All four TCGA GBM samples with the outlier NTRK1 expression showed elevated activity of the NGF/TrkA-downstream pathway (Figure 3B, Table S3), indicating that the NTRK1 fusion gene expression in these samples had the effects consistent with the NGF-triggered activation of the NGF/TrkA-downstream pathway. Here, NTRK1 is linked to glioblastoma.