TNFRSF11A and Hypocalcemia: However, both denosumab and bisphosphonates are burdened by side effects like jaw osteonecrosis, hypocalcemia, urinary tract infections, dermatitis, hypercholesterolemia, and atypical fractures [87, 100]; moreover, RANK, as shown in this article, is not the only pivotal factor in the bone metastatic process; thus, molecular biology and transcriptomic analysis may be crucial in defining new molecular targets other than the RANK/RANKL/OPG pathway, optimizing bone metastases treatment [65, 66].