TNFSF11 and osteoporosis: Recent studies have elucidated that intracellular ROS (reactive oxygen species) is involved in the processing of osteoclast formation, and high level of ROS was found in osteoclast precursors when stimulated by RANKL.17, 40, 41 Other studies demonstrated that osteoporotic postmenopausal women had high oxidative stress index when compared to the healthy group,42 suggesting a high level of oxidative stress might contribute to the development of osteoporosis and suppressing oxidative stress would be a potential treatment for osteoporosis.