RESUMO
Sporadic adenomas are said to exhibit an orderly growth pattern with a reversal of proliferative and apoptotic cell distribution as compared with normal colonic crypts. Dysplastic polyps of patients with ulcerative colitis (UC) may represent dysplasia-associated lesions or masses (DALM) with a high associated cancer risk, or, alternatively, may represent sporadic adenomas. Histologic criteria to differentiate between sporadic adenomas and DALM have not focused on the balance between cell renewal and cell loss. The expression of the novel anti-apoptosis gene product, survivin, and the proliferation markers, Ki-67 and Y-box binding protein (YB-1), were investigated by immunohistochemical localization in sporadic adenomas and DALM lesions of patients with UC. In adenomas, KI-67 was expressed preponderantly at the luminal aspect of the polyp, whereas its expression was diffuse in DALM. Survivin was detected diffusely in both adenomas and DALM. YB-1 showed positive staining in the deep aspect of adenomatous glands but only to a minor degree at the surface, whereas both deep and diffuse expression patterns of YB-1 were seen in DALM. The authors conclude that DALM and sporadic adenomas exhibit different patterns of cellular proliferation and that molecular markers of cell proliferation, Ki-67 and YB-1, may be useful to distinguish sporadic adenomas from DALM. However, the similar expression of survivin suggests that the underlying mechanisms that regulate apoptotic cell death are uniform in these lesions.