IDH1 and glioma: Correlation analysis of PDPN with the clinical characteristics of glioma patients showed that the main variable PDPN was significantly negatively correlated with IDH mutation status, chr-1q-19-codeletion and MGMT-promoter-status (p < 0.001), while it was significantly positively correlated with tumor grade and age (p < 0.05) (Fig 3C).