CD80 and colorectal cancer: The significant overexpression of CD80 in the colonic mucosa of patients with ulcerative colitis (UC) and dysplasia as opposed to CD80 down-regulation in non-inflammatory colon cancer [4–6] have led to the hypothesis that the lack of positive co-stimulatory molecules is one of the main mechanisms by which colorectal cancer (CRC) escapes immune surveillance [7].