Cancer stem cell subpopulations within the CD44high human breast cancer stem cell compartment

The CD44hi compartment in human breast cancer is enriched in tumor-initiating cells, however the functional heterogeneity within this subpopulation remains poorly defined. From a human breast cancer cell line with a known bi-lineage phenotype we have isolated and cloned two CD44hi populations that exhibited mesenchymal/Basal B and luminal/Basal A features, respectively. Rather than CD44+/CD24-,Basal B (G4) cells, only CD44hi/CD24lo, epithelioid Basal A (A4) cells retained a tumor-initiating capacity in NOG mice, form mammospheres and exhibit resistance to standard chemotherapy. Microarray data obtained from Affymetrix Human Gene 1.0 ST Array Five replicates of A4 and 5 replicates of G4