The signaling pathway of the receptor activator of nuclear factor-kB (RANK) and its ligand (RANKL) has a crucial role in several physiological processes, namely, bone remodeling, mammary gland development and functional activation of immune cells; it also plays an important role in breast tumorigenesis, BC progression and therapy resistance, as recently reviewed by us [205]. Here, TNFSF11 is linked to breast cancer.