To examine the spatial localisation and tumour specificity of glycosylated αDG (hereafter stated as αDG for simplicity), we first examined a variant of GBM, gliosarcoma (GS), which undergoes a partial process of de-differentiation with secondary loss of the glial differentiation marker GFAP and acquisition of mesenchymal characteristics, a process similar to epithelial–mesenchymal transition (EMT) [45]. Here, GFAP is linked to Gerstmann syndrome.