P53 AND BCL-2 PROTEIN EXPRESSION IN RECTOSIGMOID ADENOMAS

Objective: The aim of this study was to evaluate whether p53 or bcl-2 protein expression in rectosigmoid adenomas is associated with histolo gical characteristics of the adenomas and with presence of synchronous advanced proximal neoplasms, Methods: Seventy-six average-risk patien ts who underwent total colonoscopy and had rectosigmoid adenoma(s) wer e studied, An adenoma was considered advanced if villous histology and /or severe dysplasia and/or diameter >1 cm were present, p53 And bcl-2 protein expression was immunohistochemically examined using specific monoclonal antibodies, Results: p53 Protein was detected in 43 % and b cl-2 in 93 % of the 76 rectosigmoid adenomas, Advanced compared with n onadvanced adenomas were significantly more frequently p53-positive (2 8 of 44 or 63.6% vs five of 32 or 15.6%, p < 10(-4)) or had a bcl-2 sc ore of 12 (20 of 44 or 45.5% vs five of 32 or 15,6%,p = 0.007), Proxim al advanced neoplasms were mainly found in patients with rectosigmoid adenomas positive for p53 and with a bcl-2 score of 12 (six of 17 or 3 5.3 % vs 2/59 or 3.4 %, OR: 15.6, p = 0.001) and in particular in thos e with advanced rectosigmoid adenomas positive for p53 and with a bcl- 2 score of 12 (six of 13 or 46.2 % vs two of 31 or 6.5 %, OR: 12,4, p = 0,007), Conclusion: p53 Expression and bcl-2 protein overexpression in rectosigmoid adenomas are associated with advanced histology and a high risk of synchronous advanced proximal colon neoplasm, (C) 1998 by Am, Cell, of Gastroenterology.