Proteinase-activated receptor-2 (PAR-2) is expressed in various tissues, including cancer lesions. However, the functional consequences of PAR-2 expression in cancer cells, especially in pancreatic cancer cells, are poorly understood. To clarify the biological significance of PAR-2 signaling in pancreatic cancer, we examined the production of growth factors and cytokines, such as IL-6, IL-8, bFGF, TGF-beta1, and VEGF, by specific ELISAs. Two human pancreatic cancer cell lines, SUIT2 and MiaPaCa2, which have been shown to express PAR-2, were stimulated by trypsin and PAR-2 activating peptide (PAR-2AP: SLIGKV-NH2). After 24 h, the culture supernatants were collected and specific ELISAs were performed. Although no significant changes were observed in the release of IL-6, bFGF, TGF-beta1, or VEGF, that of IL-8 was significantly up-regulated by PAR-2 agonists in a dose-dependent manner. In addition, IL-8 receptor expression was found in pancreatic cancer cells and fibroblasts. These results suggest that the PAR-2 signal up-regulates IL-8 release from pancreatic cancer cells. This up-regulated IL-8 has an effect on the pancreatic cancer cells in an autocrine manner and on the fibroblasts in a paracrine manner. Thus, this signal might contribute to tumor progression and characteristic fibrosis in pancreatic cancer.