MIF and neoplasm: First identified in the 1960s as a macrophage migration inhibitor, MIF is an upstream immunoregulatory cytokine that contributes to tumorigenesis through its interactions with antigen-presenting cells and cytotoxic T lymphocytes in the tumor microenvironment (TME), and has been studied as a mediator of autoimmune diseases, such as rheumatoid arthritis [10–14].