Figure 5.

Immunohistological expression pattern of CD97 on cryosections of colorectal normal tissue and carcinoma. A: Normal epithelial cells are CD97-negative (open arrow), whereas tumor cells express the antigen (arrow). Note the strong staining of smooth muscle cells in the lamina muscularis mucosae and the muscular coat (asterisk). B: Stronger cytoplasmic and membranous expression of CD97 in scattered tumor cells or tumor cells groups (arrow) surrounded by stroma compared to tumor cells located in tumor glands or solid tumor trabecula (open arrow). C: Stronger membranous CD97 staining of the outer parts of tumor cells at the tumor margin or invasion front (arrow) and weaker or no membrane expression on tumor cells within the center of the carcinoma. Moreover, there is a group of tumor cells seeming to detach from the tumor formation with stronger CD97 expression (open arrow). Scale bars: 100 μm (A); 50 μm (B and C).