MPEG1 and neoplasm: In addition, the possibility of using transgenic embryos with GFP-labelled vasculature (Tg:Fli1a) [124], or mCherry-labelled macrophages (Tg:Mpeg1) [125] combined with xenotransplanted labelled tumor cells enables the real-time monitorization of tumor induced angiogenesis and tumor behavior, as well the observation of the tumor and host innate immune interactions [111,126].