Prostate-Specific Membrane Antigen (PSMA) Expression in The Neovasculature of High Grade Gliomas (Histopathological and Immunohistochemical Study)

Prostate-specific membrane antigen (PSMA) was first noticed in prostate cancer cells, thereafter, It has been found in the endothelial cells of neovasculature in a variety of tumors, but not in normal vascular endothelium, This specificity makes PSMA an ideal molecule for vascular targeting in Cancer theranostics (i.e., combined diagnostic and therapeutic). The objective of this study was to evaluate the immunohistochemical (IHC) expression of PSMA in the neovasculature (identified by CD 31) of high-grade gliomas (HGGs) and to Correlate PSMA IHC expression in HGGs with clinicopathological features, to detect its possible role in tumor angiogenesis, where PSMA can be used as a future diagnostic and therapeutic target. This retrospective study included a total of 69 archived, formalin-fixed, paraffin-embedded tissue blocks of HGGs, including 52 cases classified as WHO grade IV (75.4%) and 17 cases as WHO grade III (24.6%). The samples were immunohistochemically analyzed for PSMA expression (in both TMV and parenchymal tumor cells) which was assessed using the composite PSMA immunostaining score. A score (0) was considered negative while scores 1-7 were considered positive (1-4, 5-6, or 7; weak, moderate, or strong respectively). PSMA is expressed specifically and significantly in endothelial cells of tumor microvessels (TMV) of HGGs, A statistically significant relationship was detected between PSMA IHC expression in both TMV and in parenchymal tumor cells (TC) and various glioma subtypes (P-value < 0.05 and