Extended Data Fig. 3: High-risk mammary epithelial progenitors with various mutations show basal differentiation biases after 7 days of culture.

(a-d) Histograms of cKit-enriched cells stained with KRT14 and KRT19 that were fixed after 2 days of culture from (a) AR women with no predisposing mutations and (b) HR women, and after 7 days of culture from (c) AR women and (d) HR women. (e-f) Immunofluorescent images of cKit-enriched cells stained for KRT19 (green) and KRT14 (red) that were fixed after 7 days of culture from (e) an AR woman (40 y) and (f) an HR woman harboring a germline BRCA2 mutation (44 y). (g-l) Density contour plots of KRT14 and KRT19 mean fluorescent intensity signals in cKit-enriched cells that were fixed after 7 days of culture from (g) AR younger women, (h) AR older women, and HR women harboring germline mutations of (i) BRCA1, (j) BRCA2, (k) PALB2 and (l) PALB2 (VUS)+APC (VUS). Scale bars = 50 μm. Abbreviations are as follows: VUS, variant of unknown significance. Experiments in e-f were repeated three times independently with similar results. The number of cell strains used in each experiment representing the two groups are as follows: e, five; f, thirteen.