SERPINA3 and prostate cancer: In a co‐culture of osteoblasts (OBs) and BPCa cells, SERPINA3 and LCN2 were remarkably upregulated in BPCa via OB‐derived extracellular vesicles, while they were not in the co‐culture of OBs and osteolytic prostate cancer (LPCa) cells.