FIGURE 3

Drebrin distribution in different epithelial skin tumors. Immunohistochemical reactions on sections through aldehyde-fixed, paraffin-embedded tissues are shown. (A) In basal cell carcinoma (BCC), strongly positive drebrin reactions throughout the tumor are observed, whereas the overlying epidermis is drebrin-negative (brackets). In contrast, in squamous cell carcinoma (SCC) (B) and in keratoacanthomas (C, D), heterogeneous expression patterns are seen: certain groups of cells exhibit marked drebrin enrichment at cell borders (B, C), whereas others appear to be drebrin-negative (B, D). In C and D, two different regions of the same keratoacanthoma, both containing horn pearls (HP), are shown: although the HP-surrounding tissue in C is positive, that shown in D is negative. The asterisks in D designate drebrin-positive blood vessels, here also serving as an internal positive control. A–D, antiserum dreb4.1gp; A'–D', phase-contrast images. Scale bars: 25 m.