To ascertain the role of T cell-derived VEGF-A in a spontaneous transgenic model of cancer, we employed the MMTV-PyMT model of multifocal mammary adenocarcinoma (Guy et al., 1992) backcrossed to a C57/Bl6 background (Davie et al., 2007). The gene discussed is VEGFA; the disease is breast adenocarcinoma.