Comparison of p53 and bcl-2 expression in initial, synchronous, and metachronous colorectal adenomas

To investigate the significance of p53 and bcl-2 expression in metachronous colorectal adenomas arising in the remaining colon after carcinoma resecti on, we analyzed p53 and bcl-2 expression immunohistochemically in initial a denomas (type I), synchronous adenomas with concurrent carcinoma (type II), and metachronous adenomas arising after resection of initial adenomas (typ e III) or carcinoma (type TV). The incidence of p53 immunoreactivity in typ e IV adenomas with mild dysplasia was significantly higher than that in typ e I, type II, or type III adenomas with mild dysplasia, bcl-2 immunoreactiv ity was more frequently detected in type TV adenomas with mild dysplasia th an in type I or type III adenomas with mild dysplasia, Coexpression of p53 and bcl-2 was detected in 16% of the type IV adenomas, this being a signifi cantly higher frequency than that seen in the type I, type II, or type III adenomas. These results suggest that the evaluation of p53 and bcl-2 in met achronous adenomas in the remaining colon after resection of carcinoma may be a useful biologic marker for assessing the risk of cancer development.