Fig. 4.

Effect of calcitriol and dietary vitamin D₃ on ERα, aromatase, and Ki67 protein expression in tumors in the premenopausal model. Vehicle [control (Con)], 0.05 μg calcitriol (Cal), and dietary vitamin D₃ (Vit D) were administered to intact female mice bearing BCa xenografts as described in Fig. 1. Tumors were harvested and fixed for IHC analysis of aromatase, ERα, and Ki67 expression as described in Materials and Methods. All tumors were immunostained with either anti-ERα antibody (A–C), an antiaromatase antibody (D–F), or an anti-Ki67 antibody (G–I) and are shown at ×400 magnification. No immunostaining was detected with IgG (negative control; not shown). ERα staining is indicated by the Allred score, given in parentheses below each panel. In the case of aromatase and Ki67, the numbers followed by the percent sign indicate percentage of cells showing positive staining.