High fibrosis regions have greater acidic glycoprotein content. A. Representative images of patient-matched low and high fibrosis regions of human breast tumors stained with H&E, Trichrome, Picrosirius red (polarized image; inset brightfield), and Alcian Blue. Scale bar is 100 μm. B-D. Quantification of positively stained area of B. Trichrome, C. Picrosirius red, and D. Alcian blue in low and high fibrosis regions. E. Quantification of Alcian blue-positive area across whole tumor tissues by subtype. The mean is plotted and the error bars represent 1 standard deviation. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)