This finding suggests that after the expression of PSA in SaOS-2 cells, SaOS-2 cells demonstrate not only enhanced osteogenic functions, but also strengthened capabilities to activate OCs and secondary osteolysis — this might have a subtle connection with the phenomenon that during early PCa bone metastasis, osteogenic responses are preceded by osteolytic processes which are produced by OB-activated OCs (5, 36). Here, KLK3 is linked to posterior cortical atrophy.