Specifically, a group of 40 well-defined genes, classified according to their function, were able to distinguish between 2 different GBM signatures (Figure 7) revealing the possible different proliferative potential in high grade GBM tumours (VIM, GLUL, PLK1, HUWE1, RPS4X...)(Figure 8 and Table 4). The gene discussed is PLK1; the disease is glioblastoma.