(II) PSMC2 plays pivotal roles in osteosarcoma cell proliferation, apoptosis, colony forming, migration, invasion and tumorigenesis; (III) In osteosarcoma cells, the expression of PSMC2 is modest and adequate for osteosarcoma malignant feature; (IV) PSMC2 mainly plays the carcinogenesis role in osteosarcoma by regulating cancer-related genes including ITGA6, FN1, CCND1, CCNE2 and TGFβR2. This evidence concerns the gene CCND1 and cancer.