Heritable T-Cell Malignancies are transplantable and can be easily visualized by fluorescent protein expression in leukemic cells (Modified from Frazer et al., 2009). GFP+ leukmias from shrek (srk; A, B, C), hulk (hlk; D, E, F), and oscar the grouch (otg; G, H, I) mutants were transplanted into irradiated wild-type hosts. By one week, GFP+ cells were seen at the site of transplantation (A,D,G). Subsequently, tumors spread locally (B,E,H) and then disseminated widely (C,F,I).