Immunohistochemical staining of EphB4 in several foci of a single prostate cancer sample. The expression of EphB4 a different foci in a single patient sample was compared by immunohistochemistry. Images from 10× magnification (A) and a region from this (as indicated by the box) at 20× magnification (B) are shown for 2 regions of normal prostate duct (1 and 2) and 8 regions with disease (3–10) from this single sample. A comparable level of EphB4 staining was seen in regions of high grade PIN (eg. focus 8 indicated PIN) and regions of poorly differentiated adenocarcinoma (eg. focus 7 indicated PDA). Regions of well-differentiated (eg focus 3) and moderately differentiated (eg focus 10) also show comparable staining.