First, to find the IGF-1-associated differentially expressed genes (DEGs) from GBM microarray data of TCGA (n = 528), patients were selected and subdivided into two groups, IGF-1 upregulation (with an IGF-1 z score of >0.5, n = 115) and IGF-1 downregulation (with an IGF-1 z score of <−0.5, n = 197), using the cBio Cancer Genomics Portal (cBioPortal)16. Here, IGF1 is linked to cancer.