Since SIRT2 is highly expressed in osteosarcoma cell lines MG63 and Saos-2, two small interfering RNAs (siRNAs) of SIRT2, Si-SIRT2-1 (abbreviated as Si-1) and Si-SIRT2-2 (abbreviated as Si-2) were used to transfect MG63 and Saos-2 cells respectively (Fig. 2A). This evidence concerns the gene SIRT2 and osteosarcoma.