MiR-21-5p and miR-214-5p are also thought to act on microglia, with the former promoting M1 polarization and releasing INOS from microglia, and the latter being encapsulated by GBM-derived exosomes that act directly and inhibit the activation of microglia by suppressing the relative expression of CXCL5 at the transcript and protein levels in microglia, both promoting IL-6, IL-8, Tumor necrosis factor-α(TNF -α) and other pro-inflammatory substances (Yang et al., 2019; Yin et al., 2020). The gene discussed is TNF; the disease is glioblastoma.