PCNA and osteosarcoma: To further confirm the function of lncRNA-CIR in osteosarcoma cell proliferation, the MG63 and 143B cells were transfected with lncRNA-CIR silenced or overexpressed plasmids, and the expression of PCNA and Ki67 in MG63 (Fig. 2d, e) and 143B cells (Fig. 3d, e) was determined by Western blot analysis.