Studies on acute myelomonocytic leukemia in LBF1 rats.

Granulocytic leukemia was induced in Long-Evans (LE) rats by using the Huggins and Sugiyama method. After serial passage the cells became transformed. The newly transformed cells could be transplanted to LBF1 hybrid rats and observed more readily. A quantity of 10(8) cells/100 g body weight was injected intravenously and after 2-3 weeks myelomonocytic leukemia developed. By examining the bone marrow, spleen and lymph nodes, cytochemical tests verified this transformation. Transplanting 10(2)-10(4) cells under the renal capsule, a quickly growing solid tumor was observed, which caused metastasis to the parathymical lymph nodes and peritoneum. The investigation of oncogene expression for the myc and ras families revealed the presence of myc p62 and ras p21 oncoproteins in the tumor cells by using monoclonal antibodies in immunohistochemical tests. LBF1 rats proved to be good models in obtaining solid tumor growth and myelomonocytic leukemias, equivalent to human M4-M5 type leukemia.