The RT-qPCR results indicated that the mRNA level of HIPK2 showed different degrees of reduction in osteosarcoma cells, as its expression was the lowest in Saos2 cells (0.3-fold vs control), followed by MG63 (0.4-fold vs control) and U2OS (0.4-fold vs control), and then HOS (0.55-fold vs control), 143B (0.55-fold vs control), T1-73 (0.6-fold vs control) and DAN (0.7-fold vs control) (Figure 1A). The gene discussed is HIPK2; the disease is osteosarcoma.