KLK4 and glioblastoma: GSEA of concordant genes confirmed epigenetic regulation of pathways known to be contributing to glioblastoma pathogenesis such as transcription factors RUNX [46], SMADs [21, 47] and PPARA [48], neddylation of protein [49], homeostasis disorder including Basigin [50] and Kallikrein/kinin complex [51].