Increased angiogenin expression in obstructive chronic pancreatitis surrounding pancreatic cancer but not in pure chronic pancreatitis

We previously demonstrated the increased expression of angiogenin (ANG) in pancreatic cancer and its relation to cancer aggressiveness; however, the e xpression patterns and the roles of angiogenin in chronic pancreatitis are still unknown. We investigated the expression of ANG both in the tissues an d in the sera of chronic pancreatitis patients (pure chronic pancreatitis) by using in situ hybridization, Western blot analysis, and enzyme-linked im munosorbent assay. In situ hybridization revealed no detectable ANG messeng er RNA (mRNA) signals in all tissues of pure chronic pancreatitis and norma l pancreas. Only a small amount of protein band expression was obtained in all of the protein lysates of pure chronic pancreatitis and normal pancreas . Accordingly, there was no significant difference between the mean serum A NG concentration of chronic pancreatitis patients (352.1 +/- 72.5 ng/ml) an d that of healthy volunteers (357.6 +/- 45.2 ng/ml). By contrast, acinar ce lls and interstitial fibroblasts in the tissues surrounding pancreatic canc er showed increased ANG mRNA expression. Strong protein band expression was obtained in the protein lysates of pancreatic cancer surrounding tissue, a nd mean serum ANG concentration was increased in pancreatic cancer patients . These findings suggest that ANG expression is increased in pancreatic can cer surrounding tissue but is not increased in pure chronic pancreatitis, a nd that ANG is potentially involved in the pancreatic cancer microenvironme nt rather than the establishment of pure chronic pancreatitis.