Fig. 2

Breast tissue components associated with percent mammographic density (PMD). PMD was assessed in the BioVision (Faxitron Bioptics) image of the enucleated breast from which the section had been taken (a) [Li T, et al. Cancer Epidemiol Biomarkers Prev. 2005;14(2):343–9]. We used quantitative microscopy in randomly selected areas of the tissue section (b) to measure the total, epithelial, and nonepithelial nuclear areas (H&E stain in c) as an index of the number of cells (outlined in green in d), the area of collagen (H&E stain in f and Masson’s trichrome in g), and the glandular area. PMD was associated inversely with age, and, after age adjustment, positively with the nuclear area (e) of epithelial and nonepithelial cells, glandular area, and the area of collagen (h). Box plots in e and h show the associations of total nuclear area (e) and collagen (h) with PMD. The median values are shown as horizontal lines, and the boxes show the 25th and 75th percentiles of the distributions. Age, parity, and menopausal status were also associated with variations in one or more of these tissue components. Similar associations of PMD with these breast tissue components have been found in prophylactic mastectomies [13]. Original magnification ×10 (c, d, f, and g)