STAT3 and inflammatory bowel disease: Recently, it has been suggested that iron may modulate Toll-like receptor 4 (TLR4) signaling and IL-6 production.[53] TLR4 expression is upregulated in IBD[54] and promotes inflammation-associated colorectal tumorigenesis in mice.[55] As both IL-6 and IL-11 activate Stat3, and in turn are regulated by Stat3 and/or NFκB,[35], [56] it is likely that iron and colonic inflammation may regulate IL-11 in a similar manner to IL-6.