TLR4 and familial pancreatic carcinoma: Compared with normal pancreatic tissue, miR-203 overexpressed by pancreatic cancer cells can be transferred to dendritic cells via exosomes, resulting in dendritic cell dysfunction via downregulation of Toll-like receptor 4 (TLR4) expression and its downstream genes, such as tumor necrosis factor alpha (TNF-α) and interleukin 12 (IL-12) (Zhou et al., 2014a).