Purpose: CD24 is expressed in hematological malignancies as well as in a large variety of solid tumors including breast cancer. We aimed to evaluate CD24 protein expression in breast cancer and to correlate to clinicopathological data including patient survival.
Experimental design: Primary breast carcinomas (201) with a mean clinical follow-up time of 53 months were immunostained using a monoclonal CD24 antibody (Ab-2, clone 24C02). The staining was evaluated as negative versus positive for statistical analysis.
Results: In invasive breast carcinomas, CD24 expression was observed in 84.6% of cases. In univariate survival analyses, a significant association of CD24 expression with shortened patient overall survival (5-year survival rate 91.9% versus 83.8%; P = 0.031; log rank test) and disease-free survival (5-year progression rate 88.3% versus 57.0%; P = 0.0008) was demonstrated. In multivariate analyses CD24, tumor grading and nodal status were significant prognostic parameters for shortened disease-free survival.
Conclusions: Our data suggest that CD24 expression in primary breast cancer as detected by immunohistochemistry might be a new marker for a more aggressive breast cancer biology.