GATA3 downregulation is required for progestin-induced in vivo tumor growth. A) C4HD cells (106) from each experimental group were inoculated subcutaneously into female BALB/c mice treated or not with MPA (n = 6 for each experimental group), and tumor volume was calculated using the formula W2 x L/2, where W = width and L = length. The boxplot represents the values obtained for the area under the growth curve obtained for each experimental group (***P <0.001 and **P <0.01, one-way ANOVA). B) Protein extracts were prepared from tumor samples and immunoblotted for the indicated proteins. C) Immunohistochemistry for cyclin A2 in GFP, GFP-GATA3-WT and GFP-GATA3-S308A C4HD tumors. Human normal breast tissue was used as negative control (lower panel). Representative images of each experimental group are shown. Scale bar = 20 μm. ANOVA, analysis of variance; MPA, medroxyprogesterone acetate.