TUG1 and osteosarcoma: Their high expression predicted poor prognosis of osteosarcoma (MALAT1 (HR = 2.15, 95%CI: 1.67–2.76, P < 0.001), TUG1 ((HR = 2.41, 95%CI: 1.42–4.07, P = 0.001), XIST (HR = 1.79, 95%CI: 1.40–2.30, P < 0.001), NEAT1 (HR = 1.96, 95%CI: 1.05–3.68, P = 0.035)).