Immunohistochemical staining was done using rabbit polyclonal antibodies raised against synthetic peptides that correspond to regions in the mature forms of TGF-β1, TGF-β2 and TGF-β3: anti-TGF-β1-LC and anti-TGF-β1-CC [19], anti-TGF-β2 (sc-90; Santa Cruz Biotechnologies Inc, Santa Cruz, CA, USA), and anti-50-60-β3-LC [20], respectively. Anti-latent TGF-β-binding protein (LTBP; Ab39) was raised against the purified full-length platelet LTBP [21]. The antibodies were affinity purified against the immunizing peptide (anti-TGF-β3) or against protein A sepharose (anti-TGF-β1-LC, anti-TGF-β1-CC and anti-TGF-β2). Immunohistochemical staining was performed using an indirect immunoperoxidase detection protocol (Vectastain Elite kit, Vector Laboratories, Burlingame, CA, USA). Staining intensity was scored on a scale of 0-4+, using the mouse embryo control section as a reference standard for each run. Ducts and periductal stroma were scored independently. Staining was scored in a blinded manner by two independent observers, and discrepancies were rescored by consensus. Staining intensity was plotted as the mean ± standard deviation for each experimental group.