[Immunohistochemical expression of p53 oncoprotein in large bowel adenomas and carcinomas].

BACKGROUND

Colorectal carcinoma is the sixth cause of death in Chile. Half of malignant tumors in humans have genetic alterations in protoncogenes, tumor suppressing genes or both. One of the most frequent alterations is that involving p53 tumor suppressor gene.

AIM

To study, using immunohistochemical methods, alterations in p53 gene expression in colorectal carcinomas and adenomas.

MATERIAL AND METHODS

A random sample of 28 large bowel adenomas and 44 carcinomas was studied. Determination of p53 protein was made with an immunohistochemical method using monoclonal antibodies. Patients were followed for a mean of 36 months (range 1 to 100 months).

RESULTS

p53 immunostaining was obtained in one adenoma (3.5%) and in 18 carcinomas (41%, p = 0.01). There were no differences in survival during follow up, between cancer patients that expressed or did not express p53 protein.

CONCLUSIONS

About half of colorectal tumors have immunohistochemical expression of p53 protein, as published abroad. We did not find a prognostic value for this protein in our sample.