CXCR4 and neoplasm: For example, in a mouse model of brain metastases of breast cancer, CXCR4/TRAIL-enriched exosomes enhanced the anti-tumor efficacy of chemotherapy, while exosomes-based delivery of cPLA2 siRNA and metformin targeting intracranial xenografts of glioblastoma suppressed the energy metabolism of tumor cells and exerted cell growth inhibitory effects [11, 12].