Fig. 7

Cytokeratin (CK)-19, CK-14 and vimentin triple immunofluorescence staining. High mammographic density (HMD) (a) and low mammographic density (LMD) (b) tissue samples were stained with 4′,6-diamidino-2-phenylindole (a 1 and b 1), CK-14 (a 2 and b 2) CK-19 (a 3 and b 3) and vimentin (a 4 and b 4) and assessed as composite images (a 5 and b 5). Arrows indicate cells inside the epithelial layer that stained negative for CK-19 or CK-14, but positive for vimentin. (c) Using the point-counting method, the percentages of CK-14 basal epithelial cells and CK-19 luminal epithelial cells were determined, as were the number of vimentin-expressing CK⁻ cells per whole glandular area of the tissue sections. The results for HMD and LMD paired samples were analysed using the nonparametric Wilcoxon matched-pairs signed-rank test. VPCKN vimentin-positive, cytokeratin-negative. Scale bar = 10 μm