Table 4.

Multivariate analysis of prognostic factors

	Overall survival
	HR	95%CI	P value
Differentiation	0.653	0.373-1.144	0.136
Tumor size	1.315	0.859-2.012	0.208
TNM stage	0.920	0.529-1.601	0.768
Lymphatic metastasis	2.499	1.345-4.641	0.004
HIF-1α	1.802	0.9.0-3.489	0.081
Sema4D	0.780	0.402-1.513	0.462
	2.147	1.157-3.983	0.015

HIF-1α: Hypoxia-inducible factor-1 alpha; Sema4D: Semaphorin 4D.