Villin immunoexpression in normal colonic mucosa and in colorectal carcinoma using immunohistochemical labelling with antivillin antibody with diaminobenzidine used as the chromogen and haematoxylin as counterstain. Magnification used was 200x. (a) Villin expression in normal colonic crypts showing a well-organised brush border pattern together with minor cytoplasmic dots in all crypts. (b) Expression in a well-differentiated tumour; a strong staining is shown in both cytoplasm and brush border (mixed pattern). (c) Villin expression in a moderately differentiated colorectal carcinoma; staining is shown in both cytoplasm and brush border (mixed pattern) with less extent and intense staining than in (b). (d) Villin expression in a poorly differentiated colorectal carcinoma showing very minor cytoplasmic staining with no membranous staining.