The nuclear DNA ploidy pattern and c-erbB-2 oncoprotein expression in primary and metastatic lesions were investigated using paraffin-embedded materials from 44 cases of colorectal carcinoma with hepatic metastases and 45 cases without hepatic metastases. The frequency of aneuploidy and positive staining of c-erbB-2 in primary tumor with hepatic metastases were significantly higher compared with those without hepatic metastases (p less than 0.05). There were significant correlations between diameter of metastases and DNA ploidy pattern of the metastases and between metachronous metastases, degree of metastases, vessel involvement and DNA ploidy pattern of the primary tumor. Positive staining of c-erbB-2 was detected more frequently with the advancement of depth of tumor invasion. There was no significant correlation between DNA ploidy pattern and c-erbB-2 expression. In the survival of patients whose primary tumor and hepatic metastases were resected, it was shown that DNA ploidy pattern of metastases was the most important independent prognostic factor. Expression of c-erbB-2 in primary tumor predicted the hepatic metastases.