One study found that irisin can suppress the migration, proliferation, and invasion of lung cancer cells in vivo[22]; on the contrary, other 2 studies found that irisin may promote the invasion and proliferation in human hepatocellular carcinoma.[23,24] Nonetheless, Moon and Mantzoros[25] found that irisin had no effect on cell proliferation and malignant potential in several cancer cell lines. Here, FNDC5 is linked to cancer.