In detail, Bonfiglioli et al. found that a specific sequence motif (UUGU), characterizing some of the let-7 family members, determined the activation of an M1-like microglial phenotype, through the interaction with Toll-like receptor 7 (TLR7), which can trigger an anti-tumoral microenvironment at the periphery of the GBM cell mass: this is in agreement with the downregulation of let-7 miRNAs observed in GBM cells and with the correlation between their down expression and a poor prognosis in both human and murine GBM [79,80]. The gene discussed is TLR7; the disease is glioblastoma.