On the other side, GB-derived spheroids or gliomaspheres have been generated by the mechanical or enzymatic dissociation of tumor specimens into a single cell suspension followed by growth in absence of serum and in the presence of supplements, such as B27 and N2 nutrient mix, epidermal growth factor (EGF) and/or basic fibroblast growth factor (bFGF), to positively select for GSCs [78,80]. Here, EGF is linked to neoplasm.