Table 2. Univariate and multivariate Cox regression analysis of HDAC4 and survival in patients with ESCC.

	Univariate analysis			Multivariate analysis
Variables	HR	95% CI	P value	HR	95% CI	P value
Overall Survival
Gender (Female vs male)	1.034	0.515-2.077	0.925
Age (≥60y vs <60y)	1.558	0.880-2.758	0.129
Tobacco use (yes vs no)	1.068	0.591-1.931	0.827
Alcohol use (yes vs no)	1.207	0.681-2.139	0.520
Tumor location(upper and middle vs lower)	1.494	0.801-2.789	0.207
Tumor length (≥5cm vs <5cm)	1.503	0.835-2.707	0.174
Pathological grade (III vs I-II)	1.646	0.881-3.074	0.118
T stage (III-IV vs I-II)	1.826	0.819-4.072	0.141
N stage (N1-3 vs N0)	3.056	1.628-5.737	0.001	1.443	0.548-3.803	0.458
TNM stage (III vs I-II)	3.264	1.780-5.985	0.000	2.359	1.253-4.443	0.008
HDAC4 expression (high vs low)	3.740	1.969-7.104	0.000	2.846	1.456-5.566	0.002
Progression-Free Survival
Gender (Female vs male)	0.549	0.215-1.399	0.209
Age (≥60y vs <60y)	0.650	0.344-1.228	0.185
Tobacco use (yes vs no)	1.536	0.769-3.067	0.224
Alcohol use (yes vs no)	1.018	0.546-1.895	0.956
Tumor location(upper and middle vs lower)	0.745	0.344-1.614	0.455
Tumor length (≥5cm vs <5cm)	1.235	0.645-2.364	0.525
Pathological grade (III vs I-II)	1.273	0.605-2.678	0.508
T stage (III-IV vs I-II)	1.331	0.614-2.886	0.469
N stage (N1-3 vs N0)	2.670	1.387-5.141	0.003	3.414	1.201-9.708	0.021
TNM stage (III vs I-II)	2.026	1.086-3.781	0.027	0.703	0.261-1.892	0.486
HDAC4 expression (high vs low)	1.762	0.941-3.297	0.077	1.331	0.682-2.597	0.402

NOTE: The bold digit represents P value smaller than 0.05. ESCC, esophageal squamous cell carcinoma; TNM, tumor node metastasis. HR, hazard ratio; CI, confidence interval.