TLR4 and colitis: While Fusobacterium nucleatum can significantly up-regulate the expression of miR-21 through TLR4/MYD88/NF-κB pathway and facilitate the progression of colitis-associated colorectal cancer [102], in CRC patients on the other side, intestinal microbiota can also influence the host gene expression of intestinal microRNAs, which contributes to protecting intestinal homeostasis and attenuating gut inflammation [103,104].