Hepatocyte growth factor (HGF) induced scattering and cell migration of human gastric adenocarcinoma MKN-74. HGF also significantly promoted the growth of MKN-74 cells in a dose-dependent manner, although HGF is reported to be antiproliferative for the growth of tumor cell lines. This result indicates that HGF stimulates cell proliferation of not only normal epithelial cells but also certain carcinoma cells. Furthermore, transforming growth factor-beta (TGF-beta), which is recognized to inhibit the growth of most epithelial cells, additively enhanced both the cell proliferation and migration induced by HGF. These additive effects of HGF and TGF-beta may be responsible for the tumor invasiveness and uncontrolled growth of certain types of carcinoma.