The murine leukemia P388 is being evaluated as a potential model for testicular leukemia since this tumor is responsive to most of the drugs used to treat childhood acute lymphocytic leukemia. Infiltration of P388 cells into testes occurs, but the tumor cells plateau at about 105 to 106 cells/testes, a number inadequate to produce macroscopic disease. Therefore, disease could be evaluated only by bioassay, i.e., suspending and implanting the testes into recipient mice. In advanced disease (at plateau), the tumor cells are responsive to Adriamycin; when the tumor cells are proliferating in testes, they respond to treatment with Adriamycin, methotrexate, and vincristine. Therefore, in this model, the testicular leukemia cells do not appear to reside in a pharmacological sanctuary.
Supported by Grant CA-28034 from the National Cancer Institute, and by development funds from the Department of Pediatrics, The University of Texas Medical School at Houston.