Relative changes in tumor volumes for vehicle, G-CSF, IL-12 pre-only, IL-12 post-only and IL-12 pre-post treatment groups following radiation. Changes in tumor volumes over the course of the experiment are shown for the EL4 lymphoma tumor model (A) and the Lewis Lung cancer tumor model (B). Mice in both tumor models were given 625 rad at day 1. Mice in the EL4 lymphoma tumor model were given a second dose of radiation on day 22 (560 rad), and mice in the Lewis Lung cancer tumor model also were given a second dose of radiation on day 22 (750 rad) following the initial radiation dose. Tumor measurements were made on the days indicated by measuring the tumor diameter and converting this measurement into tumor volume using a spherical volume formula. In the EL4 lymphoma model, all IL-12 treatment groups significantly reduced tumor growth (%T/C < 50%) as compared with the PBS and G-CSF controls at the end point of tumor volume evaluation. In the Lewis lung cancer model, only the IL-12 post-only treatment group gave a significant reduction in tumor growth (%T/C < 50%) at the end point of tumor volume evaluation. The change in the slope of the curve for days 19–23 as compared to days 23–27, which occurs after the second radiation, may indicate a radio-sensitizing effect of the indicated treatments.