CD44 and breast cancer: Because basal cells display the CD44+/CD24- or the CD44+/EpCAM- phenotype, and cells with these phenotypes often express higher levels of transcription factors involved in EMT13, 14, 27, it is possible that women of AA ancestry have differences in the following: the basal to luminal cell ratio; the rate of stem to luminal differentiation; the chromatin organization that permits quick transition between epithelial and mesenchymal states; and consequently a difference in susceptibility to breast cancer.