Expression of CD68 and Fas Ligand in Colon Mucosa of Patients with Inflammatory Bowel Disease as Prognostic Markers of Cancerogenesis

As it is known, colon carcinogenesis is associated with the inflammatory bowel disease (IBD). Colorectal cancer (CRC) being observed in 5.5-13.5 % of patients with ulcerative colitis (UC) and in 0.4-0.8 % of patients with Crohn disease (CD). The gut mucosa of patients with CD, but not with UC, as well as the stroma of CRC have elevated numbers of CD68(+) macrophages. It is known also that the expression of Fas Ligand (FasL), representing another branch of immunoreactivity, in the lesions of CRC and UC but not of CD is upregulated. The fact that enterocyte apoptosis is increased in lesions of CD and lymphocytes in UC are resistant to Fas-mediated apoptosis can be the keypoint for understanding the hypothesis [17], suggesting that cells express FasL and are able to kill Fas-expressing activated lymphocytes and escape rejection by the immune system, which can be the basis for differences in association of UC and CD with CRC. The aim of this study was to evaluate the number of CD68(+) macrophages and to analyze FasL expression in colon mucosa of patients with UC, CD and CRC in order to assess its value for prognosis of CRC. Expression of CD68 and FasL was analyzed immunohistochemically in the samples of colon mucosa taken from the affected areas of 4 patients with UC, 6 patients with CD and 10 patients with CRC. In addition in 7 CRC patients the samples taken from unaffected areas were analyzed. We find average expression of FasL in both unaffected and affected areas of CRC patients was higher than in CD patients (p = 0.04, p = 0.00). Average expression of FasL in affected areas of CRC patients was higher (p = 0.02) than in UC patients and the same (p = 0.23) as in unaffected areas of CRC patients. The revealed associations support the possibility to use expression of CD68 and FasL as prognostic markers for transformation of IBD to CRC.