Although pro-angiogenic and cancer cell bone-homing properties of βAR stimulation in the osteoblast lineage are mainly relevant to the early establishment of circulating breast cancer cells in the bone marrow environment, RANKL and IL-6 are, before all, two well-known potent osteoclastogenic cytokines [158,189,190,191]. The gene discussed is ADRB2; the disease is breast cancer.