SLIT2 and neoplasm: To assess the antitumor impact of Slit2 via changes in the bone marrow, independent of systemic effects, we studied the effect of Slit2 on macrophage polarization and overall tumor growth in PyMT mice that were irradiated with a sublethal dose to achieve myeloablation and later received an allograft with bone marrow cells from luciferase-expressing mice (ROSA-Luc).