Fig. 4

Histologic images of brain metastatic tumor cells. a Paraffin-embedded section of the brain of a control mouse showing the formation of metastatic brain lesions derived from eGFP expressing breast cancer cells. b Macrophages loaded with red fluorescent nanospheres infiltrating the brain metastases detected by immunofluorescent staining using anti-human CD68 antibodies labeled with APEX Pacific Blue fluorochrome. Green fluorescence is emitted by the brain metastatic tumor cells. Red fluorescence and blue fluorescence result from the red fluorescent nanospheres included within the macrophages and the macrophage staining, respectively