Figures 11, 12, 13 demonstrate the infiltration of the parotid gland by metastatic GBM, as shown by hematoxylin and eosin (H&E) staining (Figure 11), glial fibrillary acidic protein (GFAP) staining (Figure 12), and oligodendrocyte transcription factor 2 (Olig2) staining (Figure 13). The gene discussed is OLIG2; the disease is glioblastoma.