Neovascular prostate specific membrane antigen (PSMA) expression in bone and soft tissue sarcoma: a systematic...

Area of Science:

• Oncology
• Molecular Imaging
• Cancer Biology

Background:

• Bone and soft tissue sarcomas are rare, heterogeneous mesenchymal cancers with limited treatment options beyond surgery.
• Prostate-specific membrane antigen (PSMA) is a promising target for radioligand therapy, particularly in prostate cancer.
• Previous studies suggest PSMA expression in the neovasculature of soft tissue sarcomas and incidental uptake in hemangiomas.

Purpose of the Study:

• To systematically investigate prostate-specific membrane antigen (PSMA) expression in a wide range of bone and soft tissue tumors.
• To confirm and expand upon previous findings of PSMA expression in soft tissue sarcomas.
• To evaluate the potential of PSMA-targeted therapies for bone and soft tissue sarcomas.

Main Methods:

• Immunohistochemistry was employed to assess PSMA expression.
• A cohort of 706 diverse tumor samples, including bone sarcomas, soft tissue sarcomas, and vascular tumors, were analyzed.
• Tumor samples were scored for PSMA expression, with a focus on neovascular and tumor cell expression.

Main Results:

• High PSMA expression in tumor neovasculature was observed in 29% of soft tissue sarcomas and 33% of bone sarcomas.
• Malignant bone and soft tissue tumors, including rhabdomyosarcoma, mesenchymal chondrosarcoma, undifferentiated sarcoma, and osteosarcoma, frequently expressed PSMA.
• Giant cell tumor of bone also showed high PSMA labeling in 67% of cases. Non-neoplastic vessels in vascular tumors exhibited lower PSMA expression (0-40%).

Conclusions:

• A significant subset of bone and soft tissue tumors, encompassing both malignant and intermediate-grade types, express prostate-specific membrane antigen (PSMA).
• These findings support the potential utility of PSMA-targeted positron emission tomography/computed tomography (PET/CT) scans for diagnosis and staging.
• Patients with PSMA-expressing bone and soft tissue tumors may be candidates for novel PSMA-targeted radioligand therapies.