HOXD13 and glioblastoma: Among the 15 genes analyzed for expression levels using qPCR (Figures 2–4, Figure S1), only three—CD44, TNFSF14, and HOXD13—were found to be overexpressed in GBM compared to both LGG and normal brain tissue, as shown in Figures 2D, 3D, and 4D.