BACKGROUND: Alterations in the activity of transforming growth factor beta (TGF-beta) in humans have been implicated in fibrosis, immunosuppression, development of cancer, and other disorders. Scirrhous gastric carcinoma is characterized by cancer cells that infiltrate rapidly in the stroma with extensive growth of fibroblasts and fibrous tissue. Hence, the majority of studies examining the role of TGF-beta in gastric carcinoma have focused on scirrhous carcinoma.METHODS: We undertook a retrospective immunohistochemical study of gastric carcinoma in order to characterize TGF-beta expression in malignant gastric lesions and to determine whether TGF-beta expression was related to disease progression.RESULTS: TGF-beta expression in scirrhous gastric carcinomas was significantly higher than that in nonscirrhous gastric carcinomas. In patients with advanced gastric carcinoma with surgically curative resection, TGF-beta expression was significantly higher in those patients who developed peritoneal recurrence after surgery than in those who did not develop such recurrence. Patients with TGF-beta expression-positive tumors had significantly poorer survival than did those with TGF-beta expression-negative tumors ( P = 0.017). In addition, multivariate Cox proportional hazard model analysis showed that TGF-beta immunohistochemical status was an independent prognostic factor ( P = 0.0031).CONCLUSION: These data suggest that TGF-beta may contribute, in part, to the variations in histogenesis and to the prevalence of peritoneal dissemination in gastric carcinoma.