Currently, the most accurate prognostic indicator in gastric cancer is stage. Studies on proliferating cell nuclear antigen (PCNA) in gastric cancer have demonstrated that the PCNA labeling index correlates with depth of invasion, organ metastasis, vascular invasion, and tumor stage, suggesting that this marker may be a valuable prognostic factor. Epidermal growth factor (EGF) promotes the growth of cells of both ectodermal and mesodermal origin, and plays an important role in cellular proliferation and differentiation. Furthermore, there has been increasing evidence that growth factors and their receptors are involved in carcinogenesis. The aim of this study was to investigate the correlation between expression of the EGF-receptor (EGF-r) and proliferative activity (PCNA labeling index) in gastric cancer by immunohistochemical analysis. Our preliminary results on 56 gastric cancers indicate that the PCNA labeling index correlates with EGF-r immunoreactivity. Furthermore, survival was significantly lower in patients with EGF-r positive tumors and a high PCNA labeling index. These in situ observations suggest that EGF-r may play an important role in the growth regulation of human gastric carcinomas.