Figure 2

MaSCs have a distinct gene expression profile. (A) Unsupervised hierarchical clustering heatmap of genes differentially expressed between MaSC, MYO, total basal, luminal ER- (ER-) and luminal ER+ (ER+) mammary epithelial subpopulations. Expression values represent median-centred value for each probeset. (B) Unsupervised hierarchical clustering of microarray expression data of the 69 top MaSC signature genes (Table 2) across the MaSC, MYO, total basal, ER- and ER+ populations. (C) qrtPCR validation of MaSC genes of interest identified by whole transcriptome microarray analysis. Expression of Cdh5, Gfra2, Krt15, Lgals1, Lgr5, Nfatc1, Pdgfb Prox1, Ptprb, Ptprz1, Tnc, Vim, Zeb1, Zeb2 in luminal ER-, luminal ER+, MYO and MaSC unamplified RNA determined by qrtPCR analysis. Data expressed as mean relative fold expression (±95% confidence intervals) over comparator population (luminal ER- cells) in three independent isolates of each cell population. Statistical significance was determined according to [74]. ^** P <0.01; ^* P <0.05; N.S not significant, relative to the next highest expressing population indicated by brackets. ER, estrogen receptor; MaSC, mammary stem cell; MYO, myoepithelial cell; qrtPCR, quantitative real-time rtPCR.