Table 5. HIF-1α and HIF-2α expression and clinicopathological features for colorectal cancer.

					Heterogeneity
Clinicopathological features	Nuber of studies	Nuber of patients	Pooled OR (95%CI)	P value	I2(%)	P value	Model used
HIF-1α
Differentiation grade	15	2226	0.97 (0.67–1.39)	0.864	39.2	0.06	REM
Dukes' stages	5	408	0.39(0.17–0.89)	0.025	66.2	0.019	REM
Lymphnode status	15	1490	0.49(0.32–0.73)	0.001	62.4	0.001	REM
Metastasis	5	480	0.29(0.11–0.81)	0.018	52.8	0.076	REM
UICC stage	9	1733	0.42(0.3–0.59)	0.000	53.2	0.029	REM
Depth of invasion	9	1016	0.71(0.51–0.99)	0.045	0.00	0.851	FEM
HIF-2α
Differentiation grade	2	782	0.484(0.289–0.812)	0.006	58	0.123	FEM
Dukes' stages	2	177	0.9(0.197–4.168)	0.9	82	0.019	REM
Lymphnode status	3	329	0.95(0.418–2.16)	0.904	63.7	0.064	REM
Depth of invasion	2	177	0.379(0.038–3.798)	0.409	83.4	0.014	REM

REM, random-effects model; FEM, fixed-effects model; OR, odds ratio; CI, confidence interval.