CD68 immunostaining in human colon tissues. 7a CD68 immunostaining in healthy tissues (A), ulcerative colitis (B), adenomas (C) and adenocarcinomas (D) shows a growing expression of intensity, percentage of positive cells and density in stromal compartment (magnification ×400). 7b Expression of CD68 in the stromal compartment of the different groups. In all groups CD68 is significantly increased 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).