To further ascertain the believability of the IRGP signature in normal human astrocytes and low-grade glioma cells (WHO Grade III, astrocytoma), we performed western blotting analysis and qRT-PCR to investigate the transcription and protein expression levels of four selected IRGs (EGFR, SLIT1, ADRB2, and MSR1) in these cell lines. The gene discussed is EGFR; the disease is astrocytoma (excluding glioblastoma).