Detection of serum MMPs in tumor-bearing hamsters.

Background/Purpose Matrix metalloproteinases (MMPs) have been implicated as playing an important role in cancer invasion and metastasis. MMPs have been identified in various malignancies, including pancreatic duct adenocarcinomas. Methods We investigated the circulating level of MMP-2 and MMP-9 in sera from Syrian golden hamsters into which hamster pancreatic duct adenocarcinoma tissues had been transplanted subcutaneously (HPDt hamsters). Northern blot analysis and gelatin zymographic analysis were performed to detect the expression of MMPs and that of tissue inhibitors of metalloproteinases (TIMPs) in HPDt hamsters. Results Northern analysis revealed overexpression of MMP-2, MMP-9, and TIMP-2 mRNAs in subcutaneous tumors of HPDt hamsters as compared with normal pancreatic tissue. Sera from HPDt hamsters possessed significantly higher levels of serum MMP-2 and MMP-9 than control sera, as determined by gelatin zymographic analysis, and there was a significant correlation between tumor growth and serum MMP levels. Conclusions These results indicate that overexpression of MMP mRNAs is involved in the progression of pancreatic duct adenocarcinomas, and that MMP protein expression in hamster sera is associated with the presence of pancreatic duct adenocarcinoma cells. The findings also suggest that serum MMPs could be useful markers for monitoring patients with pancreatic duct adenocarcinomas.