HIF1A and bone neoplasm: Our results indicated that HIF-1α overexpression was significantly associated with differentiation (RR = 1.56, 95% CI 1.00–2.43, P = 0.049), clinical stage (RR = 1.75, 95% CI 1.25–2.45, P = 0.001), metastasis (RR = 1.78, 95% CI 1.58–2.00, P <  0.001), and microvessel density (SMD = 2.34, 95% CI 1.35–3.34, P <  0.001) of bone tumor.