Systemic administration of intact, bacterially derived minicells results in rapid accumulation of the minicells in the microenvironment of a brain tumor, in therapeutically significant concentrations, without requiring endothelial endocytosis/transcytosis across the blood brain barrier or any other mechanism by which, pursuant to conventional approaches, nanoparticles have entered into that microenvironment. Accordingly, a wide variety of brain tumors, both primary and metastatic, can be treated by administering systemically a therapeutically effective amount of a composition comprised of a plurality of such minicells, each minicell being a vehicle for an active agent against the tumor, such as a radionuclide, a functional nucleic acid or a plasmid encoding one, or a chemotherapeutic agent.完整的、細菌衍生的微細胞的全身性投藥在治療顯著的濃度下致使微細胞在一腦腫瘤的微環境中快速的累積，不需要穿過血腦障壁的內皮胞吞作用/胞吞轉送作用或藉由根據傳統的方法的任何其它機制，奈米粒子已進入至那微環境中。因此，各種不同的腦腫瘤，原發性與轉移性這兩者，可以藉由全身性投藥一治療有效量的一包含有複數個該等微細胞的組成物而被治療，各個微細胞是一用於對抗腫瘤的一活性劑的載劑，諸如放射核種、一功能性核酸或一編碼一功能性核酸的質體，或者一化學治療劑。
