COL18A1 and metastatic neoplasm: Furthermore, six of the proteins we identified as upregulated in the OS EV proteome were previously found to associate with metastatic disease, recurrence/disease free interval, or overall survival in human OS, these include: RPS3 [77], RPS9 [78], VCP [79], BUB3 [80], PHGDH [81] and endostatin, which is one of the two cleavage products of Col18A1 [82].