Fig. 5

Metformin decreases aromatase-positive, tumor-associated macrophages. a Quantification of aromatase-positive cells and b CD68-positive (CD68⁺) macrophages costaining for aromatase in the tumor border of tissues from control or metformin-treated rats. c Representative control and metformin-treated IHC images of CD68 and aromatase dual staining in tissue bordering mammary tumors (T) (arrows: yellow = CD68⁺aromatase⁺, brown = CD68⁺; scale bar = 50um). d Aromatase expression by Western blotting (WES system) from in vitro activated M1 and M2 rat macrophages using two different primary antibodies (Ab #1: Novus NB100-1596; Ab #2: clone 677, Baylor College of Medicine). Controls include ovary (positive control) and ovary in which the primary antibody was preincubated with an aromatase blocking peptide for 1 h, as well as KGN cells with (positive control) and without (negative control) forskolin treatment. e IHC intensity score for ER and PR (0 = no stain; 1 = weak; 2 = moderate; 3 = strong staining). *p < 0.05