Interleukin 11 (IL-11) is a pleiotropic cytokine with effects on various tissues including the bone marrow, brain, and intestinal mucosa (Du & Williams). It belongs to the IL-6 family of cytokines that share a common signal transducer, gp130. Culture of mouse bone marrow cells with IL-11 in combination with IL-3, IL-6, and stem cell factor induces significant expansion and proliferation of colony-forming cells in vitro (Peters et al.). In addition, in combination with IL-3, IL-11 significantly enhances the growth of megakaryocytic colonies in vitro, suggesting its role in augmenting mouse megakaryopoiesis (Yonemura et al.). IL-11 is expressed in a wide range of normal adult mouse tissues, including the central nervous system, thymus, lung, and bone. The mouse IL-11 cDNA was cloned using an expression library generated from the lipopolysaccharide-induced mouse fetal thymic cell line, T2 (Morris et al.). The binding of IL-11 to its receptor induces heterodimerization with the gp130 subunit and activation of JAK tyrosine kinases. IL-11 also plays a role in cancer progression by inducing the proliferation of epithelial cancer cells and the survival of metastatic cells at distant organs. Recently, IL-11 has gained interest for its role in the pathogenesis of diseases in dysregulated mucosal homeostasis associated with STAT3 upregulation, including gastrointestinal cancers (Putoczki et al.).