M1-like microglia/macrophage-derived nitric oxide (NO, which is the product of iNOS activation) and activated-NK cells can both cause induction of p53 in tumor cells, which could lead to this observed caspase3-mediated apoptosis in the CD68high GBM tumor cells to cause tumor shrinkage [52,53,54]. The gene discussed is TP53; the disease is glioblastoma.