LIF and cancer: LIF, a pleiotropic cytokine that belongs to the Interleukin (IL)-6 family [14], is overexpressed in a variety of solid tumours, including pancreas [15], stomach [16], liver [17], colon [18] and breast [19], and promotes cancer cell proliferation, remodelling, invasiveness and epithelial-to-mesenchymal transition (EMT) [20].