While searching the role of irisin in cancer, malignant breast epithelial cells (MCF-7), human non-malignant breast epithelial cells (MCF-10a), and malignant aggressive breast epithelial cells (MDA-MB-231) were used for a study, and it was found that the number of malignant breast tumor cells decreased significantly upon exposure to irisin [69]. Here, FNDC5 is linked to cancer.