Tumor necrosis factor-α (TNF-α) has also been reported to promote differentiation of osteoclasts from osteoclast precursors derived from bone marrow cells in vitro.5, 6, 7 TNF-α-induced osteoclast formation can be central to osteoerosive disorders such as rheumatoid arthritis, postmenopausal osteoporosis, periprosthetic bone loss, and periodontal disease.8, 9, 10, 11. This evidence concerns the gene TNF and postmenopausal osteoporosis.