It is possible that in vitro experiments have used high doses of EGF and are more reminiscent of situations where cancer cells with high expression levels of EGF-like ligands result in osteolytic lesions in bone.(10,35) Under physiological conditions, the expression of EGF-like ligands in bone may be low, and therefore, activating osteoblastic EGFR activity actually decreases osteoclast formation and bone resorption. The gene discussed is EGF; the disease is cancer.