E2F2 and osteosarcoma: As a tumor suppressor miRNA, let‐7a was found to be downregulated in osteosarcoma tissues than in the normal bone tissues,18 and let‐7a could suppress the cancer cell proliferation through inhibiting it's downstream oncogenes such as RAS, CCR7, E2F2, and CCDN2.7, 27, 28 Here, we show that let‐7a targets CBX2 as well and represses its expression.