Stromal CD10 expression in breast cancer correlates with tumor invasion and cancer stem cell phenotype

Background: Previous investigations have indicated that CD10 is associated with biological aggressivity in human cancers, but the use of this marker for diagnosis and prognosis is more complex. The aim of this study was to evaluate the expression of CD10 in breast cancer and its association with the clinicopathological features. In addition, we investigated whether a relationship exists between CD10 expression and cancer stem cells. Methods: CD10 expression was examined by the immunohistochemistry in a series of 133 invasive breast carcinoma cases. Results were correlated to several clinicopathological parameters. Cancer stem cell phenotype was assessed by the immunohistochemical analysis of CD44 and ALDH1. Results: Significant CD10 expression was found in the fusiform stromal cells in 19.5% of the cases and in the neoplastic cells in 7% of the cases. The stromal CD10 positivity was more frequently found in tumors with lymph node metastasis (p = 0.01) and a high histological grade (p = 0.01). However, CD10 expression by the neoplastic cells correlates with a high histological grade (p = 0.03) and the absence of estrogen (p = 0.002) as well as progesterone (p = 0.001) receptor expression. We also found that CD10 expression by the stromal cells, but not by the neoplastic cells, correlates significantly with the expression of cancer stem cell markers (CD44+/ALDH1+) (p = 0.002). Conclusion: These findings support the role of the stromal CD10 expression in breast cancer progression and dissemination, and suggest a relationship with cancer stem cells.