Fn structure differs around normal versus malignant prostate epithelium. (A–C) A minimal staining for Fn (brown) is observed around healthy (normal) prostate epithelium adjacent to cancer. Cells were counterstained with hematoxylin (blue). (D–I) Fn forms long parallel fascicles in invasive regions of two different cancer cases (D–F and G–I). E is an enlargement of D, and F is an enlargement of E. Similarly, H is an enlargement of G, and I is and enlargement of H. (D–I) Arrows indicate invading tumor cells. (J–L) Immunofluorescent labeling of αSMA (green; left), Fn (red; middle), and nuclear counterstain with DAPI (blue; right) indicate that myofibroblasts surround both benign (J) and malignant prostate (K and L) epithelium but only form long, parallel Fn fascicles around invading cells. Bars: (J–L, αSMA, Fibronectin, DAPI, and Overlay) 50 µm; (J–L, Zoom) 25 µm.