FNDC5 and cancer: Other studies showed a role of irisin in suppressing other hallmarks of cancer such as “sustaining proliferative signaling” [36] by targeting the PI3K/Akt pathway [16] or “evading growth suppressors” [36] via targeting the AMPK-mTOR pathway [20] or “activating invasion and metastasis” [36] by decreasing cell migration and inhibiting the epithelial-mesenchymal transition [18].