Abnormal rectal cell proliferation and p52/p35 protein expression in patients with ulcerative colitis

We evaluated the presence of cell proliferation and antigenic abnormalities in rectal biopsies from 37 patients affected by ulcerative colitis and 15 controls. The study was carried out by thymidine labeling and immunochemistry, using antibodies against specific cytoskeletal-associated proteins (p52, p35, alpha-actinin). Among ulcerative colitis patients, 24 had an immunofluorescence pattern similar to that of controls, while 13 showed an abnormal distribution of one or more proteins (p52 alone or p52 and either p35 or alpha-actinin) within the rectal crypts. Patients showed a shift of the proliferative compartment towards the top of the rectal crypts compared with controls. This finding was more evident in patients with p52 or p35 abnormalities. Proliferative and antigenic defects were not related either to age or the duration of colitis. These phenotypic changes might be a biomarker of increased risk of colon cancer in ulcerative colitis.