Table 3.

Levels of the most discriminative metabolites (VIP >3) for RCC subtype classification.

Name	m/z	Mode	VIP	Peak intensity			Ratio			Peak Intensity	Ratio
				Mean cc	Mean pap	Mean chro	pap/cc	chro/cc	pap/chro	Mean Healthy	RCC/Healthy
Creatine	132.07694	POS	10.51	2.98E + 09	1.31E + 09	4.92E + 09	0.44	1.65	0.27*	2.06E + 09	1.26
L-Acetylcarnitine	204.12320	POS	10.43	4.50E + 09	1.91E + 09	3.13E + 09	0.42**	0.7	0.61	2.90E + 09	1.24
L-Carnitine	162.11262	POS	6.85	2.18E + 09	1.03E + 09	1.79E + 09	0.47*	0.82	0.58	1.34E + 09	1.82
L-Proline	116.07095	POS	6.45	1.39E + 09	2.06E + 09	8.66E + 08	1.48*	0.62	2.38***	1.56E + 09	0.71*
L-Phenylalanine	166.08636	POS	6.07	1.44E + 09	2.07E + 09	1.09E + 09	1.43	0.76	1.90*	2.09E + 09	0.51*
Betaine	118.08658	POS	5.15	2.10E + 09	2.46E + 09	1.82E + 09	1.17	0.87	1.35	1.71E + 09	1.44
Hypoxanthine	137.04591	POS	5.11	1.21E + 09	1.95E + 09	1.79E + 09	1.61*	1.48	1.09	3.26E + 09	0.54**
L-Lactic acid	89.02295	NEG	5	3.45E + 09	3.87E + 09	3.55E + 09	1.12	1.03	1.09	2.16E + 06	0.8
L-Isoleucine	132.10212	POS	4.65	1.44E + 09	1.51E + 09	8.21E + 08	1.05	0.57	1.83*	1.26E + 09	0.56**
Glycerophosphocholine	296.06608	POS	4.03	4.80E + 08	5.79E + 08	8.33E + 08	1.21	1.73	0.7	2.86E + 08	2.06
L-Methionine	150.05848	POS	3.89	2.18E + 08	6.83E + 08	2.83E + 08	3.14**	1.3	2.41*	6.15E + 08	0.36**
L-Tyrosine	182.08135	POS	3.7	3.99E + 08	7.36E + 08	3.26E + 08	1.85**	0.82	2.26***	9.71E + 08	0.49*
L-Palmitoylcarnitine	400.34272	POS	3.66	4.48E + 08	1.05E + 08	1.84E + 08	0.23**	0.41	0.57	1.17E + 08	0.96
Dimethylglycine	104.07109	POS	3.63	4.50E + 08	3.42E + 08	3.94E + 07	0.76	0.09***	8.67*	1.28E + 08	1.01
L-Tryptophan	205.09736	POS	3.4	4.34E + 08	6.37E + 08	2.85E + 08	1.47	0.66	2.24*	7.77E + 08	0.41**
Hydroxybutyrylcarnitine	248.14922	POS	3.22	4.08E + 08	1.22E + 08	5.12E + 08	0.3	1.26	0.24	2.50E + 08	2.62*
N-Acetyl-L-aspartic acid	174.03976	NEG	3.21	3.81E + 07	8.15E + 07	3.57E + 08	2.14	9.37**	0.23*	5.97E + 08	0.29*
Adenosine	268.10419	POS	3.19	1.19E + 08	1.09E + 08	4.88E + 08	0.91	4.1	0.22	1.45E + 08	1.37
L-Malic acid	133.01299	NEG	3.19	4.93E + 08	2.53E + 08	2.23E + 08	0.51	0.45*	1.14	5.19E + 08	0.63
Isobutyryl-L-carnitine	232.15447	POS	3.14	4.66E + 08	3.39E + 08	6.25E + 08	0.73	1.34	0.54	4.82E + 08	1.39
L-Glutamic acid	148.06055	POS	3.07	1.09E + 09	7.98E + 08	5.56E + 08	0.73	0.51	1.43	7.57E + 08	1.26

p-values were calculated using a Mann-Whitney test for unpaired comparison and a Wilcoxon signed rank test for paired comparison. The level of significance was set at *for p < 0.05, **for p < 0.01 and ***for p < 0.001.