4.

Univariate and multivariate analysis of clinicopathological parameters associated with overall survival in osteosarcoma patients

Variables	Univariate analysis			Multivariate analysis
	HR (95% CI)	P		HR (95% CI)	P
HR, hazard ratio; 95% CI, 95% confident interval; BMPR2, bone morphogenetic protein receptor 2; HIF1-α, hypoxia-inducible factor 1-α.
Gender (male vs. female)	1.108 (0.634–1.935)	0.719
Age (≤20 vs. >20 years)	0.777 (0.445–1.359)	0.377
Tumor location	0.886 (0.690–1.139)	0.347
Histological classification	1.298 (0.908–1.855)	0.153
Tumor grade (I vs. II+III)	2.441 (1.274–4.676)	0.007		2.276 (1.197–4.328)	0.012
BMPR2 (positive vs. negative)	1.965 (0.958–4.031)	0.046		2.053 (1.011–4.171)	0.037
HIF1-α (positive vs. negative)	3.664 (1.917–7.004)	<0.001		3.287 (1.735–6.229)	<0.001