The Importance of Prostate-Specific Membrane Antigen Expression in Carotid Body Paragangliomas

Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed in prostate cancer. It is, however, also expressed in the neovasculature of some non-prostatic solid tumors. Carotid body paragangliomas (CBPs) are highly vascular neoplasms. In this study, we aimed to investigate the possible role of PSMA expression in CBPs. There are no studies in the literature that report to have investigated the relationship between PSMA and CBPs.

This study is a retrospective analysis of cases diagnosed with CBP based on their demographic, clinical, radiological, surgical and immunohistochemical findings. Immunohistochemical examination results of Ki-67, S100, synaptophysin, chromogranin were retrieved from patient files. Then, the paraffin blocks of CBPs specimens, stained by PSMA-antibody by immunohistochemical methods were examined histopathologically.

The number of patients operated on for CBP was 12 (four men and eight women). Ten out of 12 specimens were suitable for staining and histopathological examination. Capsular and/or vascular invasions of tumors were seen in complicated cases. Intratumoral vascular PSMA expression was seen in all specimens except one. Extratumoral vascular PSMA expression was not detected in any of the cases. Tumoral cell PSMA staining was seen in six of ten cases.

We found higher intratumoral vascular expressions of PSMA nearly in all CBPs, but we could not assess the statistical significance because of the small number of specimens. These data might be a guide for future studies that are planned for either diagnostic or therapeutic approaches to CBPs.