TLR8 and glioblastoma: Synthetic siRNA duplexes have now been show to activate PKR in glioblastoma cells [17], RIG-I in glioblastoma cells and primary human monocytes [7,18], TLR3 in HEK293 cells and murine models [19,20], TLR7 in murine leukocytes and human plasmacytoid dendritic cells [21], and TLR8 in human monocytes [22].