In breast cancer, several studies have implicated MIF in the promotion of malignancy: elevated MIF levels have been found in the tissue sections [39,40,41] and sera of breast cancer patients when compared to healthy individuals [40]; MIF has been shown to have an important role in the promotion of cellular proliferation and invasion in vitro [39]; and it has also been shown to have an anti-tumoral immunosuppressive role in vivo [28]. Here, MIF is linked to breast cancer.