THE EXPRESSION OF P53 TUMOR-SUPPRESSOR PROTEIN DURING PROGRESSION OF GASTRIC AND COLORECTAL CARCINOMAS

The expression of p53 was immunohistochemically determined in sets of biopsies from primary and recurrent colorectal (12) and gastric (17) t umours that had progressed to more advanged stages in the following 6- 54 months. At presentation 7 carcinomas overexpressed p53 protein in t he cell nucleus and 22 tumours had normal, undetectable levels of p53. In most patients, the p53 phenotype was maintained during the process of tumour progression. In two gastric and two colorectal carcinomas p 53 overexpression was subsequently detected in recurrent tumour growth at the primary site and was also associated with the development of m etastases. These results suggests that in some cases p53 alterations m ay contribute to the conversion to malignancy and in others to tumour progression and metastatic capacity.