Figure 5.

Outgrowths of transplanted parous and age-matched virgin tissue. Outgrowths of transplanted parous and age-matched virgin tissue contain basal/myoepithelial cells, luminal oestrogen receptor-negative (ER^-) cells and luminal oestrogen receptor-positive (ER⁺) cells. (a), (b) H & E-stained section of ductal-type transplant outgrowth. (c), (d) H & E-stained section of alveolar-type transplant outgrowth. (a), (c) Bar = 120 μm. (b), (d) Bar = 20 μm. (e) to (h) Sections of outgrowth stained by multiple immunofluorescence for cell-type specific markers. All nuclei are counterstained with DAPI (blue). Bar = 20 μm. (e) Ductal outgrowth stained for keratin 14 (red) and keratin 18 (green). (f) Ductal outgrowth stained for keratin 14 (red) and ER (green). Arrows, examples of ER⁺ luminal epithelial nuclei. (g) Alveolar outgrowth stained for keratin 14 (red) and keratin 18 (green). (h) Alveolar outgrowth stained for keratin 14 (red) and ER (green). Arrows indicate rare interstitial ER⁺ cells between alveolar structures.