CD31 staining in human colon tissues. 9a Immunohistochemistry for CD-31 in healthy tissue (A), ulcerative colitis (B), adenomas (C) and adenocarcinomas (D) showed a correlation between dysplastic condition and expression of the marker. From ulcerative colitis to adenocarcinoma there is an increase in vascular density and intensity of marker expression (magnification ×400). 9b Different expression of CD-31 (in endothelial compartment) in healthy tissues, ulcerative colitis (UC), adenomas (AD) and adenocarcinomas (AC) show that the increasing grade of dysplasia directly correlates increased vascularization. In all groups CD31 is significantly increased with respect to healthy tissues (mean ± SEM; **P < 0.01, *** P < 0.001). HT = healthy tissues (N = 16); UC = ulcerative colitis (N = 13), AD = adenomas (N = 34; 29 low and 5 high grade), AC = adenocarcinomas (N = 53; 7 T1, 10 T2, 33 T3, 3 T4).