We subcutaneously inoculated parental and glioma cells genetically engineered to express interleukin-2 (SR/IL-2) into syngeneic mice. The tumor growth of the transfectants was slower than that of the parental cells. We then stereotactically inoculated transfectants into the brains of mice. The survival of the mice injected with parental cells was shorter than that of the mice inoculated with transfectants. SR/IL-2 cells were inoculated subcutaneously into the flank of mice, after which rmIL-12 was administered intraperitoneally (i.p.). The resultant transient tumor growth was followed by regression. rmIL-12 or saline were then injected i.p. into mice that had been inoculated in the brain with SR/IL-2 cells. There was no significant difference in survival time between the treated and control groups.