The proportion of neoplastic cells immunocytochemically positive for type IV collagenase (IVase), laminin receptor (LR), and Ki67 proliferation-associated antigen increased during the progression of human colon, gastric, and breast carcinomas. Thirty cases of colonic adenoma were compared with 30 cases of Dukes' A or B stage carcinoma and ten cases of Dukes' C stage carcinoma. The percentage of positive cells increased significantly (P less than 0.001) for all three antigens comparing carcinomas with adenomas and Dukes' C stage compared with Dukes' A/B stage. The same pattern of antigen correlation with progression was found with 40 human gastric carcinomas. Gastric carcinomas classified as well-differentiated advanced stage contained a significantly higher proportion of tumor cells positive for IVase (P less than 0.001), LR (P less than 0.001), and Ki67 (P less than 0.001) compared with well-differentiated superficial tumors. Gastric carcinomas classified as poorly differentiated superficial had a significantly higher proportion of cells positive for Ki67 (P less than 0.016), but not IVase (P less than 0.069) or LR (P less than 0.075), compared with poorly differentiated advanced tumors. Metastasis of colon and gastric carcinoma retained the immunostaining pattern of the primary tumors. Thirty cases of breast neoplasia were compared with 30 adjacent samples of normal duct epithelium. A positive correlation (P less than 0.001) was found for the immunoreactivity of all three antigens in the invasive carcinomas compared with the normal epithelium. Invasive ductal carcinoma and invasive lobular carcinoma had a significantly higher percentage of immunoreactivity for the three antigens compared with corresponding in situ lesions.(ABSTRACT TRUNCATED AT 250 WORDS)