The GDS2853 gene expression profile revealed that the signal strength of the signature gene ERBB4 (Fig. 3a), but not Olig2 (Fig. 3b), was significantly different between low-grade and high-grade astrocytomas; PLCβ1 data analysis agrees with ERBB4 in separating low-grade (n = 8) and high-grade (n = 6) tumors (Fig. 3c; p = 4.0E-4). The gene discussed is OLIG2; the disease is astrocytoma (excluding glioblastoma).