The results of the RT-qPCR assay showed that the mRNA expression level of HOXA9 in osteosarcoma tissues was significantly higher than that of normal tissue, and the mRNA expression level of HOXA9 in osteosarcoma cell lines was significantly higher than that of normal osteoblasts (Figures 3(d) and 3(e)). Here, HOXA9 is linked to osteosarcoma.