Correlations of Cancer Stem Cell-Related Markers CD44+/CD24-/low and ALDH1 Expression in Breast Cancer and Its Significance

In this study, we tried to explore the characteristics of cancer stem cell-related markers CD44 and CD24 expression in breast cancer, and to investigate the relationship between CD44(+)/CD24(-/low) cells, ALDH1 and the expression of HER-2, ER, PR, CK5/6, and its correlation with clinical pathological factors. The single and double streptavidin-biotin-peroxidase immunohistochemistry of CD44 and CD24 were performed on 10 cases of breast lobular hyperplasia, 10 cases of simple ductal hyperplasia, 42 cases of ductal carcinoma in situ and 463 cases of breast invasive ductal carcinoma. And Immunohistochemistry of ALDH1, HER-2, ER, PR, CK5/6 was used on 463 cases of invasive ductal carcinoma, which the expression of the conditions as immunophenotyping. Results showed that CD44 positive cells located in the membrane. The positive rate was statistically different between the invasive carcinoma and the ductal carcinoma in situ. The expression of CD24 was found in luminal border of a tubule of non-cancerous breast tissues, but it was expressed both lumincal border and cytomembrane of cancerous tissues. The positive rate of CD24 in invasive carcinoma was higher than that in ductal carcinoma in situ. The CD44+/CD24(-/low) phenotype is enriched in basal-like breast tumors. CD44(+)/CD24(-/low) cells have a high expression rate of breast carcinoma in situ and poorly differentiated cancer than invasive cancer and well differentiated cancer. The change of CD24 expression from the luminal border in non-cancerous tissues to the cytomembrane in cancerous tissues suggested CD24 may involve in carcinogenesis of breast cancer.