Adenomas of the colon: overexpression of p53 protein and risk factors.

BACKGROUND AND STUDY AIMS

p53 gene mutation and the ensuing overexpression of its protein is one of the steps related to colorectal carcinogenesis. This study analyzed the relationships between immunohistochemically detected p53 protein accumulation in colonic adenomas and morphological and clinical indicators of risk of malignant transformation and relapse.

PATIENTS AND METHODS

A total of 100 endoscopically resected sporadic colonic adenomas (nonpolyposis) from 79 patients were retrospectively studied by using archival paraffin tissue blocks. p53 protein immunohistochemically detected was related to morphological adenoma risk factors (size, histological type and dysplasia) and in patients to neoplastic colonic pathology (NCP), such as previous adenomas/carcinomas or coexistent adenomas.

RESULTS

There was a correlation between p53 expression and the grade of dysplasia but not with size or histological type in adenomas. NCP data was present in 52.5% of patients with p53 positive adenomas, and only in 25.6% of patients with p53 negative adenomas. This difference remains even in those with low-grade dysplastic lesions. When coexistent adenoma and previous adenoma/carcinoma data were analyzed separately, similar results were obtained.

CONCLUSIONS

The presence of previous and/or coexistent NCP was more frequent in patients with p53 expressing adenomas, even in low-grade dysplastic lesions, which probably could be a high risk subpopulation. Its follow-up may be eventually reviewed.