We demonstrated that four human oesophageal squamous cell carcinoma cell lines (TE8, TE9, TE10 and TE11) produced matrix metalloproteinase-1 (proMMP-1/tissue collagenase), 2 (ProMMP-2/'type IV collagenase'), 3 (proMMP-3/stromelysin), and 9 (proMMP-9/92-kDa gelatinase) as members of a matrix metalloproteinase (MMP) family, which degrades extracellular matrix macromolecules. Under normal culture conditions, in immunoblot analysis, proMMP-1 of M(r) = 53,00 was detected in one cell line (TE8), proMMP-2 of M(r) = 72,000 in three cell lines (TE9, TE10, and TE11), and proMMP-3 of M(r) = 57,000 in all four cell lines. In addition to these enzymes, in enzymography, a gelatinolytic activity around M(r) = 92-kDa, likely to be proMMP-9, was detected in only one cell line (TE10) under normal culture conditions. When these cell lines were treated with epidermal growth factor (EGF), however, the agent stimulated three cell lines (TE8, TE10 and TE11) to produce proMMP-9 in a dose-dose dependent manner. Oesophageal carcinoma-conditioned medium stimulated oesophageal fibroblasts to produce proMMP-1, -2, and -3, suggesting that the interaction between oesophageal carcinoma and stromal fibroblasts also plays a role in the production of MMPs by the latter. Our present study illustrates that oesophageal squamous cell carcinoma produces a variety of MMPs including proMMP-1, -2, -3, and -9 in vitro, suggesting that the ability of MMP production of the tumour may play an important role in its malignant behaviour and that the production of proMMP-9 may be regulated by EGF via overexpression of EGF receptors.