Clinical relevance of proliferation biomarkers and p53 expression in rectal mucosa and sporadic colonic adenomas: a prospective study.

Background/Aims: Prespective study to evaluate D the pattern of proliferation biomarkers and p53 expression in rectal mucosa and adenomatous tissue, and 2) the clinical relevance of these biomarkers as predictors for adenoma recurrence. Methodology: 40 patients with sporadic adenomas underwent colonoscapic polypectomy and rectal biopsies. Assessment of proliferation biomarkers -Ornithine decarboxylase, PCNA and Ki-87 - was done in adenomas and rectal mucose, while p53 was performed in adenomas. After polypectomy, 34 adenoma patients were followed for 36 months to detect metachranous polyps, 20 controls underwent colonescopy and rectal biopsies, with assessment of proliferation biomarkers. Results: Mean values of ornithine decarboxylase. PCNA and Ki-67 in rectal mucosa from adenoma patients were not significantly different when compared with the control group. The expression of these biomarkers was significantly increased in adenomas versus rectal mucosa. Only 6 (15%) out of 40 adenomas were found to overespress p53 protein. During follow-up, recurrent polyps were detected in 12 patients (relapsing group). Mean values of ornithine decarboxylase, detected at index colonoscopy, were not significantly higher in relapsing group versus non-relapsing group. Mean values of PCNA and Ki-67 detected in adenomas at index colonoscopy were significantly higher in relapsing group when compared with non-relapsing group. Adenoma recurrence was observed in all patients with p53 overexpression. Conclusions: Ornithine decarboxylase, PCNA and Ki-67 expression in rectal mucesa did not show clinical relevance. Yet, increased expression of PCNA or Ki-67 in adenomatous tissue may be a predictor of adenoma recurrence. Positive p53 might have the same predictive value.