LIF and neoplasm: (v) indirect cross-talk via chemokines (interleukin 6, IL-6), TGF-β, insulin-like growth factor 1 (IGF-1), monocyte chemotactic protein 4 (MCP-4), interleukin 19 (IL-19), VEGF and leukemia inhibitory factor (LIF), promoting tumor cell invasion [123,124];