To elucidate the relation between urokinase-type plasminogen activator
(U-PA) and metastasis in gastric cancer, we examined U-PA tissue stat
us immunohistochemically. Ninety-eight primary gastric cancer, prepare
d by AMeX method, were analyzed with anti-U-PA and anti-proliferating
cell nuclear antigen (PCNA) monoclonal antibody. In addition, DNA ploi
dy patterns were determined by cytofluorometer after staining with pro
pidium iodide. U-PA immunoreactivity can be observed as diffuse cytopl
asmic staining, as intensely outlined luminal borders or in desquamete
d cells in the lumens. U-PA expression-positive tumors showed higher i
ncidence of serosal invasion, lymph node involvement or larger tumors
than did U-PA negative ones. There was no correlation between U-PA tis
sue status and PCNA labeling rates or DNA ploidy patterns. Patients wi
th a U-PA positive tumor survived significantly shorter than those wit
h U-PA negative ones. These results may indicate that U-PA tissue stat
us is a useful biological prognostic indicator in gastric cancer. The
high malignant potential of U-PA positive tumors may be associated wit
h a rapid infiltrating capacity through gastric wall but not with a hi
gh proliferative activity.