p53 protein accumulation and colonic adenoma recurrence

The prognostic value of p53 protein accumulation in colonic adenomas is still controversial. The aim of the present study was to determine whether the evaluation of p53 protein accumulation in newly diagnosed colonic adenomas could predict the development of metachronous adenomas.

Fifty-five patients who underwent prior endoscopic polypectomy for colonic adenomas were colonoscopically re-evaluated at 24-38 months after index colonoscopy. In cases with more than one adenoma, the one with the greatest diameter and the most serious histology was taken into account. p53 protein expression was immunohistochemically examined using specific monoclonal antibody.

p53 protein was detected in 41.8% of the 55 index adenomas. Recurrent adenomas were present in 21 patients (38.2%). Metachronous adenomas were present in 56.5% of patients with p53-positive index adenomas and in 25% of those with p53-negative index adenomas (odds ratio 3.90, P = 0.018). Among patients with 1 or 2 index adenomas, metachronous adenomas were found in 50% of those with p53-positive index adenomas and in 22.6% of those with p53-negative index adenomas (odds ratio 3.43, P= 0.042). Multivariate stepwise logistic regression analysis revealed that number of index adenomas per patient (1 or 2 versus > 2) and p53 expression (positive versus negative) in index adenomas contain independent prognostic information for adenoma recurrence (chi2 = 8.2, P= 0.004 and chi2 = 4.08, P = 0.04 respectively). Patients aged < 60 years developed recurrent adenomas relatively more frequently if they had a p53-positive index adenoma (P= 0.068). In the subgroup of patients aged < 60 years with 1 or 2 index adenomas, the recurrence of adenomas was more frequent in those with a p53-positive index adenoma but the difference did not reach statistical significance (P= 0.13).

Our data suggest that p53 expression in index adenomas is associated with recurrent colonic adenomas.