TLR4 and cancer: Youn et al. [39] showed that pancreatic adenocarcinoma up-regulated factor (PAUF), a tumor-promoting protein secreted by cancer cells that acts on the TLR4 receptor on the surface of immune cells, induces human pancreatic cancer cell migration via the TLR4/MyD88/NF-κB signaling pathway rather than the TLR4/interleukin-1 receptor domain-containing adapter protein signaling pathway.