Possible relationship between the expression of membrane-associated phospholipase A2 and the proliferation of interstitial tissue in human pancreatic cancer

The immunohistochemical localization of membrane-associated phospholipase A2 (M-PLA2) in normal human pancreases and 30 cases of pancreatic ductal carcinomas was investigated. In pancreatic ductal carcinomas, the immunoreactivity was observed in 25 cases (83%). Among the clinocopathological factors of pancreatic cancer, the incidence of expression of this enzyme is significantly higher in infiltrative type cancers. Furthermore, the expression of M-PLA2 was significantly increased in tumors, which had a larger amount of interstitial tissue. On the other hand, human M-PLA2 added exogenously to the fibroblast cell lines Swiss 3T3 and BALB/3T3 was found to augment their DNA synthesis. The stimulation of DNA synthesis was not affected by treatment with indomethacin. These results suggest that this enzyme could be involved directly in the proliferation of interstitial tissue through its own function. [Copyright &y& Elsevier]