of the volunteers (median 679/10(5) cells vs 12/10(5) cells). The cell number of this subset was affected by chemotherapy but was not statistically consistent with clinical response. CONCLUSION: Our study suggests that CD44+/CD24(-/low) breast cancer stem cells in tumor tissue may be associated with poor prognosis. The incidence of CD44+/CD24(-/low)/ABCG2(-) cells in peripheral blood is more frequent in breast cancer patients but further investigation should be made to explore the relationship of this subset and disease prognosis.