IL6 and neoplasm: A variety of cytokines produced by tumour cells can induce the proliferation of myeloid‐derived suppressor cells (MDSCs), such as COX‐2, IL‐6 and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and VEGF can further enhance the immunosuppression of myeloid suppressor cells and enhance immune escape together.126, 127