Surprisingly, OPG reduced osteoclast numbers by only 27.7% ± 5.14% in the culture with mtMDA CM and 49.3% ± 14.10% in the culture with MDA CM (Fig. 1d), indicating that RANKL was not the sole factor responsible for the stimulatory effect of these cancer cells on osteoclastogenesis. The gene discussed is TNFSF11; the disease is cancer.