SMAD3 and infectious otitis media: Tumors from ApcMin/+ (Figure 2b, bottom left panel) and AOM (not shown) mice exhibited strong nuclear β-catenin immunoreactivity and reduced membrane staining (see inset), whereas tumors from Smad3-/- (Figure 2b, bottom right panel) and Tgfb1-/-; Rag2-/- (not shown) mice showed strong plasma membrane β-catenin staining with no nuclear accumulation (see inset).