TLR4 and neoplasm: Xiao et al. further demonstrated that TLR4 signaling exerts significant influence in the regulation of B cells [135], as they reported that PD-1high B cells were significantly enriched in tumor tissues compared to blood, and expressed high levels of the immunosuppressive IL-10, TGF-β, and PD-L1, inhibiting the activation and proliferation of T-cells in vitro.