Figure 4. (A, B) Comparison of the expression levels of PDIs and clinical features between two subgroups (cluster 1 vs cluster 2). Principal component analysis (PCA) was performed to reveal the difference of PDIs mRNA expression between two clusters in TCGA (C) and CGGA (D). The prognostic value of clusters in glioma patients. Kaplan–Meier survival analyses were used to demonstrate differences in OS, PFI and DSS between the two clusters of LGGGBM samples from TCGA (E–G) and CGGA (H). TCGA database as training set and CGGA database as the validation set.