Clinical features of cystatin A expression in patients with pancreatic ductal adenocarcinoma. Issue 11 (8th October 2017) - Komura, Takuya
Abstract : Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy known, with an extremely poor prognosis due to the lack of an efficient diagnostic scheme and no radical treatment option, except surgery. Therefore, understanding the pathophysiology of, and finding a novel biomarker to detect, PDAC should be prioritized. We observed an increase in mRNA expression of the cysteine protease inhibitor cystatin A (CSTA) in CD4 + T cells in peripheral blood cells of nine patients with PDAC, compared with the expression in seven healthy volunteers. Moreover, we confirmed significantly higher CSTA mRNA expression in a larger cohort of 41 patients with PDAC compared with that in 20 healthy volunteers. Correspondingly, the serum CSTA concentrations in 36 patients with PDAC were higher than those in 37 healthy volunteers, and this increase was correlated with PDAC clinical stage. Furthermore, the expression of CSTA and cathepsin B, which is a lysosomal cysteine protease inhibited by CSTA, was observed in tumor tissues and tumor‐infiltrating immune cells in 20 surgically resected PDAC tissues by immunohistochemical staining. Expression of CSTA was detected in some tumor tissues and many tumor‐infiltrating immune cells. Cathepsin B expression was also observed in most tumor tissues and tumor‐infiltrating immune cells. In conclusion, CSTA and its substrate cathepsin B are involved in PDAC‐related inflammation. The increment of CSTA expression in peripheral blood of patients with PDAC may have a potential role as a PDAC immunopathologic biomarker. Abstract : Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy with extremely poor prognosis. In the current study, we have attempted to analyze expression focusing on CSTA and its related molecule cathepsin B, systemically, since we have observed that gene expression of CSTA in peripheral blood is affected by digestive system cancers. As overall result, we disclosed the feature of CSTA and cathepsin B expression in PDAC tumor tissue, and reflection on cells as well as sera in the peripheral blood.