Prostate-specific membrane antigen: a new potential prognostic marker of osteosarcoma.

Previous studies have demonstrated that the expression of prostate-specific membrane antigen (PSMA) is restricted to endothelium from tumor-associated neovasculature. But the expression of PSMA in osteosarcoma and its clinical significance are unknown. Using immunohistochemical analysis and quantum dot probes, we found that 46.7% (21/45) of the osteosarcoma showed positive staining for PSMA while no PSMA staining in osteofibrous dysplasia. The expression and localization of PSMA was confirmed by CD34 staining. More importantly, the expression of PSMA is correlated with tumor size, pulmonary metastasis and worse survival (survival rate 63.2% in the PSMA-negative group versus 36.6% in the PSMA-positive group). Thus, PSMA could be used as an independent prognostic marker for the osteosarcoma patients, and PSMA staining in tumor-associated neovasculature may be a potential target for antineovasculature-based therapy in osteosarcoma.