STAT3, VEGF, and PSMA Expression Patterns in Malignant Peripheral Nerve Sheath Tumors, Malignant Melanomas, and Glioblastomas: Does Staining Percentage and Intensity Have an Effect on Survival?

Malignant peripheral nerve sheath tumors (MPNSTs), glioblastomas (GBMs), and malignant melanomas (MMs) are neural crest-originating aggressive tumors with a poor prognosis. Signal transducer and transcription activator 3 (STAT3) plays a role in many biological processes, including cell life and proliferation, the acute phase response, chronic inflammation, autoimmunity, metabolism, and cancer progression, It is also known to be a prooncogenic transcription factor. Vascular endothelial growth factor (VEGF) is one of the most potent proangiogenic stimuli ever identified. It mediates tumor neovascularization, and is associated with angiogenesis and lymphangiogenesis. The prostate-specific membrane antigen (PSMA) folate hydrolase I, despite its name, has been found in tissues other than the prostate. It is overexpressed in prostate cancer cells and several other cancers, and has the potential to be a target for radioligand therapy. We investigated the value of STAT3, VEGF and PSMA immunohistochemical expression patterns and their effects on survival in MPNSTs, GBMs, and MMs. Their expression patterns were evaluated in 25 MPNSTs, 27 GBMs, and 25 MM cases. All GBM cases stained positively for STAT3 and VEGF. In the other groups, the staining patterns were heterogeneous. None of the cases showed positive staining with PSMA. There was no statistically significant difference in survival between cases with differing VEGF and STAT3 staining patterns in the MPSNT and MM groups, but there was an increase in mortality as the VEGF score increased in the GBM group. The suppression of VEGF and STAT3 may be a promising avenue for treatment of MPNSTs, GBMs, and MMs, although further research is needed.