The concentration of group II phospholipase A2 was measured in blood plasma samples before and after liver transplantation in a 27-year-old woman who suffered from a massive epitheloid hemangioendothelioma of the liver. The pretransplantation concentration of group II phospholipase A2 was 830 microg/L, which is markedly above the upper limit of the reference interval (10.8 microg/L). After the transplantation, there was a dramatic decrease in the group II phospholipase A2 level (33 microg/L on the first posttransplantation day). In situ hybridization of mRNA and immunohistochemistry revealed synthesis of group II phospholipase A2 in hepatocytes in non-neoplastic areas of the liver. Tumor cells did not contain group II phospholipase A2. The results indicate that group II phospholipase A2 circulating in blood plasma originates in hepatocytes.