The post-hoc multiple comparison revealed that the RANKL/OPG ratio in GCT was significantly greater than that of chondrosarcoma (P < 0.001), osteosarcoma (P < 0.001), osteochondroma (P = 0.002), fibrous dysplasia (P = 0.002), enchondroma (P = 0.001), Ewing’s sarcoma (P = 0.017) and ABC (P = 0.021). This evidence concerns the gene TNFSF11 and osteosarcoma.