Fig. 1: Breast cancer cells exhibit reduced ER-α expression in high stromal regions.

Tumors were stained for ER-α (A) and compartmentalized into defined areas of high (B; red border), medium (C; blue border) or low (D; green border) stromal infiltration, as demonstrated for a full tumor in (E). The DAB staining intensity was measured for each cell; the mean for all measured areas is shown in (F), and for each individual tumor compartmentalized according to stromal intensity in (G). Unpaired two-tailed t-test ****P < 0.0001. Error bars: SEM, data from n = 7 tumors. Cell enrichment scores for stroma or CAFs from different bioinformatic tools enable correlation of CAF content with ESR1 expression (H).