Abstract
Forty-four frozen samples of surgically removed colorectal cancer were subjected to: (1) c-erbB-2 protein staining with a monoclonal antibody to c-erbB-2 protein and (2) analysis of nuclear DNA content by flow cytometry. The overall c-erbB-2 protein-positive rate was 25/44 (56.8%). There was no significant difference in the rate between well-differentiated adenocarcinoma (19/34), moderately differentiated adenocarcinoma (4/7). In relation to the depth of cancer, the incidence of c-erbB-2 protein was 0/1 in m cases, 1/2 in sm cases, 1/2 in pm cases, 6/10 i ss (a1) cases, 15/23 in s (a2) cases, and 2/6 in si (ai) cases. There was also no significant difference in the rate between patients without (16/26) and those with lymph node metastasis (9/18). The incidence tended to be higher in cases with lymphatic vessel invasion: 2/8 in lyo cases, 23/36 in ly1-3 cases. The incidence was 1/4 at stage I, 11/16 at stage II, 3/6 at stage III, 1/8 at stage IV and 9/10 at stage V. Aneuploidy was observed in 28/42 cases. The incidence of c-erbB-2 protein did not differ significantly in diploidy cases (11/14) from that in aneuploidy cases (14/28). These results suggest that the expression of c-erbB-2 protein in colorectal cancer is associated with distant metastasis, and that it serves as an index of the malignancy level of colorectal cancer independent of DNA ploidy patterns.
