TLR3 and cancer: HIV-infected J1.1 cell exosomes and synthetic HIV TAR RNA induced significant expression of TLR3-responsive ISGs IFIT1 and IFNB1 in SCC9 and HSC3 cells (Fig. 3f, g), suggesting that TAR RNA-bearing exosomes from HIV-1-infected T cells would signal through TLR3 in cancer cells.