Breast cancer stem cell markers CD44, CD24 and ALDH1: expression distribution within intrinsic molecular subtype

Background and AimThe study of CD44/CD24 and ALDH1 expression is the most accurate method to identify cancer stem cells (CSC) from breast cancer populations. However, the overlap between CD44+CD24−/low and ALDH1high CSC phenotypes in breast cancer seems to be very small, as well as their distribution among intrinsic breast cancer subtypes. Due to this discrepancy, it is imperative to improve the understanding of breast CSC marker distribution.Methods466 invasive breast carcinomas and eight breast cancer cell lines were analysed for the expression of CD44, CD24 and ALDH1, to evaluate their distribution among the distinct molecular subtypes.ResultsBasal-like tumours (76.5%) contained the higher percentage of cells with the CSC phenotype CD44+CD24−/low (p