Low expression of pentraxin 3 and nuclear factor-like 2 implying a relatively longer overall survival time in gliomas

Pentraxin 3 (PTX3) and nuclear factor-like 2 (Nrf2) are known to induce tumor progression in certain malignancies but act as tumor suppressors in other human neoplasms. In this study, we not only tested the association between PTX3 expression and the World Health Organization (WHO) tumor grading system but also evaluated overall patient survival under variable expression of PTX3 and Nrf2 in primary brain tumors (PBTs). Immunohistochemistry (IHC) was performed for PTX3 and Nrf2 in 10 nonneoplastic brain tissues and 197 PBTs. IHC scores were calculated as the degree of cytoplasmic and nuclear PTX3 and Nrf2 staining intensity multiplied by the percentage of positively stained tissue area. The correlation between PTX3 and Nrf2 IHC scores and tumor grades as well as overall survival time was analyzed by Pearson product-moment correlation and Kaplan-Meier estimate. According to our results, PTX3 IHC scores showed a positive correlation with the WHO grades of gliomas and meningiomas. In addition, we also observed that higher PTX3 expression was associated with poor prognosis in gliomas but not in meningiomas. The concordance between PTX3 and Nrf2 immunohistochemistry (IHC) scores was analyzed using linear regression analysis. When compared to groups with high IHC scores for either one or both biomarkers, gliomas with low expression of both PTX3 and Nrf2 showed significantly better prognosis. In conclusion, we demonstrated that high PTX3 expression implied aggressive tumor behavior and shorter survival time in glioma patients. In addition, our results also showed that gliomas with low PTX3 and Nrf2 immunohistochemical expression could imply a longer overall survival time. Therefore, the combination of lower PTX3 and Nrf2 immunohistochemical expression may be important in offering a better prognosis in gliomas, although the detailed mechanism is yet to be elucidated.