Several studies have implicated the extracellular matrix-degrading metalloproteinases (MMPs) as essential agents in tumor cell invasion and metastasis. In the present study, we have investigated the patterns of expression of a number of MMPs and their specific tissue inhibitors (TIMP-1 and TIMP-2) in human colonic tissue samples that represent various stages of progression from adenomas showing different degrees of dysplasia to adenocarcinomas. We assessed levels of mRNA by Northern blot analysis and the results were measured semiquantitatively by densitometry. In total, we analyzed nine adenomas of varying size and with varying degrees of dysplasia, three adenomas with adenocarcinoma (malignant polyps), and five adenocarcinomas. Although expression of MMP and TIMP mRNA was highly intercorrelated, transcripts for stromelysin 3 and TIMP-2 (high) showed the strongest relation to the neoplastic process. Detection of stromelysin 3 mRNA accompanied a diagnosis of severe dysplasia or malignancy, whereas levels of TIMP-2 (high) mRNA transcripts permitted finer distinctions on the neoplastic continuum. These data indicate changes within extracellular matrix acquired during the process of malignant transformation of human sporadic colorectal neoplasia.