Bcl-2 and p53 expression in metachronous colorectal adenomas compared with initial adenomas in relation to the degree of dysplasia

To investigate the significance of p53 and bcl-2 expression in metachronous colorectal adenomas arising in the remnant colon after resection of carcinoma, we analyzed initial adenomas (type I), metachronous adenomas arising after removal of an initial adenoma (type II), and metachronous adenomas arising after resection of carcinoma (type III) for p53 and bcl-2 expression using immunohistochemistry. Positive staining for p53 or Bcl-2 was more common in type III adenomas with mild dysplasia than that in type I or type II adenomas with mild dysplasia. The incidence of coexpression of p53 and Bcl-2 was significantly higher in type III adenomas compared to type I or type II adenomas. These results suggest that expression of p53 and Bcl-2 in metachronous adenomas arising after resection of carcinoma may indicate the potential for malignant transformation, even though histological examination shows only low grade dysplasia.