Fig. 4

The co-expression of EGFR and NTN4 contribute to TMZ resistance in GBM patients. Clinical information and gene expression data of totally 92 TMZ-treated GBM patients were extracted from the TCGA-glioblastoma dataset. To describe the contribution of EGFR and NTN4 to survival time of TMZ-treated patients, we used both 3D axes surface plots and Kaplan-Meier analysis. In 3D axes surface plots, the X and Y axes represent the expression of EGFR and NTN4, respectively. The Z axis represents survival time of each patient. Here, we selected the 20% of patients (top 19 patients) with either the highest (right side of red line) or lowest (left side of green line) expression of target genes and compared the survival time. a High EGFR expression slightly but not significantly predicts poor patient survival. b The expression of NTN4 itself does not correlate with patient survival. c Weighted high expression of EGFR and NTN4 significantly predicts poor patient survival. d NTN1 was used as a control in this study. Neither single NTN1 expression nor weighted expression of EGFR and NTN1 correlated with patient survival. e Violin plot representing the relationship between all different combinations of EGFR/NTN4/NTN1 expression and survival time of TMZ-treated GBM patients. Dark grey bar-box indicates a significant p-value (< 0.05). Only when both EGFR and NTN4 were highly expressed in patients, were survival times lowest in TMZ-treated patients