Table 2. Summary of metabolites statistical data from healthy controls (CTRL) and ESCC groups.

The Variable importance in projection (VIP) values more than 1,000 were used for the statistical significance. Univariate statistical significance of p < 0.05 was identified to distinguish early ESCC metabolites from CTRL. Sensitivity, specificity, AUC curve value of the metabolites were also for discrimination ESCC from CTRL. Metabolites in bold showed potential biomarkers between ESCC and CTRL.

Metabolites	ESCC vs CTRL
	VIP	p	trend	sensitivity	specificity	AUC
1-Methylhistidine	1.096	2.55 × 10−8	↓	0.694	0.783	0.754
3-Hydroxybutyrate	2.430	2.27 × 10−13	↑	0.712	0.754	0.712
Acetate	2.171	8.09 × 10−6	↑	0.649	0.525	0.637
Acetone	2.143	0.0005	↑	0.432	0.708	0.584
Alanine	2.516	0.0004	↓	0.753	0.822	0.789
Choline	3.819	2. 27 ×10−21	↑	0.839	0.876	0.855
Citrate	1.134	0.031	↑	0.587	0.682	0.633
Creatinine	1.023	2.66 × 10−7	↑	0.691	0.535	0.579
Dihydrothymine	3.055	3.25 × 10−21	↓	0.845	0.822	0.824
Glutamate	3.587	1.38 × 10−10	↑	0.823	0.847	0.834
Glutamine	3.135	1.43 × 10−8	↑	0.803	0.841	0.816
Glycerol	1.725	2.68 × 10−5	↑	0.662	0.713	0.678
Isobutyrate	1.543	1.54 × 10−5	↑	0.630	0.512	0.594
Isoleucine	1.891	6.73 × 10−16	↓	0.610	0.675	0.625
Isopropanol	1.938	0.0007	↓	0.723	0.641	0.662
Leucine	1.964	1.38 × 10−11	↓	0.749	0.810	0.786
Low density lipoprotein	2.061	0.017	↑	0.520	0.812	0.642
Lysine	2.406	7.83 × 10−6	↑	0.707	0.556	0.634
Malonate	1.191	2.48 × 10−7	↑	0.498	0.674	0.589
Methanol	2.273	1.36 × 10−8	↓	0.476	0.683	0.529
Methionine	1.378	1.96 × 10−5	↓	0.588	0.786	0.671
Methylguanidine	2.648	1.64 × 10−10	↓	0.801	0.721	0.742
myo-Inositol	1.573	0.003	↓	0.719	0.843	0.785/
Pyruvate	2.054	1.84 × 10−9	↓	0.723	0.810	0.773
Trimethylamine N-oxide	1.128	6.45 × 10−6	↓	0.675	0.497	0.576
Valine	2.964	6.45 × 10−9	↓	0.801	0.843	0.827
Very low density lipoprotein	2.234	0.014	↓	0.611	0.720	0.651
α-Glucose	4.672	3.05 × 10−9	↓	0.891	0.856	0.879
β-Glucose	3.656	0.0003	↓	0.853	0.769	0.798

Notes.

‘ ↑’, increased. ‘ ↓’, decreased.