Fig 1: Expression of DAO and ODC in different colonic pathological conditions. (a) Morphological aspect of colonic carcinoma with areas of squamous metaplasia. (b) The same section stained with anti-DAO polyclonal antibody; note the weak positivity diffused particularly in well-preserved mucosal epithelium. (c) In a consequent section stained with anti-ODC pAb the strong expression of the enzyme is observed in metaplastic undifferentiated areas. (d) Morphology of granulomatous colitis with severe crypts involvement and areas of subepithelial fibrosis. (e) The expression of DAO in a consequent section shows a continuous and strong expression in the superficial epithelium, but only occasional and spotted strong stain in epithelium lining the crypts. (f) Weak and focal expression of ODC in a successive section evidences the low concentration of the enzyme in colonic epithelium during the granulomatous phlogosis. ((a) and (d) H&E; (b), (c), (e), and (f) IHC stain, Meyer's haematoxylin counterstain; (a), (b), and (c) bar = 300 µm; (d), (e), and (f) bar = 600 µm).