ABL1 and neoplasm: The apparent tumor burden of all four mice was ~1 X 109 photons/sec prior to sacrifice, yet the dissemination of Abl kinase-deficient tumor cells appeared qualitatively substantially increased compared to vector control tumor cells (Figure 1C), despite the fact that the mice harboring vector control tumor cells were euthanized ~2 additional weeks later than the mice harboring the Abl-deficient tumor cells.