OBJECTIVETo evaluate the expression of mitogen activated protein kinase phosphatase-1(MKP-1)in pancreatic cancer.

METHODSTotally 60 cases of normal pancreas, chronic pancreatitis(CP), and pancreatic cancer tissues were collected by operation in our hospital. Pancreatic tissues were analyzed by Northern blot analysis and Western blot analysis. Meanwhile, MKP-1 expression was detected in 6 pancreatic cancer cell lines by Western blot analysis.

RESULTSNorthern blot analysis of total RNA revealed relatively low MKP-1 mRNA expression in 7 of 20(35%)normal pancreatic samples. In the remaining 13 samples, the MKP-1 mRNA was absent to faint detectable. In 7 of the 20 CP samples, MKP-1 was demonstrated moderate to high expression. In contrast, 12 of 20(60%)pancreatic cancer samples MKP-1 mRNA was expressed at high levels, whereas in the remaining 8 cancer tissues this mRNA moiety was present at low to moderate levels. Densitometric analysis with normalization to 7S revealed that the median level of MKP-1 mRNA in CP and cancerous tissues was increased by 6.2 folds(P=0.035)and 8.1 folds(P=0.016)in comparison with the median level in the normal pancreatic samples, respectively. Overexpression of MKP-1 was also found in 6 pancreatic cancer cell lines, in which the expression of MKP-1 was slightly lower in one pancreatic cancer cell line but high in the remaining 5 cell lines.

CONCLUSIONSMKP-1 is over-expressed in pancreatic cancer, CP tissues, and pancreatic cell lines. It is speculated that MKP-1 may play an important role in tumorigenesis of pancreatic cancer.