Further, the immunochemical staining of Ki67 in the tumor sections revealed that circRNA-CIRH1A silencing reduced the cells stained with Ki-67 (Fig. 3C, p < 0.001), which suggest that a high level of circRNA-CIRH1A expression is required for the sustained proliferation of U2OS cells in vivo. The gene discussed is UTP4; the disease is neoplasm.