Infection of precursors ex vivo with an adenovirus constructed to secrete a soluble form of the colony-stimulating factor-1 receptor CD115 that inhibits macrophage viability and migration in vitro significantly decreases the number of TAMs in xenografts (p < .05), reduces proliferation (p < .01) and vascular density (p < .03), and suppresses the growth of xenografts (p < .03). This evidence concerns the gene CSF1R and infection.