Initially, they resist metastasis by producing plasminogen activators, but tumor‐secreted serpins neutralize this response, supporting tumor survival.[85] Zhang et al.[86] showed that astrocyte‐derived exosomes containing miR‐19A downregulate PTEN in tumor cells, increasing CCL2 expression and recruiting peripheral myeloid cells, thereby supporting tumor growth in the brain. The gene discussed is CCL2; the disease is neoplasm.